minetest/doc/lua_api.md

Luanti Lua Modding API Reference

WARNING: if you're looking for the minetest namespace (e.g. minetest.something), it's now called core due to the renaming of Luanti (formerly Minetest). minetest will keep existing as an alias, so that old code won't break.

• More information at http://www.minetest.net/
• Developer Wiki: http://dev.minetest.net/
• (Unofficial) Minetest Modding Book by rubenwardy: https://rubenwardy.com/minetest_modding_book/
• Modding tools: https://github.com/minetest/modtools

Introduction

Content and functionality can be added to Luanti using Lua scripting in run-time loaded mods.

A mod is a self-contained bunch of scripts, textures and other related things, which is loaded by and interfaces with Luanti.

Mods are contained and ran solely on the server side. Definitions and media files are automatically transferred to the client.

If you see a deficiency in the API, feel free to attempt to add the functionality in the engine and API, and to document it here.

Programming in Lua

If you have any difficulty in understanding this, please read Programming in Lua.

Startup

Mods are loaded during server startup from the mod load paths by running the init.lua scripts in a shared environment.

Paths

Luanti keeps and looks for files mostly in two paths. path_share or path_user.

path_share contains possibly read-only content for the engine (incl. games and mods). path_user contains mods or games installed by the user but also the users worlds or settings.

With a local build (RUN_IN_PLACE=1) path_share and path_user both point to the build directory. For system-wide builds on Linux the share path is usually at /usr/share/minetest while the user path resides in .minetest in the home directory. Paths on other operating systems will differ.

Games

Games are looked up from:

• $path_share/games/<gameid>/
• $path_user/games/<gameid>/

Where <gameid> is unique to each game.

The game directory can contain the following files:

• game.conf, with the following keys:
  • title: Required, a human-readable title to address the game, e.g. title = Minetest Game.
  • name: (Deprecated) same as title.
  • description: Short description to be shown in the content tab. See Translating content meta.
  • first_mod: Use this to specify the mod that must be loaded before any other mod.
  • last_mod: Use this to specify the mod that must be loaded after all other mods
  • allowed_mapgens = <comma-separated mapgens> e.g. allowed_mapgens = v5,v6,flat Mapgens not in this list are removed from the list of mapgens for the game. If not specified, all mapgens are allowed.
  • disallowed_mapgens = <comma-separated mapgens> e.g. disallowed_mapgens = v5,v6,flat These mapgens are removed from the list of mapgens for the game. When both allowed_mapgens and disallowed_mapgens are specified, allowed_mapgens is applied before disallowed_mapgens.
  • disallowed_mapgen_settings= <comma-separated mapgen settings> e.g. disallowed_mapgen_settings = mgv5_spflags These mapgen settings are hidden for this game in the world creation dialog and game start menu. Add seed to hide the seed input field.
  • disabled_settings = <comma-separated settings> e.g. disabled_settings = enable_damage, creative_mode These settings are hidden for this game in the "Start game" tab and will be initialized as false when the game is started. Prepend a setting name with an exclamation mark to initialize it to true (this does not work for enable_server). Only these settings are supported: enable_damage, creative_mode, enable_server.
  • map_persistent: Specifies whether newly created worlds should use a persistent map backend. Defaults to true (= "sqlite3")
  • author: The author's ContentDB username.
  • release: Ignore this: Should only ever be set by ContentDB, as it is an internal ID used to track versions.
  • textdomain: Textdomain used to translate description. Defaults to game id. See Translating content meta.
• minetest.conf: Used to set default settings when running this game.
• settingtypes.txt: In the same format as the one in builtin. This settingtypes.txt will be parsed by the menu and the settings will be displayed in the "Games" category in the advanced settings tab.
• If the game contains a folder called textures the server will load it as a texturepack, overriding mod textures. Any server texturepack will override mod textures and the game texturepack.

Menu images

Games can provide custom main menu images. They are put inside a menu directory inside the game directory.

The images are named $identifier.png, where $identifier is one of overlay, background, footer, header. If you want to specify multiple images for one identifier, add additional images named like $identifier.$n.png, with an ascending number $n starting with 1, and a random image will be chosen from the provided ones.

Menu music

Games can provide custom main menu music. They are put inside a menu directory inside the game directory.

The music files are named theme.ogg. If you want to specify multiple music files for one game, add additional images named like theme.$n.ogg, with an ascending number $n starting with 1 (max 10), and a random music file will be chosen from the provided ones.

Mods

Mod load path

Paths are relative to the directories listed in the [Paths] section above.

• games/<gameid>/mods/
• mods/
• worlds/<worldname>/worldmods/

World-specific games

It is possible to include a game in a world; in this case, no mods or games are loaded or checked from anywhere else.

This is useful for e.g. adventure worlds and happens if the <worldname>/game/ directory exists.

Mods should then be placed in <worldname>/game/mods/.

Modpacks

Mods can be put in a subdirectory, if the parent directory, which otherwise should be a mod, contains a file named modpack.conf. The file is a key-value store of modpack details.

• name: The modpack name. Allows Luanti to determine the modpack name even if the folder is wrongly named.
• title: A human-readable title to address the modpack. See Translating content meta.
• description: Description of mod to be shown in the Mods tab of the main menu. See Translating content meta.
• author: The author's ContentDB username.
• release: Ignore this: Should only ever be set by ContentDB, as it is an internal ID used to track versions.
• textdomain: Textdomain used to translate title and description. Defaults to modpack name. See Translating content meta.

Note: to support 0.4.x, please also create an empty modpack.txt file.

Mod directory structure

mods
├── modname
│   ├── mod.conf
│   ├── screenshot.png
│   ├── settingtypes.txt
│   ├── init.lua
│   ├── models
│   ├── textures
│   │   ├── modname_stuff.png
│   │   ├── modname_stuff_normal.png
│   │   ├── modname_something_else.png
│   │   ├── subfolder_foo
│   │   │   ├── modname_more_stuff.png
│   │   │   └── another_subfolder
│   │   └── bar_subfolder
│   ├── sounds
│   ├── media
│   ├── locale
│   └── <custom data>
└── another

modname

The location of this directory can be fetched by using core.get_modpath(modname).

mod.conf

A Settings file that provides meta information about the mod.

• name: The mod name. Allows Luanti to determine the mod name even if the folder is wrongly named.
• title: A human-readable title to address the mod. See Translating content meta.
• description: Description of mod to be shown in the Mods tab of the main menu. See Translating content meta.
• depends: A comma separated list of dependencies. These are mods that must be loaded before this mod.
• optional_depends: A comma separated list of optional dependencies. Like a dependency, but no error if the mod doesn't exist.
• author: The author's ContentDB username.
• release: Ignore this: Should only ever be set by ContentDB, as it is an internal ID used to track versions.
• textdomain: Textdomain used to translate title and description. Defaults to modname. See Translating content meta.

screenshot.png

A screenshot shown in the mod manager within the main menu. It should have an aspect ratio of 3:2 and a minimum size of 300×200 pixels.

depends.txt

Deprecated: you should use mod.conf instead.

This file is used if there are no dependencies in mod.conf.

List of mods that have to be loaded before loading this mod.

A single line contains a single modname.

Optional dependencies can be defined by appending a question mark to a single modname. This means that if the specified mod is missing, it does not prevent this mod from being loaded.

description.txt

Deprecated: you should use mod.conf instead.

This file is used if there is no description in mod.conf.

A file containing a description to be shown in the Mods tab of the main menu.

settingtypes.txt

The format is documented in builtin/settingtypes.txt. It is parsed by the main menu settings dialogue to list mod-specific settings in the "Mods" category.

core.settings can be used to read custom or engine settings. See [Settings].

init.lua

The main Lua script. Running this script should register everything it wants to register. Subsequent execution depends on Luanti calling the registered callbacks.

textures, sounds, media, models, locale

Media files (textures, sounds, whatever) that will be transferred to the client and will be available for use by the mod and translation files for the clients (see [Translations]). Accepted characters for names are:

a-zA-Z0-9_.-

Accepted formats are:

images: .png, .jpg, .tga
sounds: .ogg vorbis
models: .x, .b3d, .obj, (since version 5.10:) .gltf, .glb

Other formats won't be sent to the client (e.g. you can store .blend files in a folder for convenience, without the risk that such files are transferred)

It is suggested to use the folders for the purpose they are thought for, eg. put textures into textures, translation files into locale, models for entities or meshnodes into models et cetera.

These folders and subfolders can contain subfolders. Subfolders with names starting with _ or . are ignored. If a subfolder contains a media file with the same name as a media file in one of its parents, the parent's file is used.

Although it is discouraged, a mod can overwrite a media file of any mod that it depends on by supplying a file with an equal name.

Only a subset of model file format features is supported:

Simple textured meshes (with multiple textures), optionally with normals. The .x, .b3d and .gltf formats additionally support (a single) animation.

glTF

The glTF model file format for now only serves as a more modern alternative to the other static model file formats; it unlocks no special rendering features.

Binary glTF (.glb) files are supported and recommended over .gltf files due to their space savings.

Bone weights should be normalized, e.g. using "normalize all" in Blender.

You can use the Khronos glTF validator to check whether a model is a valid glTF file.

Many glTF features are not supported yet, including:

• Animations
  • Only a single animation is supported, use frame ranges within this animation.
  • Only linear interpolation is supported.
• Cameras
• Materials
  • Only base color textures are supported
  • Backface culling is overridden
  • Double-sided materials don't work
• Alternative means of supplying data
  • Embedded images. You can use gltfutil.py from the modding tools to strip or extract embedded images.
  • References to files via URIs

Textures are supplied solely via the same means as for the other model file formats: The textures object property, the tiles node definition field and the list of textures used in the model[] formspec element.

The order in which textures are to be supplied is that in which they appear in the textures array in the glTF file.

Do not rely on glTF features not being supported; they may be supported in the future. The backwards compatibility guarantee does not extend to ignoring unsupported features.

For example, if your model used an emissive material, you should expect that a future version of Luanti may respect this, and thus cause your model to render differently there.

Naming conventions

Registered names should generally be in this format:

modname:<whatever>

<whatever> can have these characters:

a-zA-Z0-9_

This is to prevent conflicting names from corrupting maps and is enforced by the mod loader.

Registered names can be overridden by prefixing the name with :. This can be used for overriding the registrations of some other mod.

The : prefix can also be used for maintaining backwards compatibility.

Example

In the mod experimental, there is the ideal item/node/entity name tnt. So the name should be experimental:tnt.

Any mod can redefine experimental:tnt by using the name

:experimental:tnt

when registering it. For this to work correctly, that mod must have experimental as a dependency.

Aliases

Aliases of itemnames can be added by using core.register_alias(alias, original_name) or core.register_alias_force(alias, original_name).

This adds an alias alias for the item called original_name. From now on, you can use alias to refer to the item original_name.

The only difference between core.register_alias and core.register_alias_force is that if an item named alias already exists, core.register_alias will do nothing while core.register_alias_force will unregister it.

This can be used for maintaining backwards compatibility.

This can also set quick access names for things, e.g. if you have an item called epiclylongmodname:stuff, you could do

core.register_alias("stuff", "epiclylongmodname:stuff")

and be able to use /giveme stuff.

Mapgen aliases

In a game, a certain number of these must be set to tell core mapgens which of the game's nodes are to be used for core mapgen generation. For example:

core.register_alias("mapgen_stone", "default:stone")

Aliases for non-V6 mapgens

Essential aliases

• mapgen_stone
• mapgen_water_source
• mapgen_river_water_source

mapgen_river_water_source is required for mapgens with sloping rivers where it is necessary to have a river liquid node with a short liquid_range and liquid_renewable = false to avoid flooding.

Optional aliases

• mapgen_lava_source

Fallback lava node used if cave liquids are not defined in biome definitions. Deprecated, define cave liquids in biome definitions instead.

• mapgen_cobble

Fallback node used if dungeon nodes are not defined in biome definitions. Deprecated, define dungeon nodes in biome definitions instead.

Aliases for Mapgen V6

Essential

• mapgen_stone
• mapgen_water_source
• mapgen_lava_source
• mapgen_dirt
• mapgen_dirt_with_grass

• mapgen_sand

• mapgen_tree

• mapgen_leaves

• mapgen_apple

• mapgen_cobble

Optional

• mapgen_gravel (falls back to stone)
• mapgen_desert_stone (falls back to stone)
• mapgen_desert_sand (falls back to sand)
• mapgen_dirt_with_snow (falls back to dirt_with_grass)
• mapgen_snowblock (falls back to dirt_with_grass)
• mapgen_snow (not placed if missing)

• mapgen_ice (falls back to water_source)

• mapgen_jungletree (falls back to tree)

• mapgen_jungleleaves (falls back to leaves)

• mapgen_junglegrass (not placed if missing)

• mapgen_pine_tree (falls back to tree)

• mapgen_pine_needles (falls back to leaves)

• mapgen_stair_cobble (falls back to cobble)

• mapgen_mossycobble (falls back to cobble)

• mapgen_stair_desert_stone (falls back to desert_stone)

Setting the node used in Mapgen Singlenode

By default the world is filled with air nodes. To set a different node use e.g.:

core.register_alias("mapgen_singlenode", "default:stone")

Textures

Mods should generally prefix their textures with modname_, e.g. given the mod name foomod, a texture could be called:

foomod_foothing.png

Textures are referred to by their complete name, or alternatively by stripping out the file extension:

• e.g. foomod_foothing.png
• e.g. foomod_foothing

Supported texture formats are PNG (.png), JPEG (.jpg) and Targa (.tga).

Texture modifiers

There are various texture modifiers that can be used to let the client generate textures on-the-fly. The modifiers are applied directly in sRGB colorspace, i.e. without gamma-correction.

Notes

• TEXMOD_UPSCALE: The texture with the lower resolution will be automatically upscaled to the higher resolution texture.

Texture overlaying

Textures can be overlaid by putting a ^ between them.

Warning: If the lower and upper pixels are both semi-transparent, this operation does not do alpha blending, and it is not associative. Otherwise it does alpha blending in srgb color space.

Example:

default_dirt.png^default_grass_side.png

default_grass_side.png is overlaid over default_dirt.png.

See notes: TEXMOD_UPSCALE

Texture grouping

Textures can be grouped together by enclosing them in ( and ).

Example: cobble.png^(thing1.png^thing2.png)

A texture for thing1.png^thing2.png is created and the resulting texture is overlaid on top of cobble.png.

Escaping

Modifiers that accept texture names (e.g. [combine) accept escaping to allow passing complex texture names as arguments. Escaping is done with backslash and is required for ^, : and \.

Example: cobble.png^[lowpart:50:color.png\^[mask\:trans.png Or as a Lua string: "cobble.png^[lowpart:50:color.png\\^[mask\\:trans.png"

The lower 50 percent of color.png^[mask:trans.png are overlaid on top of cobble.png.

Advanced texture modifiers

Crack

• [crack:<n>:<p>
• [cracko:<n>:<p>
• [crack:<t>:<n>:<p>
• [cracko:<t>:<n>:<p>

Parameters:

• <t>: tile count (in each direction)
• <n>: animation frame count
• <p>: current animation frame

Draw a step of the crack animation on the texture. crack draws it normally, while cracko lays it over, keeping transparent pixels intact.

Example:

default_cobble.png^[crack:10:1

[combine:<w>x<h>:<x1>,<y1>=<file1>:<x2>,<y2>=<file2>:...

• <w>: width
• <h>: height
• <x>: x position, negative numbers allowed
• <y>: y position, negative numbers allowed
• <file>: texture to combine

Creates a texture of size <w> times <h> and blits the listed files to their specified coordinates.

Example:

[combine:16x32:0,0=default_cobble.png:0,16=default_wood.png

[resize:<w>x<h>

Resizes the texture to the given dimensions.

Example:

default_sandstone.png^[resize:16x16

[opacity:<r>

Makes the base image transparent according to the given ratio.

r must be between 0 (transparent) and 255 (opaque).

Example:

default_sandstone.png^[opacity:127

[invert:<mode>

Inverts the given channels of the base image. Mode may contain the characters "r", "g", "b", "a". Only the channels that are mentioned in the mode string will be inverted.

Example:

default_apple.png^[invert:rgb

[brighten

Brightens the texture.

Example:

tnt_tnt_side.png^[brighten

[noalpha

Makes the texture completely opaque.

Example:

default_leaves.png^[noalpha

[makealpha:<r>,<g>,<b>

Convert one color to transparency.

Example:

default_cobble.png^[makealpha:128,128,128

[transform<t>

• <t>: transformation(s) to apply

Rotates and/or flips the image.

<t> can be a number (between 0 and 7) or a transform name. Rotations are counter-clockwise.

0  I      identity
1  R90    rotate by 90 degrees
2  R180   rotate by 180 degrees
3  R270   rotate by 270 degrees
4  FX     flip X
5  FXR90  flip X then rotate by 90 degrees
6  FY     flip Y
7  FYR90  flip Y then rotate by 90 degrees

Example:

default_stone.png^[transformFXR90

[inventorycube{<top>{<left>{<right>

Escaping does not apply here and ^ is replaced by & in texture names instead.

Create an inventory cube texture using the side textures.

Example:

[inventorycube{grass.png{dirt.png&grass_side.png{dirt.png&grass_side.png

Creates an inventorycube with grass.png, dirt.png^grass_side.png and dirt.png^grass_side.png textures

[fill:<w>x<h>:<x>,<y>:<color>

• <w>: width
• <h>: height
• <x>: x position
• <y>: y position
• <color>: a ColorString.

Creates a texture of the given size and color, optionally with an <x>,<y> position. An alpha value may be specified in the Colorstring.

The optional <x>,<y> position is only used if the [fill is being overlaid onto another texture with '^'.

When [fill is overlaid onto another texture it will not upscale or change the resolution of the texture, the base texture will determine the output resolution.

Examples:

[fill:16x16:#20F02080
texture.png^[fill:8x8:4,4:red

[lowpart:<percent>:<file>

Blit the lower <percent>% part of <file> on the texture.

Example:

base.png^[lowpart:25:overlay.png

[verticalframe:<t>:<n>

• <t>: animation frame count
• <n>: current animation frame

Crops the texture to a frame of a vertical animation.

Example:

default_torch_animated.png^[verticalframe:16:8

[mask:<file>

Apply a mask to the base image.

The mask is applied using binary AND.

See notes: TEXMOD_UPSCALE

[sheet:<w>x<h>:<x>,<y>

Retrieves a tile at position x, y (in tiles, 0-indexed) from the base image, which it assumes to be a tilesheet with dimensions w, h (in tiles).

[colorize:<color>:<ratio>

Colorize the textures with the given color. <color> is specified as a ColorString. <ratio> is an int ranging from 0 to 255 or the word "alpha". If it is an int, then it specifies how far to interpolate between the colors where 0 is only the texture color and 255 is only <color>. If omitted, the alpha of <color> will be used as the ratio. If it is the word "alpha", then each texture pixel will contain the RGB of <color> and the alpha of <color> multiplied by the alpha of the texture pixel.

[colorizehsl:<hue>:<saturation>:<lightness>

Colorize the texture to the given hue. The texture will be converted into a greyscale image as seen through a colored glass, like "Colorize" in GIMP. Saturation and lightness can optionally be adjusted.

<hue> should be from -180 to +180. The hue at 0° on an HSL color wheel is red, 60° is yellow, 120° is green, and 180° is cyan, while -60° is magenta and -120° is blue.

<saturation> and <lightness> are optional adjustments.

<lightness> is from -100 to +100, with a default of 0

<saturation> is from 0 to 100, with a default of 50

[multiply:<color>

Multiplies texture colors with the given color. <color> is specified as a ColorString. Result is more like what you'd expect if you put a color on top of another color, meaning white surfaces get a lot of your new color while black parts don't change very much.

A Multiply blend can be applied between two textures by using the overlay modifier with a brightness adjustment:

textureA.png^[contrast:0:-64^[overlay:textureB.png

[screen:<color>

Apply a Screen blend with the given color. A Screen blend is the inverse of a Multiply blend, lightening images instead of darkening them.

<color> is specified as a ColorString.

A Screen blend can be applied between two textures by using the overlay modifier with a brightness adjustment:

textureA.png^[contrast:0:64^[overlay:textureB.png

[hsl:<hue>:<saturation>:<lightness>

Adjust the hue, saturation, and lightness of the texture. Like "Hue-Saturation" in GIMP, but with 0 as the mid-point.

<hue> should be from -180 to +180

<saturation> and <lightness> are optional, and both percentages.

<lightness> is from -100 to +100.

<saturation> goes down to -100 (fully desaturated) but may go above 100, allowing for even muted colors to become highly saturated.

[contrast:<contrast>:<brightness>

Adjust the brightness and contrast of the texture. Conceptually like GIMP's "Brightness-Contrast" feature but allows brightness to be wound all the way up to white or down to black.

<contrast> is a value from -127 to +127.

<brightness> is an optional value, from -127 to +127.

If only a boost in contrast is required, an alternative technique is to hardlight blend the texture with itself, this increases contrast in the same way as an S-shaped color-curve, which avoids dark colors clipping to black and light colors clipping to white:

texture.png^[hardlight:texture.png

[overlay:<file>

Applies an Overlay blend with the two textures, like the Overlay layer mode in GIMP. Overlay is the same as Hard light but with the role of the two textures swapped, see the [hardlight modifier description for more detail about these blend modes.

See notes: TEXMOD_UPSCALE

[hardlight:<file>

Applies a Hard light blend with the two textures, like the Hard light layer mode in GIMP.

Hard light combines Multiply and Screen blend modes. Light parts of the <file> texture will lighten (screen) the base texture, and dark parts of the <file> texture will darken (multiply) the base texture. This can be useful for applying embossing or chiselled effects to textures. A Hard light with the same texture acts like applying an S-shaped color-curve, and can be used to increase contrast without clipping.

Hard light is the same as Overlay but with the roles of the two textures swapped, i.e. A.png^[hardlight:B.png is the same as B.png^[overlay:A.png

See notes: TEXMOD_UPSCALE

[png:<base64>

Embed a base64 encoded PNG image in the texture string. You can produce a valid string for this by calling core.encode_base64(core.encode_png(tex)), where tex is pixel data. Refer to the documentation of these functions for details. You can use this to send disposable images such as captchas to individual clients, or render things that would be too expensive to compose with [combine:.

IMPORTANT: Avoid sending large images this way. This is not a replacement for asset files, do not use it to do anything that you could instead achieve by just using a file. In particular consider core.dynamic_add_media and test whether using other texture modifiers could result in a shorter string than embedding a whole image, this may vary by use case.

See notes: TEXMOD_UPSCALE

Hardware coloring

The goal of hardware coloring is to simplify the creation of colorful nodes. If your textures use the same pattern, and they only differ in their color (like colored wool blocks), you can use hardware coloring instead of creating and managing many texture files. All of these methods use color multiplication (so a white-black texture with red coloring will result in red-black color).

Static coloring

This method is useful if you wish to create nodes/items with the same texture, in different colors, each in a new node/item definition.

Global color

When you register an item or node, set its color field (which accepts a ColorSpec) to the desired color.

An ItemStack's static color can be overwritten by the color metadata field. If you set that field to a ColorString, that color will be used.

Tile color

Each tile may have an individual static color, which overwrites every other coloring method. To disable the coloring of a face, set its color to white (because multiplying with white does nothing). You can set the color property of the tiles in the node's definition if the tile is in table format.

Palettes

For nodes and items which can have many colors, a palette is more suitable. A palette is a texture, which can contain up to 256 pixels. Each pixel is one possible color for the node/item. You can register one node/item, which can have up to 256 colors.

Palette indexing

When using palettes, you always provide a pixel index for the given node or ItemStack. The palette is read from left to right and from top to bottom. If the palette has less than 256 pixels, then it is stretched to contain exactly 256 pixels (after arranging the pixels to one line). The indexing starts from 0.

Examples:

• 16x16 palette, index = 0: the top left corner
• 16x16 palette, index = 4: the fifth pixel in the first row
• 16x16 palette, index = 16: the pixel below the top left corner
• 16x16 palette, index = 255: the bottom right corner
• 2 (width) x 4 (height) palette, index = 31: the top left corner. The palette has 8 pixels, so each pixel is stretched to 32 pixels, to ensure the total 256 pixels.
• 2x4 palette, index = 32: the top right corner
• 2x4 palette, index = 63: the top right corner
• 2x4 palette, index = 64: the pixel below the top left corner

Using palettes with items

When registering an item, set the item definition's palette field to a texture. You can also use texture modifiers.

The ItemStack's color depends on the palette_index field of the stack's metadata. palette_index is an integer, which specifies the index of the pixel to use.

Linking palettes with nodes

When registering a node, set the item definition's palette field to a texture. You can also use texture modifiers. The node's color depends on its param2, so you also must set an appropriate paramtype2:

• paramtype2 = "color" for nodes which use their full param2 for palette indexing. These nodes can have 256 different colors. The palette should contain 256 pixels.
• paramtype2 = "colorwallmounted" for nodes which use the first five bits (most significant) of param2 for palette indexing. The remaining three bits are describing rotation, as in wallmounted paramtype2. Division by 8 yields the palette index (without stretching the palette). These nodes can have 32 different colors, and the palette should contain 32 pixels. Examples:
  • param2 = 17 is 2 * 8 + 1, so the rotation is 1 and the third (= 2 + 1) pixel will be picked from the palette.
  • param2 = 35 is 4 * 8 + 3, so the rotation is 3 and the fifth (= 4 + 1) pixel will be picked from the palette.
• paramtype2 = "colorfacedir" for nodes which use the first three bits of param2 for palette indexing. The remaining five bits are describing rotation, as in facedir paramtype2. Division by 32 yields the palette index (without stretching the palette). These nodes can have 8 different colors, and the palette should contain 8 pixels. Examples:
  • param2 = 17 is 0 * 32 + 17, so the rotation is 17 and the first (= 0 + 1) pixel will be picked from the palette.
  • param2 = 35 is 1 * 32 + 3, so the rotation is 3 and the second (= 1 + 1) pixel will be picked from the palette.
• paramtype2 = "color4dir" for nodes which use the first six bits of param2 for palette indexing. The remaining two bits are describing rotation, as in 4dir paramtype2. Division by 4 yields the palette index (without stretching the palette). These nodes can have 64 different colors, and the palette should contain 64 pixels. Examples:
  • param2 = 17 is 4 * 4 + 1, so the rotation is 1 and the fifth (= 4 + 1) pixel will be picked from the palette.
  • param2 = 35 is 8 * 4 + 3, so the rotation is 3 and the ninth (= 8 + 1) pixel will be picked from the palette.

To colorize a node on the map, set its param2 value (according to the node's paramtype2).

Conversion between nodes in the inventory and on the map

Static coloring is the same for both cases, there is no need for conversion.

If the ItemStack's metadata contains the color field, it will be lost on placement, because nodes on the map can only use palettes.

If the ItemStack's metadata contains the palette_index field, it is automatically transferred between node and item forms by the engine, when a player digs or places a colored node. You can disable this feature by setting the drop field of the node to itself (without metadata). To transfer the color to a special drop, you need a drop table.

Example:

core.register_node("mod:stone", {
    description = "Stone",
    tiles = {"default_stone.png"},
    paramtype2 = "color",
    palette = "palette.png",
    drop = {
        items = {
            -- assume that mod:cobblestone also has the same palette
            {items = {"mod:cobblestone"}, inherit_color = true },
        }
    }
})

Colored items in craft recipes

Craft recipes only support item strings, but fortunately item strings can also contain metadata. Example craft recipe registration:

core.register_craft({
    output = core.itemstring_with_palette("wool:block", 3),
    type = "shapeless",
    recipe = {
        "wool:block",
        "dye:red",
    },
})

To set the color field, you can use core.itemstring_with_color.

Metadata field filtering in the recipe field are not supported yet, so the craft output is independent of the color of the ingredients.

Soft texture overlay

Sometimes hardware coloring is not enough, because it affects the whole tile. Soft texture overlays were added to Luanti to allow the dynamic coloring of only specific parts of the node's texture. For example a grass block may have colored grass, while keeping the dirt brown.

These overlays are 'soft', because unlike texture modifiers, the layers are not merged in the memory, but they are simply drawn on top of each other. This allows different hardware coloring, but also means that tiles with overlays are drawn slower. Using too much overlays might cause FPS loss.

For inventory and wield images you can specify overlays which hardware coloring does not modify. You have to set inventory_overlay and wield_overlay fields to an image name.

To define a node overlay, simply set the overlay_tiles field of the node definition. These tiles are defined in the same way as plain tiles: they can have a texture name, color etc. To skip one face, set that overlay tile to an empty string.

Example (colored grass block):

core.register_node("default:dirt_with_grass", {
    description = "Dirt with Grass",
    -- Regular tiles, as usual
    -- The dirt tile disables palette coloring
    tiles = {{name = "default_grass.png"},
        {name = "default_dirt.png", color = "white"}},
    -- Overlay tiles: define them in the same style
    -- The top and bottom tile does not have overlay
    overlay_tiles = {"", "",
        {name = "default_grass_side.png"}},
    -- Global color, used in inventory
    color = "green",
    -- Palette in the world
    paramtype2 = "color",
    palette = "default_foilage.png",
})

Sounds

Only Ogg Vorbis files are supported.

For positional playing of sounds, only single-channel (mono) files are supported. Otherwise OpenAL will play them non-positionally.

Mods should generally prefix their sound files with modname_, e.g. given the mod name "foomod", a sound could be called:

foomod_foosound.ogg

Sound group

A sound group is the set of all sound files, whose filenames are of the following format: <sound-group name>[.<single digit>].ogg When a sound-group is played, one the files in the group is chosen at random. Sound files can only be referred to by their sound-group name.

Example: When playing the sound foomod_foosound, the sound is chosen randomly from the available ones of the following files:

• foomod_foosound.ogg
• foomod_foosound.0.ogg
• foomod_foosound.1.ogg
• (...)
• foomod_foosound.9.ogg

SimpleSoundSpec

Specifies a sound name, gain (=volume), pitch and fade. This is either a string or a table.

In string form, you just specify the sound name or the empty string for no sound.

Table form has the following fields:

• name: Sound-group name. If == "", no sound is played.
• gain: Volume (1.0 = 100%), must be non-negative. At the end, OpenAL clamps sound gain to a maximum of 1.0. By setting gain for a positional sound higher than 1.0, one can increase the radius inside which maximal gain is reached. Furthermore, gain of positional sounds doesn't increase inside a 1 node radius. The gain given here describes the gain at a distance of 3 nodes.
• pitch: Applies a pitch-shift to the sound. Each factor of 2.0 results in a pitch-shift of +12 semitones. Must be positive.
• fade: If > 0.0, the sound is faded in, with this value in gain per second, until gain is reached.

gain, pitch and fade are optional and default to 1.0, 1.0 and 0.0.

Examples:

• "": No sound
• {}: No sound
• "default_place_node": Play e.g. default_place_node.ogg
• {name = "default_place_node"}: Same as above
• {name = "default_place_node", gain = 0.5}: 50% volume
• {name = "default_place_node", gain = 0.9, pitch = 1.1}: 90% volume, 110% pitch

Sound parameter table

Table used to specify how a sound is played:

{
    gain = 1.0,
    -- Scales the gain specified in `SimpleSoundSpec`.

    pitch = 1.0,
    -- Overwrites the pitch specified in `SimpleSoundSpec`.

    fade = 0.0,
    -- Overwrites the fade specified in `SimpleSoundSpec`.

    start_time = 0.0,
    -- Start with a time-offset into the sound.
    -- The behavior is as if the sound was already playing for this many seconds.
    -- Negative values are relative to the sound's length, so the sound reaches
    -- its end in `-start_time` seconds.
    -- It is unspecified what happens if `loop` is false and `start_time` is
    -- smaller than minus the sound's length.
    -- Available since feature `sound_params_start_time`.

    loop = false,
    -- If true, sound is played in a loop.

    pos = {x = 1, y = 2, z = 3},
    -- Play sound at a position.
    -- Can't be used together with `object`.

    object = <an ObjectRef>,
    -- Attach the sound to an object.
    -- Can't be used together with `pos`.

    to_player = name,
    -- Only play for this player.
    -- Can't be used together with `exclude_player`.

    exclude_player = name,
    -- Don't play sound for this player.
    -- Can't be used together with `to_player`.

    max_hear_distance = 32,
    -- Only play for players that are at most this far away when the sound
    -- starts playing.
    -- Needs `pos` or `object` to be set.
    -- `32` is the default.
}

Examples:

-- Play locationless on all clients
{
    gain = 1.0,   -- default
    fade = 0.0,   -- default
    pitch = 1.0,  -- default
}
-- Play locationless to one player
{
    to_player = name,
    gain = 1.0,   -- default
    fade = 0.0,   -- default
    pitch = 1.0,  -- default
}
-- Play locationless to one player, looped
{
    to_player = name,
    gain = 1.0,  -- default
    loop = true,
}
-- Play at a location, start the sound at offset 5 seconds
{
    pos = {x = 1, y = 2, z = 3},
    gain = 1.0,  -- default
    max_hear_distance = 32,  -- default
    start_time = 5.0,
}
-- Play connected to an object, looped
{
    object = <an ObjectRef>,
    gain = 1.0,  -- default
    max_hear_distance = 32,  -- default
    loop = true,
}
-- Play at a location, heard by anyone *but* the given player
{
    pos = {x = 32, y = 0, z = 100},
    max_hear_distance = 40,
    exclude_player = name,
}

Special sound-groups

These sound-groups are played back by the engine if provided.

• player_damage: Played when the local player takes damage (gain = 0.5)
• player_falling_damage: Played when the local player takes damage by falling (gain = 0.5)
• player_jump: Played when the local player jumps
• default_dig_<groupname>: Default node digging sound (gain = 0.5) (see node sound definition for details)

Registered definitions

Anything added using certain [Registration functions] gets added to one or more of the global [Registered definition tables].

Note that in some cases you will stumble upon things that are not contained in these tables (e.g. when a mod has been removed). Always check for existence before trying to access the fields.

Example:

All nodes registered with core.register_node get added to the table core.registered_nodes.

If you want to check the drawtype of a node, you could do it like this:

local def = core.registered_nodes[nodename]
local drawtype = def and def.drawtype

Nodes

Nodes are the bulk data of the world: cubes and other things that take the space of a cube. Huge amounts of them are handled efficiently, but they are quite static.

The definition of a node is stored and can be accessed by using

core.registered_nodes[node.name]

See [Registered definitions].

Nodes are passed by value between Lua and the engine. They are represented by a table:

{name="name", param1=num, param2=num}

param1 and param2 are 8-bit integers ranging from 0 to 255. The engine uses them for certain automated functions. If you don't use these functions, you can use them to store arbitrary values.

Node paramtypes

The functions of param1 and param2 are determined by certain fields in the node definition.

The function of param1 is determined by paramtype in node definition. param1 is reserved for the engine when paramtype != "none".

• paramtype = "light"
  • The value stores light with and without sun in its lower and upper 4 bits respectively.
  • Required by a light source node to enable spreading its light.
  • Required by the following drawtypes as they determine their visual brightness from their internal light value:
    • torchlike
    • signlike
    • firelike
    • fencelike
    • raillike
    • nodebox
    • mesh
    • plantlike
    • plantlike_rooted
• paramtype = "none"
  • param1 will not be used by the engine and can be used to store an arbitrary value

The function of param2 is determined by paramtype2 in node definition. param2 is reserved for the engine when paramtype2 != "none".

• paramtype2 = "flowingliquid"
  • Used by drawtype = "flowingliquid" and liquidtype = "flowing"
  • The liquid level and a flag of the liquid are stored in param2
  • Bits 0-2: Liquid level (0-7). The higher, the more liquid is in this node; see core.get_node_level, core.set_node_level and core.add_node_level to access/manipulate the content of this field
  • Bit 3: If set, liquid is flowing downwards (no graphical effect)
• paramtype2 = "wallmounted"
  • Supported drawtypes: "torchlike", "signlike", "plantlike", "plantlike_rooted", "normal", "nodebox", "mesh"
  • The rotation of the node is stored in param2
  • Node is 'mounted'/facing towards one of 6 directions
  • You can make this value by using core.dir_to_wallmounted()
  • Values range 0 - 7
  • The value denotes at which direction the node is "mounted": 0 = y+, 1 = y-, 2 = x+, 3 = x-, 4 = z+, 5 = z- 6 = y+, but rotated by 90° 7 = y-, but rotated by -90°
  • By default, on placement the param2 is automatically set to the appropriate rotation (0 to 5), depending on which side was pointed at. With the node field wallmounted_rotate_vertical = true, the param2 values 6 and 7 might additionally be set
• paramtype2 = "facedir"
  • Supported drawtypes: "normal", "nodebox", "mesh"
  • The rotation of the node is stored in param2.
  • Node is rotated around face and axis; 24 rotations in total.
  • Can be made by using core.dir_to_facedir().
  • Chests and furnaces can be rotated that way, and also 'flipped'
  • Values range 0 - 23
  • facedir / 4 = axis direction: 0 = y+, 1 = z+, 2 = z-, 3 = x+, 4 = x-, 5 = y-
  • The node is rotated 90 degrees around the X or Z axis so that its top face points in the desired direction. For the y- direction, it's rotated 180 degrees around the Z axis.
  • facedir modulo 4 = left-handed rotation around the specified axis, in 90° steps.
  • By default, on placement the param2 is automatically set to the horizontal direction the player was looking at (values 0-3)
  • Special case: If the node is a connected nodebox, the nodebox will NOT rotate, only the textures will.
• paramtype2 = "4dir"
  • Supported drawtypes: "normal", "nodebox", "mesh"
  • The rotation of the node is stored in param2.
  • Allows node to be rotated horizontally, 4 rotations in total
  • Can be made by using core.dir_to_fourdir().
  • Chests and furnaces can be rotated that way, but not flipped
  • Values range 0 - 3
  • 4dir modulo 4 = rotation
  • Otherwise, behavior is identical to facedir
• paramtype2 = "leveled"
  • Only valid for "nodebox" with 'type = "leveled"', and "plantlike_rooted".
    • Leveled nodebox:
      • The level of the top face of the nodebox is stored in param2.
      • The other faces are defined by 'fixed = {}' like 'type = "fixed"' nodeboxes.
      • The nodebox height is (param2 / 64) nodes.
      • The maximum accepted value of param2 is 127.
    • Rooted plantlike:
      • The height of the 'plantlike' section is stored in param2.
      • The height is (param2 / 16) nodes.
• paramtype2 = "degrotate"
  • Valid for plantlike and mesh drawtypes. The rotation of the node is stored in param2.
  • Values range 0–239. The value stored in param2 is multiplied by 1.5 to get the actual rotation in degrees of the node.
• paramtype2 = "meshoptions"
  • Only valid for "plantlike" drawtype. param2 encodes the shape and optional modifiers of the "plant". param2 is a bitfield.
  • Bits 0 to 2 select the shape. Use only one of the values below:
    • 0 = an "x" shaped plant (ordinary plant)
    • 1 = a "+" shaped plant (just rotated 45 degrees)
    • 2 = a "*" shaped plant with 3 faces instead of 2
    • 3 = a "#" shaped plant with 4 faces instead of 2
    • 4 = a "#" shaped plant with 4 faces that lean outwards
    • 5-7 are unused and reserved for future meshes.
  • Bits 3 to 7 are used to enable any number of optional modifiers. Just add the corresponding value(s) below to param2:
    • 8 - Makes the plant slightly vary placement horizontally
    • 16 - Makes the plant mesh 1.4x larger
    • 32 - Moves each face randomly a small bit down (1/8 max)
    • values 64 and 128 (bits 6-7) are reserved for future use.
  • Example: param2 = 0 selects a normal "x" shaped plant
  • Example: param2 = 17 selects a "+" shaped plant, 1.4x larger (1+16)
• paramtype2 = "color"
  • param2 tells which color is picked from the palette. The palette should have 256 pixels.
• paramtype2 = "colorfacedir"
  • Same as facedir, but with colors.
  • The three most significant bits of param2 tells which color is picked from the palette. The palette should have 8 pixels.
  • The five least significant bits contain the facedir value.
• paramtype2 = "color4dir"
  • Same as 4dir, but with colors.
  • The six most significant bits of param2 tells which color is picked from the palette. The palette should have 64 pixels.
  • The two least significant bits contain the 4dir rotation.
• paramtype2 = "colorwallmounted"
  • Same as wallmounted, but with colors.
  • The five most significant bits of param2 tells which color is picked from the palette. The palette should have 32 pixels.
  • The three least significant bits contain the wallmounted value.
• paramtype2 = "glasslikeliquidlevel"
  • Only valid for "glasslike_framed" or "glasslike_framed_optional" drawtypes. "glasslike_framed_optional" nodes are only affected if the "Connected Glass" setting is enabled.
  • Bits 0-5 define 64 levels of internal liquid, 0 being empty and 63 being full.
  • Bits 6 and 7 modify the appearance of the frame and node faces. One or both of these values may be added to param2:
    • 64 - Makes the node not connect with neighbors above or below it.
    • 128 - Makes the node not connect with neighbors to its sides.
  • Liquid texture is defined using special_tiles = {"modname_tilename.png"}
• paramtype2 = "colordegrotate"
  • Same as degrotate, but with colors.
  • The three most significant bits of param2 tells which color is picked from the palette. The palette should have 8 pixels.
  • The five least significant bits store rotation in range 0–23 (i.e. in 15° steps)
• paramtype2 = "none"
  • param2 will not be used by the engine and can be used to store an arbitrary value

Nodes can also contain extra data. See [Node Metadata].

Node drawtypes

There are a bunch of different looking node types.

Look for examples in games/devtest or games/minetest_game.

• normal
  • A node-sized cube.
• airlike
  • Invisible, uses no texture.
• liquid
  • The cubic source node for a liquid.
  • Faces bordering to the same node are never rendered.
  • Connects to node specified in liquid_alternative_flowing if specified.
  • Use backface_culling = false for the tiles you want to make visible when inside the node.
• flowingliquid
  • The flowing version of a liquid, appears with various heights and slopes.
  • Faces bordering to the same node are never rendered.
  • Connects to node specified in liquid_alternative_source.
  • You must set liquid_alternative_flowing to the node's own name.
  • Node textures are defined with special_tiles where the first tile is for the top and bottom faces and the second tile is for the side faces.
  • tiles is used for the item/inventory/wield image rendering.
  • Use backface_culling = false for the special tiles you want to make visible when inside the node
• glasslike
  • Often used for partially-transparent nodes.
  • Only external sides of textures are visible.
• glasslike_framed
  • All face-connected nodes are drawn as one volume within a surrounding frame.
  • The frame appearance is generated from the edges of the first texture specified in tiles. The width of the edges used are 1/16th of texture size: 1 pixel for 16x16, 2 pixels for 32x32 etc.
  • The glass 'shine' (or other desired detail) on each node face is supplied by the second texture specified in tiles.
• glasslike_framed_optional
  • This switches between the above 2 drawtypes according to the menu setting 'Connected Glass'.
• allfaces
  • Often used for partially-transparent nodes.
  • External sides of textures, and unlike other drawtypes, the external sides of other blocks, are visible from the inside.
• allfaces_optional
  • Often used for leaves nodes.
  • This switches between normal, glasslike and allfaces according to the menu setting: Opaque Leaves / Simple Leaves / Fancy Leaves.
  • With 'Simple Leaves' selected, the texture specified in special_tiles is used instead, if present. This allows a visually thicker texture to be used to compensate for how glasslike reduces visual thickness.
• torchlike
  • A single vertical texture.
  • If paramtype2="[color]wallmounted":
    • If placed on top of a node, uses the first texture specified in tiles.
    • If placed against the underside of a node, uses the second texture specified in tiles.
    • If placed on the side of a node, uses the third texture specified in tiles and is perpendicular to that node.
  • If paramtype2="none":
    • Will be rendered as if placed on top of a node (see above) and only the first texture is used.
• signlike
  • A single texture parallel to, and mounted against, the top, underside or side of a node.
  • If paramtype2="[color]wallmounted", it rotates according to param2
  • If paramtype2="none", it will always be on the floor.
• plantlike
  • Two vertical and diagonal textures at right-angles to each other.
  • See paramtype2 = "meshoptions" above for other options.
• firelike
  • When above a flat surface, appears as 6 textures, the central 2 as plantlike plus 4 more surrounding those.
  • If not above a surface the central 2 do not appear, but the texture appears against the faces of surrounding nodes if they are present.
• fencelike
  • A 3D model suitable for a wooden fence.
  • One placed node appears as a single vertical post.
  • Adjacently-placed nodes cause horizontal bars to appear between them.
• raillike
  • Often used for tracks for mining carts.
  • Requires 4 textures to be specified in tiles, in order: Straight, curved, t-junction, crossing.
  • Each placed node automatically switches to a suitable rotated texture determined by the adjacent raillike nodes, in order to create a continuous track network.
  • Becomes a sloping node if placed against stepped nodes.
• nodebox
  • Often used for stairs and slabs.
  • Allows defining nodes consisting of an arbitrary number of boxes.
  • See [Node boxes] below for more information.
• mesh
  • Uses models for nodes.
  • Tiles should hold model materials textures.
  • Only static meshes are implemented.
  • For supported model formats see Irrlicht engine documentation.
• plantlike_rooted
  • Enables underwater plantlike without air bubbles around the nodes.
  • Consists of a base cube at the coordinates of the node plus a plantlike extension above
  • If paramtype2="leveled", theplantlikeextension has a height ofparam2 / 16` nodes, otherwise it's the height of 1 node
  • If paramtype2="wallmounted", the plantlike extension will be at one of the corresponding 6 sides of the base cube. Also, the base cube rotates like a normal cube would
  • The plantlike extension visually passes through any nodes above the base cube without affecting them.
  • The base cube texture tiles are defined as normal, the plantlike extension uses the defined special tile, for example: special_tiles = {{name = "default_papyrus.png"}},

*_optional drawtypes need less rendering time if deactivated (always client-side).

Node boxes

Node selection boxes are defined using "node boxes".

A nodebox is defined as any of:

{
    -- A normal cube; the default in most things
    type = "regular"
}
{
    -- A fixed box (or boxes) (facedir param2 is used, if applicable)
    type = "fixed",
    fixed = box OR {box1, box2, ...}
}
{
    -- A variable height box (or boxes) with the top face position defined
    -- by the node parameter 'leveled = ', or if 'paramtype2 == "leveled"'
    -- by param2.
    -- Other faces are defined by 'fixed = {}' as with 'type = "fixed"'.
    type = "leveled",
    fixed = box OR {box1, box2, ...}
}
{
    -- A box like the selection box for torches
    -- (wallmounted param2 is used, if applicable)
    type = "wallmounted",
    wall_top = box,
    wall_bottom = box,
    wall_side = box
}
{
    -- A node that has optional boxes depending on neighboring nodes'
    -- presence and type. See also `connects_to`.
    type = "connected",
    fixed = box OR {box1, box2, ...}
    connect_top = box OR {box1, box2, ...}
    connect_bottom = box OR {box1, box2, ...}
    connect_front = box OR {box1, box2, ...}
    connect_left = box OR {box1, box2, ...}
    connect_back = box OR {box1, box2, ...}
    connect_right = box OR {box1, box2, ...}
    -- The following `disconnected_*` boxes are the opposites of the
    -- `connect_*` ones above, i.e. when a node has no suitable neighbor
    -- on the respective side, the corresponding disconnected box is drawn.
    disconnected_top = box OR {box1, box2, ...}
    disconnected_bottom = box OR {box1, box2, ...}
    disconnected_front = box OR {box1, box2, ...}
    disconnected_left = box OR {box1, box2, ...}
    disconnected_back = box OR {box1, box2, ...}
    disconnected_right = box OR {box1, box2, ...}
    disconnected = box OR {box1, box2, ...} -- when there is *no* neighbor
    disconnected_sides = box OR {box1, box2, ...} -- when there are *no*
                                                  -- neighbors to the sides
}

A box is defined as:

{x1, y1, z1, x2, y2, z2}

A box of a regular node would look like:

{-0.5, -0.5, -0.5, 0.5, 0.5, 0.5},

To avoid collision issues, keep each value within the range of +/- 1.45. This also applies to leveled nodeboxes, where the final height shall not exceed this soft limit.

Map terminology and coordinates

Nodes, mapblocks, mapchunks

A 'node' is the fundamental cubic unit of a world and appears to a player as roughly 1x1x1 meters in size.

A 'mapblock' (often abbreviated to 'block') is 16x16x16 nodes and is the fundamental region of a world that is stored in the world database, sent to clients and handled by many parts of the engine. 'mapblock' is preferred terminology to 'block' to help avoid confusion with 'node', however 'block' often appears in the API.

A 'mapchunk' (sometimes abbreviated to 'chunk') is usually 5x5x5 mapblocks (80x80x80 nodes) and is the volume of world generated in one operation by the map generator. The size in mapblocks has been chosen to optimize map generation.

Coordinates

Orientation of axes

For node and mapblock coordinates, +X is East, +Y is up, +Z is North.

Node coordinates

Almost all positions used in the API use node coordinates.

Mapblock coordinates

Occasionally the API uses 'blockpos' which refers to mapblock coordinates that specify a particular mapblock. For example blockpos (0,0,0) specifies the mapblock that extends from node position (0,0,0) to node position (15,15,15).

Converting node position to the containing blockpos

To calculate the blockpos of the mapblock that contains the node at 'nodepos', for each axis:

• blockpos = math.floor(nodepos / 16)

Converting blockpos to min/max node positions

To calculate the min/max node positions contained in the mapblock at 'blockpos', for each axis:

• Minimum: nodepos = blockpos * 16
• Maximum: nodepos = blockpos * 16 + 15

HUD

HUD element types

The position field is used for all element types. To account for differing resolutions, the position coordinates are the percentage of the screen, ranging in value from 0 to 1.

The name field is not yet used, but should contain a description of what the HUD element represents.

The direction field is the direction in which something is drawn. 0 draws from left to right, 1 draws from right to left, 2 draws from top to bottom, and 3 draws from bottom to top.

The alignment field specifies how the item will be aligned. It is a table where x and y range from -1 to 1, with 0 being central. -1 is moved to the left/up, and 1 is to the right/down. Fractional values can be used.

The offset field specifies a pixel offset from the position. Contrary to position, the offset is not scaled to screen size. This allows for some precisely positioned items in the HUD.

Note: offset will adapt to screen DPI as well as user defined scaling factor!

The z_index field specifies the order of HUD elements from back to front. Lower z-index elements are displayed behind higher z-index elements. Elements with same z-index are displayed in an arbitrary order. Default 0. Supports negative values. By convention, the following values are recommended:

• -400: Graphical effects, such as vignette
• -300: Name tags, waypoints
• -200: Wieldhand
• -100: Things that block the player's view, e.g. masks
• 0: Default. For standard in-game HUD elements like crosshair, hotbar, minimap, builtin statbars, etc.
• 100: Temporary text messages or notification icons
• 1000: Full-screen effects such as full-black screen or credits. This includes effects that cover the entire screen

If your HUD element doesn't fit into any category, pick a number between the suggested values

Below are the specific uses for fields in each type; fields not listed for that type are ignored.

image

Displays an image on the HUD.

• scale: The scale of the image, with {x = 1, y = 1} being the original texture size. The x and y fields apply to the respective axes. Positive values scale the source image. Negative values represent percentages relative to screen dimensions. Example: {x = -20, y = 3} means the image will be drawn 20% of screen width wide, and 3 times as high as the source image is.
• text: The name of the texture that is displayed.
• alignment: The alignment of the image.
• offset: offset in pixels from position.

text

Displays text on the HUD.

• scale: Defines the bounding rectangle of the text. A value such as {x=100, y=100} should work.
• text: The text to be displayed in the HUD element. Supports core.translate (always) and core.colorize (since protocol version 44)
• number: An integer containing the RGB value of the color used to draw the text. Specify 0xFFFFFF for white text, 0xFF0000 for red, and so on.
• alignment: The alignment of the text.
• offset: offset in pixels from position.
• size: size of the text. The player-set font size is multiplied by size.x (y value isn't used).
• style: determines font style Bitfield with 1 = bold, 2 = italic, 4 = monospace

statbar

Displays a horizontal bar made up of half-images with an optional background.

• text: The name of the texture to use.
• text2: Optional texture name to enable a background / "off state" texture (useful to visualize the maximal value). Both textures must have the same size.
• number: The number of half-textures that are displayed. If odd, will end with a vertically center-split texture.
• item: Same as number but for the "off state" texture
• direction: To which direction the images will extend to
• offset: offset in pixels from position.
• size: If used, will force full-image size to this value (override texture pack image size)

inventory

• text: The name of the inventory list to be displayed.
• number: Number of items in the inventory to be displayed.
• item: Position of item that is selected.
• direction: Direction the list will be displayed in
• offset: offset in pixels from position.
• alignment: The alignment of the inventory. Aligned at the top left corner if not specified.

hotbar

• direction: Direction the list will be displayed in
• offset: offset in pixels from position.
• alignment: The alignment of the inventory.

waypoint

Displays distance to selected world position.

• name: The name of the waypoint.
• text: Distance suffix. Can be blank.
• precision: Waypoint precision, integer >= 0. Defaults to 10. If set to 0, distance is not shown. Shown value is floor(distance*precision)/precision. When the precision is an integer multiple of 10, there will be log_10(precision) digits after the decimal point. precision = 1000, for example, will show 3 decimal places (eg: 0.999). precision = 2 will show multiples of 0.5; precision = 5 will show multiples of 0.2 and so on: precision = n will show multiples of 1/n
• number: An integer containing the RGB value of the color used to draw the text.
• world_pos: World position of the waypoint.
• offset: offset in pixels from position.
• alignment: The alignment of the waypoint.

image_waypoint

Same as image, but does not accept a position; the position is instead determined by world_pos, the world position of the waypoint.

• scale: The scale of the image, with {x = 1, y = 1} being the original texture size. The x and y fields apply to the respective axes. Positive values scale the source image. Negative values represent percentages relative to screen dimensions. Example: {x = -20, y = 3} means the image will be drawn 20% of screen width wide, and 3 times as high as the source image is.
• text: The name of the texture that is displayed.
• alignment: The alignment of the image.
• world_pos: World position of the waypoint.
• offset: offset in pixels from position.

compass

Displays an image oriented or translated according to current heading direction.

• size: The size of this element. Negative values represent percentage of the screen; e.g. x=-100 means 100% (width).
• scale: Scale of the translated image (used only for dir = 2 or dir = 3).
• text: The name of the texture to use.
• alignment: The alignment of the image.
• offset: Offset in pixels from position.
• direction: How the image is rotated/translated:
  • 0 - Rotate as heading direction
  • 1 - Rotate in reverse direction
  • 2 - Translate as landscape direction
  • 3 - Translate in reverse direction

If translation is chosen, texture is repeated horizontally to fill the whole element.

minimap

Displays a minimap on the HUD.

• size: Size of the minimap to display. Minimap should be a square to avoid distortion.
  • Negative values represent percentages of the screen. If either x or y is specified as a percentage, the resulting pixel size will be used for both x and y. Example: On a 1920x1080 screen, {x = 0, y = -25} will result in a 270x270 minimap.
  • Negative values are supported starting with protocol version 45.
• alignment: The alignment of the minimap.
• offset: offset in pixels from position.

Representations of simple things

Vector (ie. a position)

vector.new(x, y, z)

See [Spatial Vectors] for details.

pointed_thing

• {type="nothing"}
• {type="node", under=pos, above=pos}
  • Indicates a pointed node selection box.
  • under refers to the node position behind the pointed face.
  • above refers to the node position in front of the pointed face.
• {type="object", ref=ObjectRef}

Exact pointing location (currently only Raycast supports these fields):

• pointed_thing.intersection_point: The absolute world coordinates of the point on the selection box which is pointed at. May be in the selection box if the pointer is in the box too.
• pointed_thing.box_id: The ID of the pointed selection box (counting starts from 1).
• pointed_thing.intersection_normal: Unit vector, points outwards of the selected selection box. This specifies which face is pointed at. Is a null vector vector.zero() when the pointer is inside the selection box. For entities with rotated selection boxes, this will be rotated properly by the entity's rotation - it will always be in absolute world space.

Flag Specifier Format

Flags using the standardized flag specifier format can be specified in either of two ways, by string or table.

The string format is a comma-delimited set of flag names; whitespace and unrecognized flag fields are ignored. Specifying a flag in the string sets the flag, and specifying a flag prefixed by the string "no" explicitly clears the flag from whatever the default may be.

In addition to the standard string flag format, the schematic flags field can also be a table of flag names to boolean values representing whether or not the flag is set. Additionally, if a field with the flag name prefixed with "no" is present, mapped to a boolean of any value, the specified flag is unset.

E.g. A flag field of value

{place_center_x = true, place_center_y=false, place_center_z=true}

is equivalent to

{place_center_x = true, noplace_center_y=true, place_center_z=true}

which is equivalent to

"place_center_x, noplace_center_y, place_center_z"

or even

"place_center_x, place_center_z"

since, by default, no schematic attributes are set.

Items

Items are things that can be held by players, dropped in the map and stored in inventories. Items come in the form of item stacks, which are collections of equal items that occupy a single inventory slot.

Item types

There are three kinds of items: nodes, tools and craftitems.

• Node: Placeable item form of a node in the world's voxel grid
• Tool: Has a changeable wear property but cannot be stacked
• Craftitem: Has no special properties

Every registered node (the voxel in the world) has a corresponding item form (the thing in your inventory) that comes along with it. This item form can be placed which will create a node in the world (by default). Both the 'actual' node and its item form share the same identifier. For all practical purposes, you can treat the node and its item form interchangeably. We usually just say 'node' to the item form of the node as well.

Note the definition of tools is purely technical. The only really unique thing about tools is their wear, and that's basically it. Beyond that, you can't make any gameplay-relevant assumptions about tools or non-tools. It is perfectly valid to register something that acts as tool in a gameplay sense as a craftitem, and vice-versa.

Craftitems can be used for items that neither need to be a node nor a tool.

Amount and wear

All item stacks have an amount between 0 and 65535. It is 1 by default. Tool item stacks cannot have an amount greater than 1.

Tools use a wear (damage) value ranging from 0 to 65535. The value 0 is the default and is used for unworn tools. The values 1 to 65535 are used for worn tools, where a higher value stands for a higher wear. Non-tools technically also have a wear property, but it is always 0. There is also a special 'toolrepair' crafting recipe that is only available to tools.

Item formats

Items and item stacks can exist in three formats: Serializes, table format and ItemStack.

When an item must be passed to a function, it can usually be in any of these formats.

Serialized

This is called "stackstring" or "itemstring". It is a simple string with 1-4 components:

1. Full item identifier ("item name")
2. Optional amount
3. Optional wear value
4. Optional item metadata

Syntax:

<identifier> [<amount>[ <wear>[ <metadata>]]]

Examples:

• "default:apple": 1 apple
• "default:dirt 5": 5 dirt
• "default:pick_stone": a new stone pickaxe
• "default:pick_wood 1 21323": a wooden pickaxe, ca. 1/3 worn out
• [[default:pick_wood 1 21323 "\u0001description\u0002My worn out pick\u0003"]]:
  • a wooden pickaxe from the default mod,
  • amount must be 1 (pickaxe is a tool), ca. 1/3 worn out (it's a tool),
  • with the description field set to "My worn out pick" in its metadata
• [[default:dirt 5 0 "\u0001description\u0002Special dirt\u0003"]]:
  • analogous to the above example
  • note how the wear is set to 0 as dirt is not a tool

You should ideally use the ItemStack format to build complex item strings (especially if they use item metadata) without relying on the serialization format. Example:

local stack = ItemStack("default:pick_wood")
stack:set_wear(21323)
stack:get_meta():set_string("description", "My worn out pick")
local itemstring = stack:to_string()

Additionally the methods core.itemstring_with_palette(item, palette_index) and core.itemstring_with_color(item, colorstring) may be used to create item strings encoding color information in their metadata.

Table format

Examples:

5 dirt nodes:

{name="default:dirt", count=5, wear=0, metadata=""}

A wooden pick about 1/3 worn out:

{name="default:pick_wood", count=1, wear=21323, metadata=""}

An apple:

{name="default:apple", count=1, wear=0, metadata=""}

ItemStack

A native C++ format with many helper methods. Useful for converting between formats. See the [Class reference] section for details.

Groups

In a number of places, there is a group table. Groups define the properties of a thing (item, node, armor of entity, tool capabilities) in such a way that the engine and other mods can can interact with the thing without actually knowing what the thing is.

Usage

Groups are stored in a table, having the group names with keys and the group ratings as values. Group ratings are integer values within the range [-32767, 32767]. For example:

-- Default dirt
groups = {crumbly=3, soil=1}

-- A more special dirt-kind of thing
groups = {crumbly=2, soil=1, level=2, outerspace=1}

Groups always have a rating associated with them. If there is no useful meaning for a rating for an enabled group, it shall be 1.

When not defined, the rating of a group defaults to 0. Thus when you read groups, you must interpret nil and 0 as the same value, 0.

You can read the rating of a group for an item or a node by using

core.get_item_group(itemname, groupname)

Groups of items

Groups of items can define what kind of an item it is (e.g. wool).

Groups of nodes

In addition to the general item things, groups are used to define whether a node is destroyable and how long it takes to destroy by a tool.

Groups of entities

For entities, groups are, as of now, used only for calculating damage. The rating is the percentage of damage caused by items with this damage group. See [Entity damage mechanism].

object:get_armor_groups() --> a group-rating table (e.g. {fleshy=100})
object:set_armor_groups({fleshy=30, cracky=80})

Groups of tool capabilities

Groups in tool capabilities define which groups of nodes and entities they are effective towards.

Groups in crafting recipes

In crafting recipes, you can specify a group as an input item. This means that any item in that group will be accepted as input.

The basic syntax is:

"group:<group_name>"

For example, "group:meat" will accept any item in the meat group.

It is also possible to require an input item to be in multiple groups at once. The syntax for that is:

"group:<group_name_1>,<group_name_2>,(...),<group_name_n>"

For example, "group:leaves,birch,trimmed" accepts any item which is member of all the groups leaves and birch and trimmed.

An example recipe: Craft a raw meat soup from any meat, any water and any bowl:

{
    output = "food:meat_soup_raw",
    recipe = {
        {"group:meat"},
        {"group:water"},
        {"group:bowl"},
    },
}

Another example: Craft red wool from white wool and red dye (here, "red dye" is defined as any item which is member of both the groups dye and basecolor_red).

{
    type = "shapeless",
    output = "wool:red",
    recipe = {"wool:white", "group:dye,basecolor_red"},
}

Special groups

The asterisk (*) after a group name describes that there is no engine functionality bound to it, and implementation is left up as a suggestion to games.

Node and item groups

• not_in_creative_inventory: (*) Special group for inventory mods to indicate that the item should be hidden in item lists.

Node-only groups

• attached_node: the node is 'attached' to a neighboring node. It checks whether the node it is attached to is walkable. If it isn't, the node will drop as an item.
  • 1: if the node is wallmounted, the node is attached in the wallmounted direction. Otherwise, the node is attached to the node below.
  • 2: if the node is facedir or 4dir, the facedir or 4dir direction is checked. No effect for other nodes. Note: The "attaching face" of this node is tile no. 5 (back face).
  • 3: the node is always attached to the node below.
  • 4: the node is always attached to the node above.
• bouncy: value is bounce speed in percent. If positive, jump/sneak on floor impact will increase/decrease bounce height. Negative value is the same bounciness, but non-controllable.
• connect_to_raillike: makes nodes of raillike drawtype with same group value connect to each other
• dig_immediate: Player can always pick up node without reducing tool wear
  • 2: the node always gets the digging time 0.5 seconds (rail, sign)
  • 3: the node always gets the digging time 0 seconds (torch)
• disable_jump: Player (and possibly other things) cannot jump from node or if their feet are in the node. Note: not supported for new_move = false
• disable_descend: Player (and possibly other things) cannot actively descend in node using Sneak or Aux1 key (for liquids and climbable nodes only). Note: not supported for new_move = false
• fall_damage_add_percent: modifies the fall damage suffered when hitting the top of this node. There's also an armor group with the same name. The final player damage is determined by the following formula: ```lua damage = collision speed
  • ((node_fall_damage_add_percent + 100) / 100) -- node group
  • ((player_fall_damage_add_percent + 100) / 100) -- player armor group
  • (14) -- constant tolerance ``` Negative damage values are discarded as no damage.
• falling_node: if there is no walkable block under the node it will fall
• float: the node will not fall through liquids (liquidtype ~= "none")
  • A liquid source with groups = {falling_node = 1, float = 1} will fall through flowing liquids.
• level: Can be used to give an additional sense of progression in the game.
  • A larger level will cause e.g. a weapon of a lower level make much less damage, and get worn out much faster, or not be able to get drops from destroyed nodes.
  • 0 is something that is directly accessible at the start of gameplay
  • There is no upper limit
  • See also: leveldiff in [Tool Capabilities]
• slippery: Players and items will slide on the node. Slipperiness rises steadily with slippery value, starting at 1.

Tool-only groups

• disable_repair: If set to 1 for a tool, it cannot be repaired using the "toolrepair" crafting recipe

ObjectRef armor groups

• immortal: Skips all damage and breath handling for an object. This group will also hide the integrated HUD status bars for players. It is automatically set to all players when damage is disabled on the server and cannot be reset (subject to change).
• fall_damage_add_percent: Modifies the fall damage suffered by players when they hit the ground. It is analog to the node group with the same name. See the node group above for the exact calculation.
• punch_operable: For entities; disables the regular damage mechanism for players punching it by hand or a non-tool item, so that it can do something else than take damage.

Known damage and digging time defining groups

• crumbly: dirt, sand
• cracky: tough but crackable stuff like stone.
• snappy: something that can be cut using things like scissors, shears, bolt cutters and the like, e.g. leaves, small plants, wire, sheets of metal
• choppy: something that can be cut using force; e.g. trees, wooden planks
• fleshy: Living things like animals and the player. This could imply some blood effects when hitting.
• explody: Especially prone to explosions
• oddly_breakable_by_hand: Can be added to nodes that shouldn't logically be breakable by the hand but are. Somewhat similar to dig_immediate, but times are more like {[1]=3.50,[2]=2.00,[3]=0.70} and this does not override the digging speed of an item if it can dig at a faster speed than this suggests for the hand.

Examples of custom groups

Item groups are often used for defining, well, groups of items.

• meat: any meat-kind of a thing (rating might define the size or healing ability or be irrelevant -- it is not defined as of yet)
• eatable: anything that can be eaten. Rating might define HP gain in half hearts.
• flammable: can be set on fire. Rating might define the intensity of the fire, affecting e.g. the speed of the spreading of an open fire.
• wool: any wool (any origin, any color)
• metal: any metal
• weapon: any weapon
• heavy: anything considerably heavy

Digging time calculation specifics

Groups such as crumbly, cracky and snappy are used for this purpose. Rating is 1, 2 or 3. A higher rating for such a group implies faster digging time.

The level group is used to limit the toughness of nodes an item capable of digging can dig and to scale the digging times / damage to a greater extent.

Please do understand this, otherwise you cannot use the system to it's full potential.

Items define their properties by a list of parameters for groups. They cannot dig other groups; thus it is important to use a standard bunch of groups to enable interaction with items.

Tool Capabilities

'Tool capabilities' is a property of items that defines two things:

1) Which nodes it can dig and how fast 2) Which objects it can hurt by punching and by how much

Tool capabilities are available for all items, not just tools. But only tools can receive wear from digging and punching.

Missing or incomplete tool capabilities will default to the player's hand.

Tool capabilities definition

Tool capabilities define:

• Full punch interval
• Maximum drop level
• For an arbitrary list of node groups:
  • Uses (until the tool breaks)
  • Maximum level (usually 0, 1, 2 or 3)
  • Digging times
• Damage groups
• Punch attack uses (until the tool breaks)

Full punch interval full_punch_interval

When used as a weapon, the item will do full damage if this time is spent between punches. If e.g. half the time is spent, the item will do half damage.

Maximum drop level max_drop_level

Suggests the maximum level of node, when dug with the item, that will drop its useful item. (e.g. iron ore to drop a lump of iron).

This value is not used in the engine; it is the responsibility of the game/mod code to implement this.

Uses uses (tools only)

Determines how many uses the tool has when it is used for digging a node, of this group, of the maximum level. The maximum supported number of uses is 65535. The special number 0 is used for infinite uses. For lower leveled nodes, the use count is multiplied by 3^leveldiff. leveldiff is the difference of the tool's maxlevel groupcaps and the node's level group. The node cannot be dug if leveldiff is less than zero.

• uses=10, leveldiff=0: actual uses: 10
• uses=10, leveldiff=1: actual uses: 30
• uses=10, leveldiff=2: actual uses: 90

For non-tools, this has no effect.

Maximum level maxlevel

Tells what is the maximum level of a node of this group that the item will be able to dig.

Digging times times

List of digging times for different ratings of the group, for nodes of the maximum level.

For example, as a Lua table, times={[2]=2.00, [3]=0.70}. This would result in the item to be able to dig nodes that have a rating of 2 or 3 for this group, and unable to dig the rating 1, which is the toughest. Unless there is a matching group that enables digging otherwise.

If the result digging time is 0, a delay of 0.15 seconds is added between digging nodes. If the player releases LMB after digging, this delay is set to 0, i.e. players can more quickly click the nodes away instead of holding LMB.

This extra delay is not applied in case of a digging time between 0 and 0.15, so a digging time of 0.01 is actually faster than a digging time of 0.

Damage groups

List of damage for groups of entities. See [Entity damage mechanism].

Punch attack uses (tools only)

Determines how many uses (before breaking) the tool has when dealing damage to an object, when the full punch interval (see above) was always waited out fully.

Wear received by the tool is proportional to the time spent, scaled by the full punch interval.

For non-tools, this has no effect.

Example definition of the capabilities of an item

tool_capabilities = {
    groupcaps={
        crumbly={maxlevel=2, uses=20, times={[1]=1.60, [2]=1.20, [3]=0.80}}
    },
}

This makes the item capable of digging nodes that fulfill both of these:

• Have the crumbly group
• Have a level group less or equal to 2

Table of resulting digging times:

crumbly        0     1     2     3     4  <- level
     ->  0     -     -     -     -     -
         1  0.80  1.60  1.60     -     -
         2  0.60  1.20  1.20     -     -
         3  0.40  0.80  0.80     -     -

level diff:    2     1     0    -1    -2

Table of resulting tool uses:

->  0     -     -     -     -     -
    1   180    60    20     -     -
    2   180    60    20     -     -
    3   180    60    20     -     -

Notes:

• At crumbly==0, the node is not diggable.
• At crumbly==3, the level difference digging time divider kicks in and makes easy nodes to be quickly breakable.
• At level > 2, the node is not diggable, because it's level > maxlevel

Entity damage mechanism

Damage calculation:

damage = 0
foreach group in cap.damage_groups:
    damage += cap.damage_groups[group]
        * limit(actual_interval / cap.full_punch_interval, 0.0, 1.0)
        * (object.armor_groups[group] / 100.0)
        -- Where object.armor_groups[group] is 0 for inexistent values
return damage

Client predicts damage based on damage groups. Because of this, it is able to give an immediate response when an entity is damaged or dies; the response is pre-defined somehow (e.g. by defining a sprite animation) (not implemented; TODO). Currently a smoke puff will appear when an entity dies.

The group immortal completely disables normal damage.

Entities can define a special armor group, which is punch_operable. This group disables the regular damage mechanism for players punching it by hand or a non-tool item, so that it can do something else than take damage.

On the Lua side, every punch calls:

entity:on_punch(puncher, time_from_last_punch, tool_capabilities, direction,
                damage)

This should never be called directly, because damage is usually not handled by the entity itself.

• puncher is the object performing the punch. Can be nil. Should never be accessed unless absolutely required, to encourage interoperability.
• time_from_last_punch is time from last punch (by puncher) or nil.
• tool_capabilities can be nil.
• direction is a unit vector, pointing from the source of the punch to the punched object.
• damage damage that will be done to entity Return value of this function will determine if damage is done by this function (retval true) or shall be done by engine (retval false)

To punch an entity/object in Lua, call:

object:punch(puncher, time_from_last_punch, tool_capabilities, direction)

• Return value is tool wear.
• Parameters are equal to the above callback.
• If direction equals nil and puncher does not equal nil, direction will be automatically filled in based on the location of puncher.

Metadata

Node Metadata

The instance of a node in the world normally only contains the three values mentioned in [Nodes]. However, it is possible to insert extra data into a node. It is called "node metadata"; See NodeMetaRef.

Node metadata contains two things:

• A key-value store
• An inventory

Some of the values in the key-value store are handled specially:

• formspec: Defines an inventory menu that is opened with the 'place/use' key. Only works if no on_rightclick was defined for the node. See also [Formspec].
• infotext: Text shown on the screen when the node is pointed at. Line-breaks will be applied automatically. If the infotext is very long, it will be truncated.

Example:

local meta = core.get_meta(pos)

-- Set node formspec and infotext
meta:set_string("formspec",
        "size[8,9]"..
        "list[context;main;0,0;8,4;]"..
        "list[current_player;main;0,5;8,4;]")
meta:set_string("infotext", "Chest");

-- Set inventory list size of `"main"` list to 32
local inv = meta:get_inventory()
inv:set_size("main", 32)

-- Dump node metadata
print(dump(meta:to_table()))

-- Set node metadata from a metadata table
meta:from_table({
    inventory = {
        -- Set items of inventory in all 32 slots of the `"main"` list
        main = {[1] = "default:dirt", [2] = "", [3] = "", [4] = "",
                [5] = "", [6] = "", [7] = "", [8] = "", [9] = "",
                [10] = "", [11] = "", [12] = "", [13] = "",
                [14] = "default:cobble", [15] = "", [16] = "", [17] = "",
                [18] = "", [19] = "", [20] = "default:cobble", [21] = "",
                [22] = "", [23] = "", [24] = "", [25] = "", [26] = "",
                [27] = "", [28] = "", [29] = "", [30] = "", [31] = "",
                [32] = ""}
    },
    -- metadata fields
    fields = {
        formspec = "size[8,9]list[context;main;0,0;8,4;]list[current_player;main;0,5;8,4;]",
        infotext = "Chest"
    }
})

Item Metadata

Item stacks can store metadata too. See [ItemStackMetaRef].

Item metadata only contains a key-value store.

Some of the values in the key-value store are handled specially:

• description: Set the item stack's description. See also: get_description in [ItemStack]
• short_description: Set the item stack's short description. See also: get_short_description in [ItemStack]
• inventory_image: Override inventory_image
• inventory_overlay: Override inventory_overlay
• wield_image: Override wield_image
• wield_overlay: Override wield_overlay
• wield_scale: Override wield_scale, use vector.to_string
• color: A ColorString, which sets the stack's color.
• palette_index: If the item has a palette, this is used to get the current color from the palette.
• count_meta: Replace the displayed count with any string.
• count_alignment: Set the alignment of the displayed count value. This is an int value. The lowest 2 bits specify the alignment in x-direction, the 3rd and 4th bit specify the alignment in y-direction: 0 = default, 1 = left / up, 2 = middle, 3 = right / down The default currently is the same as right/down. Example: 6 = 2 + 1*4 = middle,up
• range: Overrides the pointing range Example: meta:set_float("range", 4.2)

Example:

local meta = stack:get_meta()
meta:set_string("key", "value")
print(dump(meta:to_table()))

Example manipulations of "description" and expected output behaviors:

print(ItemStack("default:pick_steel"):get_description()) --> Steel Pickaxe
print(ItemStack("foobar"):get_description()) --> Unknown Item

local stack = ItemStack("default:stone")
stack:get_meta():set_string("description", "Custom description\nAnother line")
print(stack:get_description()) --> Custom description\nAnother line
print(stack:get_short_description()) --> Custom description

stack:get_meta():set_string("short_description", "Short")
print(stack:get_description()) --> Custom description\nAnother line
print(stack:get_short_description()) --> Short

print(ItemStack("mod:item_with_no_desc"):get_description()) --> mod:item_with_no_desc

Formspec

Formspec defines a menu. This supports inventories and some of the typical widgets like buttons, checkboxes, text input fields, etc. It is a string, with a somewhat strange format.

A formspec is made out of formspec elements, which includes widgets like buttons but also can be used to set stuff like background color.

Many formspec elements have a name, which is a unique identifier which is used when the server receives user input. You must not use the name "quit" for formspec elements.

Spaces and newlines can be inserted between the blocks, as is used in the examples.

Position and size units are inventory slots unless the new coordinate system is enabled. X and Y position the formspec element relative to the top left of the menu or container. W and H are its width and height values.

If the new system is enabled, all elements have unified coordinates for all elements with no padding or spacing in between. This is highly recommended for new forms. See real_coordinates[<bool>] and Migrating to Real Coordinates.

Inventories with a player:<name> inventory location are only sent to the player named <name>.

When displaying text which can contain formspec code, e.g. text set by a player, use core.formspec_escape. For colored text you can use core.colorize.

Since formspec version 3, elements drawn in the order they are defined. All background elements are drawn before all other elements.

WARNING: do not use an element name starting with key_; those names are reserved to pass key press events to formspec!

WARNING: names and values of elements cannot contain binary data such as ASCII control characters. For values, escape sequences used by the engine are an exception to this.

WARNING: Luanti allows you to add elements to every single formspec instance using player:set_formspec_prepend(), which may be the reason backgrounds are appearing when you don't expect them to, or why things are styled differently to normal. See [no_prepend[]] and [Styling Formspecs].

Examples

Chest

size[8,9]
list[context;main;0,0;8,4;]
list[current_player;main;0,5;8,4;]

Furnace

size[8,9]
list[context;fuel;2,3;1,1;]
list[context;src;2,1;1,1;]
list[context;dst;5,1;2,2;]
list[current_player;main;0,5;8,4;]

Minecraft-like player inventory

size[8,7.5]
image[1,0.6;1,2;player.png]
list[current_player;main;0,3.5;8,4;]
list[current_player;craft;3,0;3,3;]
list[current_player;craftpreview;7,1;1,1;]

Version History

• Formspec version 1 (pre-5.1.0):
  • (too much)
• Formspec version 2 (5.1.0):
  • Forced real coordinates
  • background9[]: 9-slice scaling parameters
• Formspec version 3 (5.2.0):
  • Formspec elements are drawn in the order of definition
  • bgcolor[]: use 3 parameters (bgcolor, formspec (now an enum), fbgcolor)
  • box[] and image[] elements enable clipping by default
  • new element: scroll_container[]
• Formspec version 4 (5.4.0):
  • Allow dropdown indexing events
• Formspec version 5 (5.5.0):
  • Added padding[] element
• Formspec version 6 (5.6.0):
  • Add nine-slice images, animated_image, and fgimg_middle
• Formspec version 7 (5.8.0):
  • style[]: Add focused state for buttons
  • Add field_enter_after_edit[] (experimental)
• Formspec version 8 (5.10.0)
  • scroll_container[]: content padding parameter

Elements

formspec_version[<version>]

• Set the formspec version to a certain number. If not specified, version 1 is assumed.
• Must be specified before size element.
• Clients older than this version can neither show newer elements nor display elements with new arguments correctly.
• Available since feature formspec_version_element.
• See also: [Version History]

size[<W>,<H>,<fixed_size>]

• Define the size of the menu in inventory slots
• fixed_size: true/false (optional)
• deprecated: invsize[<W>,<H>;]

position[<X>,<Y>]

• Must be used after size element.
• Defines the position on the game window of the formspec's anchor point.
• For X and Y, 0.0 and 1.0 represent opposite edges of the game window, for example:
  • [0.0, 0.0] sets the position to the top left corner of the game window.
  • [1.0, 1.0] sets the position to the bottom right of the game window.
• Defaults to the center of the game window [0.5, 0.5].

anchor[<X>,<Y>]

• Must be used after both size and position (if present) elements.
• Defines the location of the anchor point within the formspec.
• For X and Y, 0.0 and 1.0 represent opposite edges of the formspec, for example:
  • [0.0, 1.0] sets the anchor to the bottom left corner of the formspec.
  • [1.0, 0.0] sets the anchor to the top right of the formspec.

• Defaults to the center of the formspec [0.5, 0.5].

• position and anchor elements need suitable values to avoid a formspec extending off the game window due to particular game window sizes.

padding[<X>,<Y>]

• Must be used after the size, position, and anchor elements (if present).
• Defines how much space is padded around the formspec if the formspec tries to increase past the size of the screen and coordinates have to be shrunk.
• For X and Y, 0.0 represents no padding (the formspec can touch the edge of the screen), and 0.5 represents half the screen (which forces the coordinate size to 0). If negative, the formspec can extend off the edge of the screen.
• Defaults to [0.05, 0.05].

no_prepend[]

• Must be used after the size, position, anchor, and padding elements (if present).
• Disables player:set_formspec_prepend() from applying to this formspec.

real_coordinates[<bool>]

• INFORMATION: Enable it automatically using formspec_version version 2 or newer.
• When set to true, all following formspec elements will use the new coordinate system.
• If used immediately after size, position, anchor, and no_prepend elements (if present), the form size will use the new coordinate system.
• Note: Formspec prepends are not affected by the coordinates in the main form. They must enable it explicitly.
• For information on converting forms to the new coordinate system, see Migrating to Real Coordinates.

container[<X>,<Y>]

• Start of a container block, moves all physical elements in the container by (X, Y).
• Must have matching container_end
• Containers can be nested, in which case the offsets are added (child containers are relative to parent containers)

container_end[]

• End of a container, following elements are no longer relative to this container.

scroll_container[<X>,<Y>;<W>,<H>;<scrollbar name>;<orientation>;<scroll factor>;<content padding>]

• Start of a scroll_container block. All contained elements will ...
  • take the scroll_container coordinate as position origin,
  • be additionally moved by the current value of the scrollbar with the name scrollbar name times scroll factor along the orientation orientation and
  • be clipped to the rectangle defined by X, Y, W and H.
• orientation: possible values are vertical and horizontal.
• scroll factor: optional, defaults to 0.1.
• content padding: (optional), in formspec coordinate units
  • If specified, the scrollbar properties max and thumbsize are calculated automatically based on the content size plus content padding at the end of the container. min is set to 0.
  • Negative scroll factor is not supported.
  • When active, scrollbaroptions[] has no effect on the affected properties.
  • Defaults to empty value (= disabled).
• Nesting is possible.
• Some elements might work a little different if they are in a scroll_container.
• Note: If you want the scroll_container to actually work, you also need to add a scrollbar element with the specified name. Furthermore, it is highly recommended to use a scrollbaroptions element on this scrollbar.

scroll_container_end[]

• End of a scroll_container, following elements are no longer bound to this container.

list[<inventory location>;<list name>;<X>,<Y>;<W>,<H>;<starting item index>]

• Show an inventory list if it has been sent to the client.
• If the inventory list changes (eg. it didn't exist before, it's resized, or its items are moved) while the formspec is open, the formspec element may (but is not guaranteed to) adapt to the new inventory list.
• Item slots are drawn in a grid from left to right, then up to down, ordered according to the slot index.
• W and H are in inventory slots, not in coordinates.
• starting item index (Optional): The index of the first (upper-left) item to draw. Indices start at 0. Default is 0.
• The number of shown slots is the minimum of W*H and the inventory list's size minus starting item index.
• Note: With the new coordinate system, the spacing between inventory slots is one-fourth the size of an inventory slot by default. Also see [Styling Formspecs] for changing the size of slots and spacing.

listring[<inventory location>;<list name>]

• Appends to an internal ring of inventory lists.
• Shift-clicking on items in one element of the ring will send them to the next inventory list inside the ring
• The first occurrence of an element inside the ring will determine the inventory where items will be sent to

listring[]

• Shorthand for doing listring[<inventory location>;<list name>] for the last two inventory lists added by list[...]

listcolors[<slot_bg_normal>;<slot_bg_hover>]

• Sets background color of slots as ColorString
• Sets background color of slots on mouse hovering

listcolors[<slot_bg_normal>;<slot_bg_hover>;<slot_border>]

• Sets background color of slots as ColorString
• Sets background color of slots on mouse hovering
• Sets color of slots border

listcolors[<slot_bg_normal>;<slot_bg_hover>;<slot_border>;<tooltip_bgcolor>;<tooltip_fontcolor>]

• Sets background color of slots as ColorString
• Sets background color of slots on mouse hovering
• Sets color of slots border
• Sets default background color of tooltips
• Sets default font color of tooltips

tooltip[<gui_element_name>;<tooltip_text>;<bgcolor>;<fontcolor>]

• Adds tooltip for an element
• bgcolor tooltip background color as ColorString (optional)
• fontcolor tooltip font color as ColorString (optional)

tooltip[<X>,<Y>;<W>,<H>;<tooltip_text>;<bgcolor>;<fontcolor>]

• Adds tooltip for an area. Other tooltips will take priority when present.
• bgcolor tooltip background color as ColorString (optional)
• fontcolor tooltip font color as ColorString (optional)

image[<X>,<Y>;<W>,<H>;<texture name>;<middle>]

• Show an image.
• middle (optional): Makes the image render in 9-sliced mode and defines the middle rect.
  • Requires formspec version >= 6.
  • See background9[] documentation for more information.

animated_image[<X>,<Y>;<W>,<H>;<name>;<texture name>;<frame count>;<frame duration>;<frame start>;<middle>]

• Show an animated image. The image is drawn like a "vertical_frames" tile animation (See [Tile animation definition]), but uses a frame count/duration for simplicity
• name: Element name to send when an event occurs. The event value is the index of the current frame.
• texture name: The image to use.
• frame count: The number of frames animating the image.
• frame duration: Milliseconds between each frame. 0 means the frames don't advance.
• frame start (optional): The index of the frame to start on. Default 1.
• middle (optional): Makes the image render in 9-sliced mode and defines the middle rect.
  • Requires formspec version >= 6.
  • See background9[] documentation for more information.

model[<X>,<Y>;<W>,<H>;<name>;<mesh>;<textures>;<rotation>;<continuous>;<mouse control>;<frame loop range>;<animation speed>]

• Show a mesh model.
• name: Element name that can be used for styling
• mesh: The mesh model to use.
• textures: The mesh textures to use according to the mesh materials. Texture names must be separated by commas.
• rotation (Optional): Initial rotation of the camera, format x,y. The axes are euler angles in degrees.
• continuous (Optional): Whether the rotation is continuous. Default false.
• mouse control (Optional): Whether the model can be controlled with the mouse. Default true.
• frame loop range (Optional): Range of the animation frames.
  • Defaults to the full range of all available frames.
  • Syntax: <begin>,<end>
• animation speed (Optional): Sets the animation speed. Default 0 FPS.

item_image[<X>,<Y>;<W>,<H>;<item name>]

• Show an inventory image of registered item/node

bgcolor[<bgcolor>;<fullscreen>;<fbgcolor>]

• Sets background color of formspec.
• bgcolor and fbgcolor (optional) are ColorStrings, they define the color of the non-fullscreen and the fullscreen background.
• fullscreen (optional) can be one of the following:
  • false: Only the non-fullscreen background color is drawn. (default)
  • true: Only the fullscreen background color is drawn.
  • both: The non-fullscreen and the fullscreen background color are drawn.
  • neither: No background color is drawn.
• Note: Leave a parameter empty to not modify the value.
• Note: fbgcolor, leaving parameters empty and values for fullscreen that are not bools are only available since formspec version 3.

background[<X>,<Y>;<W>,<H>;<texture name>]

• Example for formspec 8x4 in 16x resolution: image shall be sized 8 times 16px times 4 times 16px.

background[<X>,<Y>;<W>,<H>;<texture name>;<auto_clip>]

• Example for formspec 8x4 in 16x resolution: image shall be sized 8 times 16px times 4 times 16px
• If auto_clip is true, the background is clipped to the formspec size (x and y are used as offset values, w and h are ignored)

background9[<X>,<Y>;<W>,<H>;<texture name>;<auto_clip>;<middle>]

• 9-sliced background. See https://en.wikipedia.org/wiki/9-slice_scaling
• Middle is a rect which defines the middle of the 9-slice.
  • x - The middle will be x pixels from all sides.
  • x,y - The middle will be x pixels from the horizontal and y from the vertical.
  • x,y,x2,y2 - The middle will start at x,y, and end at x2, y2. Negative x2 and y2 values will be added to the width and height of the texture, allowing it to be used as the distance from the far end.
  • All numbers in middle are integers.
• If auto_clip is true, the background is clipped to the formspec size (x and y are used as offset values, w and h are ignored)
• Available since formspec version 2

pwdfield[<X>,<Y>;<W>,<H>;<name>;<label>]

• Textual password style field; will be sent to server when a button is clicked
• When enter is pressed in field, fields.key_enter_field will be sent with the name of this field.
• With the old coordinate system, fields are a set height, but will be vertically centered on H. With the new coordinate system, H will modify the height.
• name is the name of the field as returned in fields to on_receive_fields
• label, if not blank, will be text printed on the top left above the field
• See field_close_on_enter to stop enter closing the formspec

field[<X>,<Y>;<W>,<H>;<name>;<label>;<default>]

• Textual field; will be sent to server when a button is clicked
• When enter is pressed in field, fields.key_enter_field will be sent with the name of this field.
• With the old coordinate system, fields are a set height, but will be vertically centered on H. With the new coordinate system, H will modify the height.
• name is the name of the field as returned in fields to on_receive_fields
• label, if not blank, will be text printed on the top left above the field
• default is the default value of the field
  • default may contain variable references such as ${text} which will fill the value from the metadata value text
  • Note: no extra text or more than a single variable is supported ATM.
• See field_close_on_enter to stop enter closing the formspec

field[<name>;<label>;<default>]

• As above, but without position/size units
• When enter is pressed in field, fields.key_enter_field will be sent with the name of this field.
• Special field for creating simple forms, such as sign text input
• Must be used without a size[] element
• A "Proceed" button will be added automatically
• See field_close_on_enter to stop enter closing the formspec

field_enter_after_edit[<name>;<enter_after_edit>]

• Experimental, may be subject to change or removal at any time.
• Only affects Android clients.
• <name> is the name of the field.
• If <enter_after_edit> is true, pressing the "Done" button in the Android text input dialog will simulate an Enter keypress.
• Defaults to false when not specified (i.e. no tag for a field).

field_close_on_enter[<name>;<close_on_enter>]

• <name> is the name of the field.
• If <close_on_enter> is false, pressing Enter in the field will submit the form but not close it.
• Defaults to true when not specified (i.e. no tag for a field).

textarea[<X>,<Y>;<W>,<H>;<name>;<label>;<default>]

• Same as fields above, but with multi-line input
• If the text overflows, a vertical scrollbar is added.
• If the name is empty, the textarea is read-only and the background is not shown, which corresponds to a multi-line label.

label[<X>,<Y>;<label>]

• The label formspec element displays the text set in label at the specified position.
• Note: If the new coordinate system is enabled, labels are positioned from the center of the text, not the top.
• The text is displayed directly without automatic line breaking, so label should not be used for big text chunks. Newlines can be used to make labels multiline.
• Note: With the new coordinate system, newlines are spaced with half a coordinate. With the old system, newlines are spaced 2/5 of an inventory slot.

hypertext[<X>,<Y>;<W>,<H>;<name>;<text>]

• Displays a static formatted text with hyperlinks.
• Note: This element is currently unstable and subject to change.
• x, y, w and h work as per field
• name is the name of the field as returned in fields to on_receive_fields in case of action in text.
• text is the formatted text using Markup Language described below.

vertlabel[<X>,<Y>;<label>]

• Textual label drawn vertically
• label is the text on the label
• Note: If the new coordinate system is enabled, vertlabels are positioned from the center of the text, not the left.

button[<X>,<Y>;<W>,<H>;<name>;<label>]

• Clickable button. When clicked, fields will be sent.
• With the old coordinate system, buttons are a set height, but will be vertically centered on H. With the new coordinate system, H will modify the height.
• label is the text on the button

button_url[<X>,<Y>;<W>,<H>;<name>;<label>;<url>]

• Clickable button. When clicked, fields will be sent and the user will be given the option to open the URL in a browser.
• With the old coordinate system, buttons are a set height, but will be vertically centered on H. With the new coordinate system, H will modify the height.
• To make this into an image_button, you can use formspec styling.
• label is the text on the button.
• url must be a valid web URL, starting with http:// or https://.

image_button[<X>,<Y>;<W>,<H>;<texture name>;<name>;<label>]

• texture name is the filename of an image
• Note: Height is supported on both the old and new coordinate systems for image_buttons.

image_button[<X>,<Y>;<W>,<H>;<texture name>;<name>;<label>;<noclip>;<drawborder>;<pressed texture name>]

• texture name is the filename of an image
• noclip=true means the image button doesn't need to be within specified formsize.
• drawborder: draw button border or not
• pressed texture name is the filename of an image on pressed state

item_image_button[<X>,<Y>;<W>,<H>;<item name>;<name>;<label>]

• item name is the registered name of an item/node
• name is non-optional and must be unique, or else tooltips are broken.
• The item description will be used as the tooltip. This can be overridden with a tooltip element.

button_exit[<X>,<Y>;<W>,<H>;<name>;<label>]

• When clicked, fields will be sent and the form will quit.
• Same as button in all other respects.

button_url_exit[<X>,<Y>;<W>,<H>;<name>;<label>;<url>]

• When clicked, fields will be sent and the form will quit.
• Same as button_url in all other respects.

image_button_exit[<X>,<Y>;<W>,<H>;<texture name>;<name>;<label>]

• When clicked, fields will be sent and the form will quit.
• Same as image_button in all other respects.

textlist[<X>,<Y>;<W>,<H>;<name>;<listelem 1>,<listelem 2>,...,<listelem n>]

• Scrollable item list showing arbitrary text elements
• name fieldname sent to server on double-click value is current selected element.
• listelements can be prepended by #color in hexadecimal format RRGGBB (only).
  • if you want a listelement to start with "#" write "##".

textlist[<X>,<Y>;<W>,<H>;<name>;<listelem 1>,<listelem 2>,...,<listelem n>;<selected idx>;<transparent>]

• Scrollable itemlist showing arbitrary text elements
• name fieldname sent to server on double-click value is current selected element.
• listelements can be prepended by #RRGGBB (only) in hexadecimal format
  • if you want a listelement to start with "#" write "##"
• Index to be selected within textlist
• true/false: draw transparent background
• See also core.explode_textlist_event

tabheader[<X>,<Y>;<name>;<caption 1>,<caption 2>,...,<caption n>;<current_tab>;<transparent>;<draw_border>]

• Show a tabheader at specific position (ignores formsize)
• X and Y: position of the tabheader
• Note: Width and height are automatically chosen with this syntax
• name fieldname data is transferred to Lua
• caption 1...: name shown on top of tab
• current_tab: index of selected tab 1...
• transparent (optional): if true, tabs are semi-transparent
• draw_border (optional): if true, draw a thin line at tab base

tabheader[<X>,<Y>;<H>;<name>;<caption 1>,<caption 2>,...,<caption n>;<current_tab>;<transparent>;<draw_border>]

• Show a tabheader at specific position (ignores formsize)
• Important note: This syntax for tabheaders can only be used with the new coordinate system.
• X and Y: position of the tabheader
• H: height of the tabheader. Width is automatically determined with this syntax.
• name fieldname data is transferred to Lua
• caption 1...: name shown on top of tab
• current_tab: index of selected tab 1...
• transparent (optional): show transparent
• draw_border (optional): draw border

tabheader[<X>,<Y>;<W>,<H>;<name>;<caption 1>,<caption 2>,...,<caption n>;<current_tab>;<transparent>;<draw_border>]

• Show a tabheader at specific position (ignores formsize)
• Important note: This syntax for tabheaders can only be used with the new coordinate system.
• X and Y: position of the tabheader
• W and H: width and height of the tabheader
• name fieldname data is transferred to Lua
• caption 1...: name shown on top of tab
• current_tab: index of selected tab 1...
• transparent (optional): show transparent
• draw_border (optional): draw border

box[<X>,<Y>;<W>,<H>;<color>]

• Simple colored box
• color is color specified as a ColorString. If the alpha component is left blank, the box will be semitransparent. If the color is not specified, the box will use the options specified by its style. If the color is specified, all styling options will be ignored.

dropdown[<X>,<Y>;<W>;<name>;<item 1>,<item 2>, ...,<item n>;<selected idx>;<index event>]

• Show a dropdown field
• Important note: There are two different operation modes:
  1. handle directly on change (only changed dropdown is submitted)
  2. read the value on pressing a button (all dropdown values are available)
• X and Y: position of the dropdown
• W: width of the dropdown. Height is automatically chosen with this syntax.
• Fieldname data is transferred to Lua
• Items to be shown in dropdown
• Index of currently selected dropdown item
• index event (optional, allowed parameter since formspec version 4): Specifies the event field value for selected items.
  • true: Selected item index
  • false (default): Selected item value

dropdown[<X>,<Y>;<W>,<H>;<name>;<item 1>,<item 2>, ...,<item n>;<selected idx>;<index event>]

• Show a dropdown field
• Important note: This syntax for dropdowns can only be used with the new coordinate system.
• Important note: There are two different operation modes:
  1. handle directly on change (only changed dropdown is submitted)
  2. read the value on pressing a button (all dropdown values are available)
• X and Y: position of the dropdown
• W and H: width and height of the dropdown
• Fieldname data is transferred to Lua
• Items to be shown in dropdown
• Index of currently selected dropdown item
• index event (optional, allowed parameter since formspec version 4): Specifies the event field value for selected items.
  • true: Selected item index
  • false (default): Selected item value

checkbox[<X>,<Y>;<name>;<label>;<selected>]

• Show a checkbox
• name fieldname data is transferred to Lua
• label to be shown left of checkbox
• selected (optional): true/false
• Note: If the new coordinate system is enabled, checkboxes are positioned from the center of the checkbox, not the top.

scrollbar[<X>,<Y>;<W>,<H>;<orientation>;<name>;<value>]

• Show a scrollbar using options defined by the previous scrollbaroptions[]
• There are two ways to use it:
  1. handle the changed event (only changed scrollbar is available)
  2. read the value on pressing a button (all scrollbars are available)
• orientation: vertical/horizontal. Default horizontal.
• Fieldname data is transferred to Lua
• Value of this trackbar is set to (0-1000) by default
• See also core.explode_scrollbar_event

scrollbaroptions[opt1;opt2;...]

• Sets options for all following scrollbar[] elements
• min=<int>
  • Sets scrollbar minimum value, defaults to 0.
• max=<int>
  • Sets scrollbar maximum value, defaults to 1000. If the max is equal to the min, the scrollbar will be disabled.
• smallstep=<int>
  • Sets scrollbar step value when the arrows are clicked or the mouse wheel is scrolled.
  • If this is set to a negative number, the value will be reset to 10.
• largestep=<int>
  • Sets scrollbar step value used by page up and page down.
  • If this is set to a negative number, the value will be reset to 100.
• thumbsize=<int>
  • Sets size of the thumb on the scrollbar. Size is calculated in the number of units the thumb spans out of the range of the scrollbar values.
  • Example: If a scrollbar has a min of 1 and a max of 100, a thumbsize of 10 would span a tenth of the scrollbar space.
  • If this is set to zero or less, the value will be reset to 1.
• arrows=<show/hide/default>
  • Whether to show the arrow buttons on the scrollbar. default hides the arrows when the scrollbar gets too small, but shows them otherwise.

table[<X>,<Y>;<W>,<H>;<name>;<cell 1>,<cell 2>,...,<cell n>;<selected idx>]

• Show scrollable table using options defined by the previous tableoptions[]
• Displays cells as defined by the previous tablecolumns[]
• name: fieldname sent to server on row select or double-click
• cell 1...cell n: cell contents given in row-major order
• selected idx: index of row to be selected within table (first row = 1)
• See also core.explode_table_event

tableoptions[<opt 1>;<opt 2>;...]

• Sets options for table[]
• color=#RRGGBB
  • default text color (ColorString), defaults to #FFFFFF
• background=#RRGGBB
  • table background color (ColorString), defaults to #000000
• border=<true/false>
  • should the table be drawn with a border? (default: true)
• highlight=#RRGGBB
  • highlight background color (ColorString), defaults to #466432
• highlight_text=#RRGGBB
  • highlight text color (ColorString), defaults to #FFFFFF
• opendepth=<value>
  • all subtrees up to depth < value are open (default value = 0)
  • only useful when there is a column of type "tree"

tablecolumns[<type 1>,<opt 1a>,<opt 1b>,...;<type 2>,<opt 2a>,<opt 2b>;...]

• Sets columns for table[]
• Types: text, image, color, indent, tree
  • text: show cell contents as text
  • image: cell contents are an image index, use column options to define images. images are scaled down to fit the row height if necessary.
  • color: cell contents are a ColorString and define color of following cell.
  • indent: cell contents are a number and define indentation of following cell.
  • tree: same as indent, but user can open and close subtrees (treeview-like).
• Column options:
  • align=<value>
    • for text and image: content alignment within cells. Available values: left (default), center, right, inline
  • width=<value>
    • for text and image: minimum width in em (default: 0)
    • for indent and tree: indent width in em (default: 1.5)
  • padding=<value>: padding left of the column, in em (default 0.5). Exception: defaults to 0 for indent columns
  • tooltip=<value>: tooltip text (default: empty)
  • image column options:
    • 0=<value> sets image for image index 0
    • 1=<value> sets image for image index 1
    • 2=<value> sets image for image index 2
    • and so on; defined indices need not be contiguous. empty or non-numeric cells are treated as 0.
  • color column options:
    • span=<value>: number of following columns to affect (default: infinite).

style[<selector 1>,<selector 2>,...;<prop1>;<prop2>;...]

• Set the style for the element(s) matching selector by name.
• selector can be one of:
  • <name> - An element name. Includes *, which represents every element.
  • <name>:<state> - An element name, a colon, and one or more states.
• state is a list of states separated by the + character.
  • If a state is provided, the style will only take effect when the element is in that state.
  • All provided states must be active for the style to apply.
• Note: this must be before the element is defined.
• See [Styling Formspecs].

style_type[<selector 1>,<selector 2>,...;<prop1>;<prop2>;...]

• Set the style for the element(s) matching selector by type.
• selector can be one of:
  • <type> - An element type. Includes *, which represents every element.
  • <type>:<state> - An element type, a colon, and one or more states.
• state is a list of states separated by the + character.
  • If a state is provided, the style will only take effect when the element is in that state.
  • All provided states must be active for the style to apply.
• See [Styling Formspecs].

set_focus[<name>;<force>]

• Sets the focus to the element with the same name parameter.
• Note: This element must be placed before the element it focuses.
• force (optional, default false): By default, focus is not applied for re-sent formspecs with the same name so that player-set focus is kept. true sets the focus to the specified element for every sent formspec.
• The following elements have the ability to be focused:
  • checkbox
  • button
  • button_exit
  • image_button
  • image_button_exit
  • item_image_button
  • table
  • textlist
  • dropdown
  • field
  • pwdfield
  • textarea
  • scrollbar

Migrating to Real Coordinates

In the old system, positions included padding and spacing. Padding is a gap between the formspec window edges and content, and spacing is the gaps between items. For example, two 1x1 elements at 0,0 and 1,1 would have a spacing of 5/4 between them, and a padding of 3/8 from the formspec edge. It may be easiest to recreate old layouts in the new coordinate system from scratch.

To recreate an old layout with padding, you'll need to pass the positions and sizes through the following formula to re-introduce padding:

pos = (oldpos + 1)*spacing + padding
where
    padding = 3/8
    spacing = 5/4

You'll need to change the size[] tag like this:

size = (oldsize-1)*spacing + padding*2 + 1

A few elements had random offsets in the old system. Here is a table which shows these offsets when migrating:

Element	Position	Size	Notes
box	+0.3, +0.1	0, -0.4
button			Buttons now support height, so set h = 2 * 15/13 * 0.35, and reposition if h ~= 15/13 * 0.35 before
list			Spacing is now 0.25 for both directions, meaning lists will be taller in height
label	0, +0.3		The first line of text is now positioned centered exactly at the position specified

Styling Formspecs

Formspec elements can be themed using the style elements:

style[<name 1>,<name 2>,...;<prop1>;<prop2>;...]
style[<name 1>:<state>,<name 2>:<state>,...;<prop1>;<prop2>;...]
style_type[<type 1>,<type 2>,...;<prop1>;<prop2>;...]
style_type[<type 1>:<state>,<type 2>:<state>,...;<prop1>;<prop2>;...]

Where a prop is:

property_name=property_value

For example:

style_type[button;bgcolor=#006699]
style[world_delete;bgcolor=red;textcolor=yellow]
button[4,3.95;2.6,1;world_delete;Delete]

A name/type can optionally be a comma separated list of names/types, like so:

world_delete,world_create,world_configure
button,image_button

A * type can be used to select every element in the formspec.

Any name/type in the list can also be accompanied by a +-separated list of states, like so:

world_delete:hovered+pressed
button:pressed

States allow you to apply styles in response to changes in the element, instead of applying at all times.

Setting a property to nothing will reset it to the default value. For example:

style_type[button;bgimg=button.png;bgimg_pressed=button_pressed.png;border=false]
style[btn_exit;bgimg=;bgimg_pressed=;border=;bgcolor=red]

Supported Element Types

Some types may inherit styles from parent types.

• animated_image, inherits from image
• box
• button
• button_exit, inherits from button
• checkbox
• dropdown
• field
• image
• image_button
• item_image_button
• label
• list
• model
• pwdfield, inherits from field
• scrollbar
• tabheader
• table
• textarea
• textlist
• vertlabel, inherits from label

Valid Properties

• animated_image
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.
• box
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.
    • Defaults to false in formspec_version version 3 or higher
  • Note: colors, bordercolors, and borderwidths accept multiple input types:
    • Single value (e.g. #FF0): All corners/borders.
    • Two values (e.g. red,#FFAAFF): top-left and bottom-right,top-right and bottom-left/ top and bottom,left and right.
    • Four values (e.g. blue,#A0F,green,#FFFA): top-left/top and rotates clockwise.
    • These work similarly to CSS borders.
  • colors - ColorString. Sets the color(s) of the box corners. Default black.
  • bordercolors - ColorString. Sets the color(s) of the borders. Default black.
  • borderwidths - Integer. Sets the width(s) of the borders in pixels. If the width is negative, the border will extend inside the box, whereas positive extends outside the box. A width of zero results in no border; this is default.
• button, button_exit, image_button, item_image_button
  • alpha - boolean, whether to draw alpha in bgimg. Default true.
  • bgcolor - color, sets button tint.
  • bgcolor_hovered - color when hovered. Defaults to a lighter bgcolor when not provided.
    • This is deprecated, use states instead.
  • bgcolor_pressed - color when pressed. Defaults to a darker bgcolor when not provided.
    • This is deprecated, use states instead.
  • bgimg - standard background image. Defaults to none.
  • bgimg_hovered - background image when hovered. Defaults to bgimg when not provided.
    • This is deprecated, use states instead.
  • bgimg_middle - Makes the bgimg textures render in 9-sliced mode and defines the middle rect. See background9[] documentation for more details. This property also pads the button's content when set.
  • bgimg_pressed - background image when pressed. Defaults to bgimg when not provided.
    • This is deprecated, use states instead.
  • font - Sets font type. This is a comma separated list of options. Valid options:
    • Main font type options. These cannot be combined with each other:
    • normal: Default font
    • mono: Monospaced font
    • Font modification options. If used without a main font type, normal is used:
    • bold: Makes font bold.
    • italic: Makes font italic. Default normal.
  • font_size - Sets font size. Default is user-set. Can have multiple values:
    • <number>: Sets absolute font size to number.
    • +<number>/-<number>: Offsets default font size by number points.
    • *<number>: Multiplies default font size by number, similar to CSS em.
  • border - boolean, draw border. Set to false to hide the bevelled button pane. Default true.
  • content_offset - 2d vector, shifts the position of the button's content without resizing it.
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.
  • padding - rect, adds space between the edges of the button and the content. This value is relative to bgimg_middle.
  • sound - a sound to be played when triggered.
  • textcolor - color, default white.
• checkbox
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.
  • sound - a sound to be played when triggered.
• dropdown
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.
  • sound - a sound to be played when the entry is changed.
• field, pwdfield, textarea
  • border - set to false to hide the textbox background and border. Default true.
  • font - Sets font type. See button font property for more information.
  • font_size - Sets font size. See button font_size property for more information.
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.
  • textcolor - color. Default white.
• model
  • bgcolor - color, sets background color.
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.
    • Default to false in formspec_version version 3 or higher
• image
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.
    • Default to false in formspec_version version 3 or higher
• item_image
  • noclip - boolean, set to true to allow the element to exceed formspec bounds. Default to false.
• label, vertlabel
  • font - Sets font type. See button font property for more information.
  • font_size - Sets font size. See button font_size property for more information.
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.
• list
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.
  • size - 2d vector, sets the size of inventory slots in coordinates.
  • spacing - 2d vector, sets the space between inventory slots in coordinates.
• image_button (additional properties)
  • fgimg - standard image. Defaults to none.
  • fgimg_hovered - image when hovered. Defaults to fgimg when not provided.
    • This is deprecated, use states instead.
  • fgimg_pressed - image when pressed. Defaults to fgimg when not provided.
    • This is deprecated, use states instead.
  • fgimg_middle - Makes the fgimg textures render in 9-sliced mode and defines the middle rect. See background9[] documentation for more details.
  • NOTE: The parameters of any given image_button will take precedence over fgimg/fgimg_pressed
  • sound - a sound to be played when triggered.
• scrollbar
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.
• tabheader
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.
  • sound - a sound to be played when a different tab is selected.
  • textcolor - color. Default white.
• table, textlist
  • font - Sets font type. See button font property for more information.
  • font_size - Sets font size. See button font_size property for more information.
  • noclip - boolean, set to true to allow the element to exceed formspec bounds.

Valid States

• all elements
  • default - Equivalent to providing no states
• button, button_exit, image_button, item_image_button
  • focused - Active when button has focus
  • hovered - Active when the mouse is hovering over the element
  • pressed - Active when the button is pressed

Markup Language

Markup language used in hypertext[] elements uses tags that look like HTML tags. The markup language is currently unstable and subject to change. Use with caution. Some tags can enclose text, they open with <tagname> and close with </tagname>. Tags can have attributes, in that case, attributes are in the opening tag in form of a key/value separated with equal signs. Attribute values should be quoted using either " or '.

If you want to insert a literal greater-than, less-than, or a backslash into the text, you must escape it by preceding it with a backslash. In a quoted attribute value, you can insert a literal quote mark by preceding it with a backslash.

These are the technically basic tags but see below for usual tags. Base tags are:

<style color=... font=... size=...>...</style>

Changes the style of the text.

• color: Text color. Given color is a colorspec.
• size: Text size.
• font: Text font (mono or normal).

<global background=... margin=... valign=... color=... hovercolor=... size=... font=... halign=... >

Sets global style.

Global only styles:

• background: Text background, a colorspec or none.
• margin: Page margins in pixel.
• valign: Text vertical alignment (top, middle, bottom).

Inheriting styles (affects child elements):

• color: Default text color. Given color is a colorspec.
• hovercolor: Color of tags when mouse is over.
• size: Default text size.
• font: Default text font (mono or normal).
• halign: Default text horizontal alignment (left, right, center, justify).

This tag needs to be placed only once as it changes the global settings of the text. Anyway, if several tags are placed, each changed will be made in the order tags appear.

<tag name=... color=... hovercolor=... font=... size=...>

Defines or redefines tag style. This can be used to define new tags.

• name: Name of the tag to define or change.
• color: Text color. Given color is a colorspec.
• hovercolor: Text color when element hovered (only for action tags). Given color is a colorspec.
• size: Text size.
• font: Text font (mono or normal).

Following tags are the usual tags for text layout. They are defined by default. Other tags can be added using <tag ...> tag.

<normal>...</normal>: Normal size text

<big>...</big>: Big text

<bigger>...</bigger>: Bigger text

<center>...</center>: Centered text

<left>...</left>: Left-aligned text

<right>...</right>: Right-aligned text

<justify>...</justify>: Justified text

<mono>...</mono>: Monospaced font

<b>...</b>, <i>...</i>, <u>...</u>: Bold, italic, underline styles.

<action name=...>...</action>

Make that text a clickable text triggering an action.

• name: Name of the action (mandatory).
• url: URL to open when the action is triggered (optional).

When clicked, the formspec is send to the server. The value of the text field sent to on_player_receive_fields will be "action:" concatenated to the action name.

<img name=... float=... width=... height=...>

Draws an image which is present in the client media cache.

• name: Name of the texture (mandatory).
• float: If present, makes the image floating (left or right).
• width: Force image width instead of taking texture width.
• height: Force image height instead of taking texture height.

If only width or height given, texture aspect is kept.

<item name=... float=... width=... height=... rotate=...>

Draws an item image.

• name: Item string of the item to draw (mandatory).
• float: If present, makes the image floating (left or right).
• width: Item image width.
• height: Item image height.
• rotate: Rotate item image if set to yes or X,Y,Z. X, Y and Z being rotation speeds in percent of standard speed (-1000 to 1000). Works only if inventory_items_animations is set to true.
• angle: Angle in which the item image is shown. Value has X,Y,Z form. X, Y and Z being angles around each three axes. Works only if inventory_items_animations is set to true.

Inventory

Inventory locations

• "context": Selected node metadata (deprecated: "current_name")
• "current_player": Player to whom the menu is shown
• "player:<name>": Any player
• "nodemeta:<X>,<Y>,<Z>": Any node metadata
• "detached:<name>": A detached inventory

Player Inventory lists

• main: list containing the default inventory
• craft: list containing the craft input
• craftpreview: list containing the craft prediction
• craftresult: list containing the crafted output
• hand: list containing an override for the empty hand
  • Is not created automatically, use InvRef:set_size
  • Is only used to enhance the empty hand's tool capabilities

Custom lists can be added and deleted with InvRef:set_size(name, size) like any other inventory.

ItemStack transaction order

This list describes the situation for non-empty ItemStacks in both slots that cannot be stacked at all, hence triggering an ItemStack swap operation. Put/take callbacks on empty ItemStack are not executed.

1. The "allow take" and "allow put" callbacks are each run once for the source and destination inventory.
2. The allowed ItemStacks are exchanged.
3. The "on take" callbacks are run for the source and destination inventories
4. The "on put" callbacks are run for the source and destination inventories

Colors

ColorString

#RGB defines a color in hexadecimal format.

#RGBA defines a color in hexadecimal format and alpha channel.

#RRGGBB defines a color in hexadecimal format.

#RRGGBBAA defines a color in hexadecimal format and alpha channel.

Named colors are also supported and are equivalent to CSS Color Module Level 4. To specify the value of the alpha channel, append #A or #AA to the end of the color name (e.g. colorname#08).

ColorSpec

A ColorSpec specifies a 32-bit color. It can be written in any of the following forms:

• table form: Each element ranging from 0..255 (a, if absent, defaults to 255):
  • colorspec = {a=255, r=0, g=255, b=0}
• numerical form: The raw integer value of an ARGB8 quad:
  • colorspec = 0xFF00FF00
• string form: A ColorString (defined above):
  • colorspec = "green"

Escape sequences

Most text can contain escape sequences, that can for example color the text. There are a few exceptions: tab headers, dropdowns and vertical labels can't. The following functions provide escape sequences:

• core.get_color_escape_sequence(color):
  • color is a ColorString
  • The escape sequence sets the text color to color
• core.colorize(color, message):
  • Equivalent to: core.get_color_escape_sequence(color) .. message .. core.get_color_escape_sequence("#ffffff")
• core.get_background_escape_sequence(color)
  • color is a ColorString
  • The escape sequence sets the background of the whole text element to color. Only defined for item descriptions and tooltips.
• core.strip_foreground_colors(str)
  • Removes foreground colors added by get_color_escape_sequence.
• core.strip_background_colors(str)
  • Removes background colors added by get_background_escape_sequence.
• core.strip_colors(str)
  • Removes all color escape sequences.

Spatial Vectors

Luanti stores 3-dimensional spatial vectors in Lua as tables of 3 coordinates, and has a class to represent them (vector.*), which this chapter is about. For details on what a spatial vectors is, please refer to Wikipedia: https://en.wikipedia.org/wiki/Euclidean_vector.

Spatial vectors are used for various things, including, but not limited to:

• any 3D spatial vector (x/y/z-directions)
• Euler angles (pitch/yaw/roll in radians) (Spatial vectors have no real semantic meaning here. Therefore, most vector operations make no sense in this use case.)

Note that they are not used for:

• n-dimensional vectors where n is not 3 (ie. n=2)
• arrays of the form {num, num, num}

The API documentation may refer to spatial vectors, as produced by vector.new, by any of the following notations:

• (x, y, z) (Used rarely, and only if it's clear that it's a vector.)
• vector.new(x, y, z)
• {x=num, y=num, z=num} (Even here you are still supposed to use vector.new.)

Compatibility notes

Vectors used to be defined as tables of the form {x = num, y = num, z = num}. Since version 5.5.0, vectors additionally have a metatable to enable easier use. Note: Those old-style vectors can still be found in old mod code. Hence, mod and engine APIs still need to be able to cope with them in many places.

Manually constructed tables are deprecated and highly discouraged. This interface should be used to ensure seamless compatibility between mods and the Luanti API. This is especially important to callback function parameters and functions overwritten by mods. Also, though not likely, the internal implementation of a vector might change in the future. In your own code, or if you define your own API, you can, of course, still use other representations of vectors.

Vectors provided by API functions will provide an instance of this class if not stated otherwise. Mods should adapt this for convenience reasons.

Special properties of the class

Vectors can be indexed with numbers and allow method and operator syntax.

All these forms of addressing a vector v are valid: v[1], v[3], v.x, v[1] = 42, v.y = 13 Note: Prefer letter over number indexing for performance and compatibility reasons.

Where v is a vector and foo stands for any function name, v:foo(...) does the same as vector.foo(v, ...), apart from deprecated functionality.

tostring is defined for vectors, see vector.to_string.

The metatable that is used for vectors can be accessed via vector.metatable. Do not modify it!

All vector.* functions allow vectors {x = X, y = Y, z = Z} without metatables. Returned vectors always have a metatable set.

Common functions and methods

For the following functions (and subchapters), v, v1, v2 are vectors, p1, p2 are position vectors, s is a scalar (a number), vectors are written like this: (x, y, z):

• vector.new([a[, b, c]]):
  • Returns a new vector (a, b, c).
  • Deprecated: vector.new() does the same as vector.zero() and vector.new(v) does the same as vector.copy(v)
• vector.zero():
  • Returns a new vector (0, 0, 0).
• vector.random_direction():
  • Returns a new vector of length 1, pointing into a direction chosen uniformly at random.
• vector.copy(v):
  • Returns a copy of the vector v.
• vector.from_string(s[, init]):
  • Returns v, np, where v is a vector read from the given string s and np is the next position in the string after the vector.
  • Returns nil on failure.
  • s: Has to begin with a substring of the form "(x, y, z)". Additional spaces, leaving away commas and adding an additional comma to the end is allowed.
  • init: If given starts looking for the vector at this string index.
• vector.to_string(v):
  • Returns a string of the form "(x, y, z)".
  • tostring(v) does the same.
• vector.direction(p1, p2):
  • Returns a vector of length 1 with direction p1 to p2.
  • If p1 and p2 are identical, returns (0, 0, 0).
• vector.distance(p1, p2):
  • Returns zero or a positive number, the distance between p1 and p2.
• vector.length(v):
  • Returns zero or a positive number, the length of vector v.
• vector.normalize(v):
  • Returns a vector of length 1 with direction of vector v.
  • If v has zero length, returns (0, 0, 0).
• vector.floor(v):
  • Returns a vector, each dimension rounded down.
• vector.ceil(v):
  • Returns a vector, each dimension rounded up.
• vector.round(v):
  • Returns a vector, each dimension rounded to nearest integer.
  • At a multiple of 0.5, rounds away from zero.
• vector.sign(v, tolerance):
  • Returns a vector where math.sign was called for each component.
  • See [Helper functions] for details.
• vector.abs(v):
  • Returns a vector with absolute values for each component.
• vector.apply(v, func, ...):
  • Returns a vector where the function func has been applied to each component.
  • ... are optional arguments passed to func.
• vector.combine(v, w, func):
  • Returns a vector where the function func has combined both components of v and w for each component
• vector.equals(v1, v2):
  • Returns a boolean, true if the vectors are identical.
• vector.sort(v1, v2):
  • Returns in order minp, maxp vectors of the cuboid defined by v1, v2.
• vector.angle(v1, v2):
  • Returns the angle between v1 and v2 in radians.
• vector.dot(v1, v2):
  • Returns the dot product of v1 and v2.
• vector.cross(v1, v2):
  • Returns the cross product of v1 and v2.
• vector.offset(v, x, y, z):
  • Returns the sum of the vectors v and (x, y, z).
• vector.check(v):
  • Returns a boolean value indicating whether v is a real vector, eg. created by a vector.* function.
  • Returns false for anything else, including tables like {x=3,y=1,z=4}.
• vector.in_area(pos, min, max):
  • Returns a boolean value indicating if pos is inside area formed by min and max.
  • min and max are inclusive.
  • If min is bigger than max on some axis, function always returns false.
  • You can use vector.sort if you have two vectors and don't know which are the minimum and the maximum.
• vector.random_in_area(min, max):
  • Returns a random integer position in area formed by min and max
  • min and max are inclusive.
  • You can use vector.sort if you have two vectors and don't know which are the minimum and the maximum.

For the following functions x can be either a vector or a number:

• vector.add(v, x):
  • Returns a vector.
  • If x is a vector: Returns the sum of v and x.
  • If x is a number: Adds x to each component of v.
• vector.subtract(v, x):
  • Returns a vector.
  • If x is a vector: Returns the difference of v subtracted by x.
  • If x is a number: Subtracts x from each component of v.
• vector.multiply(v, s):
  • Returns a scaled vector.
  • Deprecated: If s is a vector: Returns the Schur product.
• vector.divide(v, s):
  • Returns a scaled vector.
  • Deprecated: If s is a vector: Returns the Schur quotient.

Operators

Operators can be used if all of the involved vectors have metatables:

• v1 == v2:
  • Returns whether v1 and v2 are identical.
• -v:
  • Returns the additive inverse of v.
• v1 + v2:
  • Returns the sum of both vectors.
  • Note: + cannot be used together with scalars.
• v1 - v2:
  • Returns the difference of v1 subtracted by v2.
  • Note: - cannot be used together with scalars.
• v * s or s * v:
  • Returns v scaled by s.
• v / s:
  • Returns v scaled by 1 / s.

Rotation-related functions

For the following functions a is an angle in radians and r is a rotation vector ({x = <pitch>, y = <yaw>, z = <roll>}) where pitch, yaw and roll are angles in radians.

• vector.rotate(v, r):
  • Applies the rotation r to v and returns the result.
  • vector.rotate(vector.new(0, 0, 1), r) and vector.rotate(vector.new(0, 1, 0), r) return vectors pointing forward and up relative to an entity's rotation r.
• vector.rotate_around_axis(v1, v2, a):
  • Returns v1 rotated around axis v2 by a radians according to the right hand rule.
• vector.dir_to_rotation(direction[, up]):
  • Returns a rotation vector for direction pointing forward using up as the up vector.
  • If up is omitted, the roll of the returned vector defaults to zero.
  • Otherwise direction and up need to be vectors in a 90 degree angle to each other.

Further helpers

There are more helper functions involving vectors, but they are listed elsewhere because they only work on specific sorts of vectors or involve things that are not vectors.

For example:

• core.hash_node_position (Only works on node positions.)
• core.dir_to_wallmounted (Involves wallmounted param2 values.)

Helper functions

• dump2(obj, name, dumped): returns a string which makes obj human-readable, handles reference loops.
  • obj: arbitrary variable
  • name: string, default: "_"
  • dumped: table, default: {}
• dump(obj, dumped): returns a string which makes obj human-readable
  • obj: arbitrary variable
  • dumped: table, default: {}
• math.hypot(x, y)
  • Get the hypotenuse of a triangle with legs x and y. Useful for distance calculation.
• math.sign(x, tolerance): returns -1, 0 or 1
  • Get the sign of a number.
  • tolerance: number, default: 0.0
  • If the absolute value of x is within the tolerance or x is NaN, 0 is returned.
• math.factorial(x): returns the factorial of x
• math.round(x): Returns x rounded to the nearest integer.
  • At a multiple of 0.5, rounds away from zero.
• string.split(str, separator, include_empty, max_splits, sep_is_pattern)
  • separator: string, cannot be empty, default: ","
  • include_empty: boolean, default: false
  • max_splits: number, if it's negative, splits aren't limited, default: -1
  • sep_is_pattern: boolean, it specifies whether separator is a plain string or a pattern (regex), default: false
  • e.g. "a,b":split"," returns {"a","b"}
• string:trim(): returns the string without whitespace pre- and suffixes
  • e.g. "\n \t\tfoo bar\t ":trim() returns "foo bar"
• core.wrap_text(str, limit, as_table): returns a string or table
  • Adds newlines to the string to keep it within the specified character limit
  • Note that the returned lines may be longer than the limit since it only splits at word borders.
  • limit: number, maximal amount of characters in one line
  • as_table: boolean, if set to true, a table of lines instead of a string is returned, default: false
• core.pos_to_string(pos, decimal_places): returns string "(X,Y,Z)"
  • pos: table {x=X, y=Y, z=Z}
  • Converts the position pos to a human-readable, printable string
  • decimal_places: number, if specified, the x, y and z values of the position are rounded to the given decimal place.
• core.string_to_pos(string): returns a position or nil
  • Same but in reverse.
  • If the string can't be parsed to a position, nothing is returned.
• core.string_to_area("(X1, Y1, Z1) (X2, Y2, Z2)", relative_to):
  • returns two positions
  • Converts a string representing an area box into two positions
  • X1, Y1, ... Z2 are coordinates
  • relative_to: Optional. If set to a position, each coordinate can use the tilde notation for relative positions
  • Tilde notation
    • "~": Relative coordinate
    • "~<number>": Relative coordinate plus <number>
  • Example: core.string_to_area("(1,2,3) (~5,~-5,~)", {x=10,y=10,z=10}) returns {x=1,y=2,z=3}, {x=15,y=5,z=10}
• core.formspec_escape(string): returns a string
  • escapes the characters "[", "]", "\", "," and ";", which cannot be used in formspecs.
• core.is_yes(arg)
  • returns true if passed 'y', 'yes', 'true' or a number that isn't zero.
• core.is_nan(arg)
  • returns true when the passed number represents NaN.
• core.get_us_time()
  • returns time with microsecond precision. May not return wall time.
• table.copy(table): returns a table
  • returns a deep copy of table
• table.indexof(list, val): returns the smallest numerical index containing the value val in the table list. Non-numerical indices are ignored. If val could not be found, -1 is returned. list must not have negative indices.
• table.keyof(table, val): returns the key containing the value val in the table table. If multiple keys contain val, it is unspecified which key will be returned. If val could not be found, nil is returned.
• table.insert_all(table, other_table):
  • Appends all values in other_table to table - uses #table + 1 to find new indices.
• table.key_value_swap(t): returns a table with keys and values swapped
  • If multiple keys in t map to the same value, it is unspecified which value maps to that key.
• table.shuffle(table, [from], [to], [random_func]):
  • Shuffles elements from to to in table in place
  • from defaults to 1
  • to defaults to #table
  • random_func defaults to math.random. This function receives two integers as arguments and should return a random integer inclusively between them.
• core.pointed_thing_to_face_pos(placer, pointed_thing): returns a position.
  • returns the exact position on the surface of a pointed node
• core.get_tool_wear_after_use(uses [, initial_wear])
  • Simulates a tool being used once and returns the added wear, such that, if only this function is used to calculate wear, the tool will break exactly after uses times of uses
  • uses: Number of times the tool can be used
  • initial_wear: The initial wear the tool starts with (default: 0)
• core.get_dig_params(groups, tool_capabilities [, wear]): Simulates an item that digs a node. Returns a table with the following fields:
  • diggable: true if node can be dug, false otherwise.
  • time: Time it would take to dig the node.
  • wear: How much wear would be added to the tool (ignored for non-tools). time and wear are meaningless if node's not diggable Parameters:
  • groups: Table of the node groups of the node that would be dug
  • tool_capabilities: Tool capabilities table of the item
  • wear: Amount of wear the tool starts with (default: 0)
• core.get_hit_params(groups, tool_capabilities [, time_from_last_punch [, wear]]): Simulates an item that punches an object. Returns a table with the following fields:
  • hp: How much damage the punch would cause (between -65535 and 65535).
  • wear: How much wear would be added to the tool (ignored for non-tools). Parameters:
  • groups: Damage groups of the object
  • tool_capabilities: Tool capabilities table of the item
  • time_from_last_punch: time in seconds since last punch action
  • wear: Amount of wear the item starts with (default: 0)

Translations

Texts can be translated client-side with the help of core.translate and translation files.

Translating a string

Two functions are provided to translate strings: core.translate and core.get_translator.

• core.get_translator(textdomain) is a simple wrapper around core.translate and core.translate_n. After local S, NS = core.get_translator(textdomain), we have S(str, ...) equivalent to core.translate(textdomain, str, ...), and NS(str, str_plural, n, ...) to core.translate_n(textdomain, str, str_plural, n, ...). It is intended to be used in the following way, so that it avoids verbose repetitions of core.translate:

  local S, NS = core.get_translator(textdomain)
  S(str, ...)

As an extra commodity, if textdomain is nil, it is assumed to be "" instead.

• core.translate(textdomain, str, ...) translates the string str with the given textdomain for disambiguation. The textdomain must match the textdomain specified in the translation file in order to get the string translated. This can be used so that a string is translated differently in different contexts. It is advised to use the name of the mod as textdomain whenever possible, to avoid clashes with other mods. This function must be given a number of arguments equal to the number of arguments the translated string expects. Arguments are literal strings -- they will not be translated.

• core.translate_n(textdomain, str, str_plural, n, ...) translates the string str with the given textdomain for disambiguaion. The value of n, which must be a nonnegative integer, is used to decide whether to use the singular or the plural version of the string. Depending on the locale of the client, the choice between singular and plural might be more complicated, but the choice will be done automatically using the value of n.

You can read https://www.gnu.org/software/gettext/manual/html_node/Plural-forms.html for more details on the differences of plurals between languages.

Also note that plurals are only handled in .po or .mo files, and not in .tr files.

For instance, suppose we want to greet players when they join and provide a command that shows the amount of time since the player joined. We can do the following:

local S, NS = core.get_translator("hello")
core.register_on_joinplayer(function(player)
    local name = player:get_player_name()
    core.chat_send_player(name, S("Hello @1, how are you today?", name))
end)
core.register_chatcommand("playtime", {
    func = function(name)
        local last_login = core.get_auth_handler().get_auth(name).last_login
        local playtime = math.floor((last_login-os.time())/60)
        return true, NS(
            "You have been playing for @1 minute.",
            "You have been playing for @1 minutes.",
            minutes, tostring(minutes))
    end,
})

When someone called "CoolGuy" joins the game with an old client or a client that does not have localization enabled, they will see Hello CoolGuy, how are you today?. If they use the /playtime command, they will see You have been playing for 1 minute or (for example) You have been playing for 4 minutes.

However, if we have for instance a translation file named hello.de.po containing the following:

msgid ""
msgstr ""
"Plural-Forms: nplurals=2; plural=(n != 1);\n"

msgid "Hello @1, how are you today?"
msgstr "Hallo @1, wie geht es dir heute?"

msgid "You have been playing for @1 minute."
msgid_plural "You have been playing for @1 minutes."
msgstr[0] "Du spielst seit @1 Minute."
msgstr[1] "Du spielst seit @1 Minuten."

and CoolGuy has set a German locale, they will see Hallo CoolGuy, wie geht es dir heute? when they join, and the /playtime command will show them Du spielst seit 1 Minute. or (for example) Du spielst seit 4 Minuten.

Creating and updating translation files

As an alternative to writing translation files by hand (as shown in the above example), it is also possible to generate translation files based on the source code.

It is recommended to first generate a translation template. The translation template includes translatable strings that translators can directly work on. After creating the locale directory, a translation template for the above example using the following command:

xgettext -L lua -kS -kNS:1,2 -kcore.translate:1c,2 -kcore.translate_n:1c,2,3 \
  -d hello -o locale/hello.pot *.lua

The above command can also be used to update the translation template when new translatable strings are added.

The German translator can then create the translation file with

msginit -l de -i locale/hello.pot -o locale/hello.de.po

and provide the translations by editing locale/hello.de.po.

The translation file can be updated using

msgmerge -U locale/hello.de.po locale/hello.pot

Refer to the Gettext manual for further information on creating and updating translation files.

Operations on translated strings

The output of core.translate is a string, with escape sequences adding additional information to that string so that it can be translated on the different clients. In particular, you can't expect operations like string.length to work on them like you would expect them to, or string.gsub to work in the expected manner. However, string concatenation will still work as expected (note that you should only use this for things like formspecs; do not translate sentences by breaking them into parts; arguments should be used instead), and operations such as core.colorize which are also concatenation.

Old translation file format

A translation file has the suffix .[lang].tr, where [lang] is the language it corresponds to. It must be put into the locale subdirectory of the mod. The file should be a text file, with the following format:

• Lines beginning with # textdomain: (the space is significant) can be used to specify the text domain of all following translations in the file.
• All other empty lines or lines beginning with # are ignored.
• Other lines should be in the format original=translated. Both original and translated can contain escape sequences beginning with @ to insert arguments, literal @, = or newline (See [Escapes] below). There must be no extraneous whitespace around the = or at the beginning or the end of the line.

Using the earlier example of greeting the player, the translation file would be

# textdomain: hello
Hello @1, how are you today?=Hallo @1, wie geht es dir heute?

For old translation files, consider using the script mod_translation_updater.py in the Luanti modtools repository to generate and update translation files automatically from the Lua sources.

Gettext translation file format

Gettext files can also be used as translations. A translation file has the suffix .[lang].po or .[lang].mo, depending on whether it is compiled or not, and must also be placed in the locale subdirectory of the mod. The value of textdomain is msgctxt in the gettext files. If msgctxt is not provided, the name of the translation file is used instead.

A typical entry in a .po file would look like:

msgctxt "textdomain"
msgid "Hello world!"
msgstr "Bonjour le monde!"

Escapes

Strings that need to be translated can contain several escapes, preceded by @.

• @@ acts as a literal @.
• @n, where n is a digit between 1 and 9, is an argument for the translated string that will be inlined when translated. Due to how translations are implemented, the original translation string must have its arguments in increasing order, without gaps or repetitions, starting from 1.
• @= acts as a literal =. It is not required in strings given to core.translate, but is in translation files to avoid being confused with the = separating the original from the translation.
• @\n (where the \n is a literal newline) acts as a literal newline. As with @=, this escape is not required in strings given to core.translate, but is in translation files.
• @n acts as a literal newline as well.

Server side translations

On some specific cases, server translation could be useful. For example, filter a list on labels and send results to client. A method is supplied to achieve that:

core.get_translated_string(lang_code, string): resolves translations in the given string just like the client would, using the translation files for lang_code. For this to have any effect, the string needs to contain translation markup, e.g. core.get_translated_string("fr", S("Hello")).

The lang_code to use for a given player can be retrieved from the table returned by core.get_player_information(name).

IMPORTANT: This functionality should only be used for sorting, filtering or similar purposes. You do not need to use this to get translated strings to show up on the client.

Translating content meta

You can translate content meta, such as title and description, by placing translations in a locale/DOMAIN.LANG.tr file. The textdomain defaults to the content name, but can be customised using textdomain in the content's .conf.

Mods and Texture Packs

Say you have a mod called mymod with a short description in mod.conf:

description = This is the short description

Luanti will look for translations in the mymod textdomain as there's no textdomain specified in mod.conf. For example, mymod/locale/mymod.fr.tr:

# textdomain:mymod
This is the short description=Voici la description succincte

Games and Modpacks

For games and modpacks, Luanti will look for the textdomain in all mods.

Say you have a game called mygame with the following game.conf:

description = This is the game's short description
textdomain = mygame

Luanti will then look for the textdomain mygame in all mods, for example, mygame/mods/anymod/locale/mygame.fr.tr. Note that it is still recommended that your textdomain match the mod name, but this isn't required.

Perlin noise

Perlin noise creates a continuously-varying value depending on the input values. Usually in Luanti the input values are either 2D or 3D coordinates in nodes. The result is used during map generation to create the terrain shape, vary heat and humidity to distribute biomes, vary the density of decorations or vary the structure of ores.

Structure of perlin noise

An 'octave' is a simple noise generator that outputs a value between -1 and 1. The smooth wavy noise it generates has a single characteristic scale, almost like a 'wavelength', so on its own does not create fine detail. Due to this perlin noise combines several octaves to create variation on multiple scales. Each additional octave has a smaller 'wavelength' than the previous.

This combination results in noise varying very roughly between -2.0 and 2.0 and with an average value of 0.0, so scale and offset are then used to multiply and offset the noise variation.

The final perlin noise variation is created as follows:

noise = offset + scale * (octave1 +

                      octave2 * persistence +
                      octave3 * persistence ^ 2 +
                      octave4 * persistence ^ 3 +
                      ...)

Noise Parameters

Noise Parameters are commonly called NoiseParams.

offset

After the multiplication by scale this is added to the result and is the final step in creating the noise value. Can be positive or negative.

scale

Once all octaves have been combined, the result is multiplied by this. Can be positive or negative.

spread

For octave1, this is roughly the change of input value needed for a very large variation in the noise value generated by octave1. It is almost like a 'wavelength' for the wavy noise variation. Each additional octave has a 'wavelength' that is smaller than the previous octave, to create finer detail. spread will therefore roughly be the typical size of the largest structures in the final noise variation.

spread is a vector with values for x, y, z to allow the noise variation to be stretched or compressed in the desired axes. Values are positive numbers.

seed

This is a whole number that determines the entire pattern of the noise variation. Altering it enables different noise patterns to be created. With other parameters equal, different seeds produce different noise patterns and identical seeds produce identical noise patterns.

For this parameter you can randomly choose any whole number. Usually it is preferable for this to be different from other seeds, but sometimes it is useful to be able to create identical noise patterns.

In some noise APIs the world seed is added to the seed specified in noise parameters. This is done to make the resulting noise pattern vary in different worlds, and be 'world-specific'.

octaves

The number of simple noise generators that are combined. A whole number, 1 or more. Each additional octave adds finer detail to the noise but also increases the noise calculation load. 3 is a typical minimum for a high quality, complex and natural-looking noise variation. 1 octave has a slight 'gridlike' appearance.

Choose the number of octaves according to the spread and lacunarity, and the size of the finest detail you require. For example: if spread is 512 nodes, lacunarity is 2.0 and finest detail required is 16 nodes, octaves will be 6 because the 'wavelengths' of the octaves will be 512, 256, 128, 64, 32, 16 nodes. Warning: If the 'wavelength' of any octave falls below 1 an error will occur.

persistence

Each additional octave has an amplitude that is the amplitude of the previous octave multiplied by persistence, to reduce the amplitude of finer details, as is often helpful and natural to do so. Since this controls the balance of fine detail to large-scale detail persistence can be thought of as the 'roughness' of the noise.

A positive or negative non-zero number, often between 0.3 and 1.0. A common medium value is 0.5, such that each octave has half the amplitude of the previous octave. This may need to be tuned when altering lacunarity; when doing so consider that a common medium value is 1 / lacunarity.

Instead of persistence, the key persist may be used to the same effect.

lacunarity

Each additional octave has a 'wavelength' that is the 'wavelength' of the previous octave multiplied by 1 / lacunarity, to create finer detail. 'lacunarity' is often 2.0 so 'wavelength' often halves per octave.

A positive number no smaller than 1.0. Values below 2.0 create higher quality noise at the expense of requiring more octaves to cover a particular range of 'wavelengths'.

flags

Leave this field unset for no special handling. Currently supported are defaults, eased and absvalue:

defaults

Specify this if you would like to keep auto-selection of eased/not-eased while specifying some other flags.

eased

Maps noise gradient values onto a quintic S-curve before performing interpolation. This results in smooth, rolling noise. Disable this (noeased) for sharp-looking noise with a slightly gridded appearance. If no flags are specified (or defaults is), 2D noise is eased and 3D noise is not eased. Easing a 3D noise significantly increases the noise calculation load, so use with restraint.

absvalue

The absolute value of each octave's noise variation is used when combining the octaves. The final perlin noise variation is created as follows:

noise = offset + scale * (abs(octave1) +

                      abs(octave2) * persistence +
                      abs(octave3) * persistence ^ 2 +
                      abs(octave4) * persistence ^ 3 +
                      ...)

Format example

For 2D or 3D perlin noise or perlin noise maps:

np_terrain = {
    offset = 0,
    scale = 1,
    spread = {x = 500, y = 500, z = 500},
    seed = 571347,
    octaves = 5,
    persistence = 0.63,
    lacunarity = 2.0,
    flags = "defaults, absvalue",
}

For 2D noise the Z component of spread is still defined but is ignored. A single noise parameter table can be used for 2D or 3D noise.

Ores

Ore types

These tell in what manner the ore is generated.

All default ores are of the uniformly-distributed scatter type.

scatter

Randomly chooses a location and generates a cluster of ore.

If noise_params is specified, the ore will be placed if the 3D perlin noise at that point is greater than the noise_threshold, giving the ability to create a non-equal distribution of ore.

sheet

Creates a sheet of ore in a blob shape according to the 2D perlin noise described by noise_params and noise_threshold. This is essentially an improved version of the so-called "stratus" ore seen in some unofficial mods.

This sheet consists of vertical columns of uniform randomly distributed height, varying between the inclusive range column_height_min and column_height_max. If column_height_min is not specified, this parameter defaults to 1. If column_height_max is not specified, this parameter defaults to clust_size for reverse compatibility. New code should prefer column_height_max.

The column_midpoint_factor parameter controls the position of the column at which ore emanates from. If 1, columns grow upward. If 0, columns grow downward. If 0.5, columns grow equally starting from each direction. column_midpoint_factor is a decimal number ranging in value from 0 to 1. If this parameter is not specified, the default is 0.5.

The ore parameters clust_scarcity and clust_num_ores are ignored for this ore type.

puff

Creates a sheet of ore in a cloud-like puff shape.

As with the sheet ore type, the size and shape of puffs are described by noise_params and noise_threshold and are placed at random vertical positions within the currently generated chunk.

The vertical top and bottom displacement of each puff are determined by the noise parameters np_puff_top and np_puff_bottom, respectively.

blob

Creates a deformed sphere of ore according to 3d perlin noise described by noise_params. The maximum size of the blob is clust_size, and clust_scarcity has the same meaning as with the scatter type.

vein

Creates veins of ore varying in density by according to the intersection of two instances of 3d perlin noise with different seeds, both described by noise_params.

random_factor varies the influence random chance has on placement of an ore inside the vein, which is 1 by default. Note that modifying this parameter may require adjusting noise_threshold.

The parameters clust_scarcity, clust_num_ores, and clust_size are ignored by this ore type.

This ore type is difficult to control since it is sensitive to small changes. The following is a decent set of parameters to work from:

noise_params = {
    offset  = 0,
    scale   = 3,
    spread  = {x=200, y=200, z=200},
    seed    = 5390,
    octaves = 4,
    persistence = 0.5,
    lacunarity = 2.0,
    flags = "eased",
},
noise_threshold = 1.6

WARNING: Use this ore type very sparingly since it is ~200x more computationally expensive than any other ore.

stratum

Creates a single undulating ore stratum that is continuous across mapchunk borders and horizontally spans the world.

The 2D perlin noise described by noise_params defines the Y coordinate of the stratum midpoint. The 2D perlin noise described by np_stratum_thickness defines the stratum's vertical thickness (in units of nodes). Due to being continuous across mapchunk borders the stratum's vertical thickness is unlimited.

If the noise parameter noise_params is omitted the ore will occur from y_min to y_max in a simple horizontal stratum.

A parameter stratum_thickness can be provided instead of the noise parameter np_stratum_thickness, to create a constant thickness.

Leaving out one or both noise parameters makes the ore generation less intensive, useful when adding multiple strata.

y_min and y_max define the limits of the ore generation and for performance reasons should be set as close together as possible but without clipping the stratum's Y variation.

Each node in the stratum has a 1-in-clust_scarcity chance of being ore, so a solid-ore stratum would require a clust_scarcity of 1.

The parameters clust_num_ores, clust_size, noise_threshold and random_factor are ignored by this ore type.

Ore attributes

See section [Flag Specifier Format].

Currently supported flags: puff_cliffs, puff_additive_composition.

puff_cliffs

If set, puff ore generation will not taper down large differences in displacement when approaching the edge of a puff. This flag has no effect for ore types other than puff.

puff_additive_composition

By default, when noise described by np_puff_top or np_puff_bottom results in a negative displacement, the sub-column at that point is not generated. With this attribute set, puff ore generation will instead generate the absolute difference in noise displacement values. This flag has no effect for ore types other than puff.

Decoration types

The varying types of decorations that can be placed.

simple

Creates a 1 times H times 1 column of a specified node (or a random node from a list, if a decoration list is specified). Can specify a certain node it must spawn next to, such as water or lava, for example. Can also generate a decoration of random height between a specified lower and upper bound. This type of decoration is intended for placement of grass, flowers, cacti, papyri, waterlilies and so on.

schematic

Copies a box of MapNodes from a specified schematic file (or raw description). Can specify a probability of a node randomly appearing when placed. This decoration type is intended to be used for multi-node sized discrete structures, such as trees, cave spikes, rocks, and so on.

lsystem

Generates a L-system tree at the position where the decoration is placed. Uses the same L-system as core.spawn_tree, but is faster than using it manually. The treedef field in the decoration definition is used for the tree definition.

Schematics

Schematic specifier

A schematic specifier identifies a schematic by either a filename to a Luanti Schematic file (.mts) or through raw data supplied through Lua, in the form of a table. This table specifies the following fields:

• The size field is a 3D vector containing the dimensions of the provided schematic. (required field)
• The yslice_prob field is a table of {ypos, prob} slice tables. A slice table sets the probability of a particular horizontal slice of the schematic being placed. (optional field) ypos = 0 for the lowest horizontal slice of a schematic. The default of prob is 255.
• The data field is a flat table of MapNode tables making up the schematic, in the order of [z [y [x]]]. (required field) Each MapNode table contains:
  • name: the name of the map node to place (required)
  • prob (alias param1): the probability of this node being placed (default: 255)
  • param2: the raw param2 value of the node being placed onto the map (default: 0)
  • force_place: boolean representing if the node should forcibly overwrite any previous contents (default: false)

About probability values:

• A probability value of 0 or 1 means that node will never appear (0% chance).
• A probability value of 254 or 255 means the node will always appear (100% chance).
• If the probability value p is greater than 1, then there is a (p / 256 * 100) percent chance that node will appear when the schematic is placed on the map.

Schematic attributes

See section [Flag Specifier Format].

Currently supported flags: place_center_x, place_center_y, place_center_z,

                       `force_placement`.

• place_center_x: Placement of this decoration is centered along the X axis.
• place_center_y: Placement of this decoration is centered along the Y axis.
• place_center_z: Placement of this decoration is centered along the Z axis.
• force_placement: Schematic nodes other than "ignore" will replace existing nodes.

Lua Voxel Manipulator

About VoxelManip

VoxelManip is a scripting interface to the internal 'Map Voxel Manipulator' facility. The purpose of this object is for fast, low-level, bulk access to reading and writing Map content. As such, setting map nodes through VoxelManip will lack many of the higher level features and concepts you may be used to with other methods of setting nodes. For example, nodes will not have their construction and destruction callbacks run, and no rollback information is logged.

It is important to note that VoxelManip is designed for speed, and not ease of use or flexibility. If your mod requires a map manipulation facility that will handle 100% of all edge cases, or the use of high level node placement features, perhaps core.set_node() is better suited for the job.

In addition, VoxelManip might not be faster, or could even be slower, for your specific use case. VoxelManip is most effective when setting large areas of map at once - for example, if only setting a 3x3x3 node area, a core.set_node() loop may be more optimal. Always profile code using both methods of map manipulation to determine which is most appropriate for your usage.

A recent simple test of setting cubic areas showed that core.set_node() is faster than a VoxelManip for a 3x3x3 node cube or smaller.

Using VoxelManip

A VoxelManip object can be created any time using either: VoxelManip([p1, p2]), or core.get_voxel_manip([p1, p2]).

If the optional position parameters are present for either of these routines, the specified region will be pre-loaded into the VoxelManip object on creation. Otherwise, the area of map you wish to manipulate must first be loaded into the VoxelManip object using VoxelManip:read_from_map().

Note that VoxelManip:read_from_map() returns two position vectors. The region formed by these positions indicate the minimum and maximum (respectively) positions of the area actually loaded in the VoxelManip, which may be larger than the area requested. For convenience, the loaded area coordinates can also be queried any time after loading map data with VoxelManip:get_emerged_area().

Now that the VoxelManip object is populated with map data, your mod can fetch a copy of this data using either of two methods. VoxelManip:get_node_at(), which retrieves an individual node in a MapNode formatted table at the position requested is the simplest method to use, but also the slowest.

Nodes in a VoxelManip object may also be read in bulk to a flat array table using:

• VoxelManip:get_data() for node content (in Content ID form, see section [Content IDs]),
• VoxelManip:get_light_data() for node light levels, and
• VoxelManip:get_param2_data() for the node type-dependent "param2" values.

See section [Flat array format] for more details.

It is very important to understand that the tables returned by any of the above three functions represent a snapshot of the VoxelManip's internal state at the time of the call. This copy of the data will not magically update itself if another function modifies the internal VoxelManip state. Any functions that modify a VoxelManip's contents work on the VoxelManip's internal state unless otherwise explicitly stated.

Once the bulk data has been edited to your liking, the internal VoxelManip state can be set using:

• VoxelManip:set_data() for node content (in Content ID form, see section [Content IDs]),
• VoxelManip:set_light_data() for node light levels, and
• VoxelManip:set_param2_data() for the node type-dependent param2 values.

The parameter to each of the above three functions can use any table at all in the same flat array format as produced by get_data() etc. and is not required to be a table retrieved from get_data().

Once the internal VoxelManip state has been modified to your liking, the changes can be committed back to the map by calling VoxelManip:write_to_map()

Flat array format

Let

`Nx = p2.X - p1.X + 1`,
`Ny = p2.Y - p1.Y + 1`, and
`Nz = p2.Z - p1.Z + 1`.

Then, for a loaded region of p1..p2, this array ranges from 1 up to and including the value of the expression Nx * Ny * Nz.

Positions offset from p1 are present in the array with the format of:

[
    (0, 0, 0),   (1, 0, 0),   (2, 0, 0),   ... (Nx, 0, 0),
    (0, 1, 0),   (1, 1, 0),   (2, 1, 0),   ... (Nx, 1, 0),
    ...
    (0, Ny, 0),  (1, Ny, 0),  (2, Ny, 0),  ... (Nx, Ny, 0),
    (0, 0, 1),   (1, 0, 1),   (2, 0, 1),   ... (Nx, 0, 1),
    ...
    (0, Ny, 2),  (1, Ny, 2),  (2, Ny, 2),  ... (Nx, Ny, 2),
    ...
    (0, Ny, Nz), (1, Ny, Nz), (2, Ny, Nz), ... (Nx, Ny, Nz)
]

and the array index for a position p contained completely in p1..p2 is:

(p.Z - p1.Z) * Ny * Nx + (p.Y - p1.Y) * Nx + (p.X - p1.X) + 1

Note that this is the same "flat 3D array" format as PerlinNoiseMap:get3dMap_flat(). VoxelArea objects (see section [VoxelArea]) can be used to simplify calculation of the index for a single point in a flat VoxelManip array.

Content IDs

A Content ID is a unique integer identifier for a specific node type. These IDs are used by VoxelManip in place of the node name string for VoxelManip:get_data() and VoxelManip:set_data(). You can use core.get_content_id() to look up the Content ID for the specified node name, and core.get_name_from_content_id() to look up the node name string for a given Content ID. After registration of a node, its Content ID will remain the same throughout execution of the mod. Note that the node being queried needs to have already been been registered.

The following builtin node types have their Content IDs defined as constants:

• core.CONTENT_UNKNOWN: ID for "unknown" nodes
• core.CONTENT_AIR: ID for "air" nodes
• core.CONTENT_IGNORE: ID for "ignore" nodes

Mapgen VoxelManip objects

Inside of on_generated() callbacks, it is possible to retrieve the same VoxelManip object used by the core's Map Generator (commonly abbreviated Mapgen). Most of the rules previously described still apply but with a few differences:

• The Mapgen VoxelManip object is retrieved using: core.get_mapgen_object("voxelmanip")

• This VoxelManip object already has the region of map just generated loaded into it; it's not necessary to call VoxelManip:read_from_map(). Note that the region of map it has loaded is NOT THE SAME as the minp, maxp parameters of on_generated(). Refer to core.get_mapgen_object docs. Once you're done you still need to call VoxelManip:write_to_map()

• The on_generated() callbacks of some mods may place individual nodes in the generated area using non-VoxelManip map modification methods. Because the same Mapgen VoxelManip object is passed through each on_generated() callback, it becomes necessary for the Mapgen VoxelManip object to maintain consistency with the current map state. For this reason, calling any of core.add_node(), core.set_node() or core.swap_node() will also update the Mapgen VoxelManip object's internal state active on the current thread.

• After modifying the Mapgen VoxelManip object's internal buffer, it may be necessary to update lighting information using either: VoxelManip:calc_lighting() or VoxelManip:set_lighting().

Other API functions operating on a VoxelManip

If any VoxelManip contents were set to a liquid node (liquidtype ~= "none"), VoxelManip:update_liquids() must be called for these liquid nodes to begin flowing. It is recommended to call this function only after having written all buffered data back to the VoxelManip object, save for special situations where the modder desires to only have certain liquid nodes begin flowing.

The functions core.generate_ores() and core.generate_decorations() will generate all registered decorations and ores throughout the full area inside of the specified VoxelManip object.

core.place_schematic_on_vmanip() is otherwise identical to core.place_schematic(), except instead of placing the specified schematic directly on the map at the specified position, it will place the schematic inside the VoxelManip.

Notes

• Attempting to read data from a VoxelManip object before map is read will result in a zero-length array table for VoxelManip:get_data(), and an "ignore" node at any position for VoxelManip:get_node_at().

• If you attempt to use a VoxelManip to read a region of the map that has already been generated, but is not currently loaded, that region will be loaded from disk. This means that reading a region of the map with a VoxelManip has a similar effect as calling core.load_area on that region.

• If a region of the map has either not yet been generated or is outside the map boundaries, it is filled with "ignore" nodes. Writing to regions of the map that are not yet generated may result in unexpected behavior. You can use core.emerge_area to make sure that the area you want to read/write is already generated.

• Other mods, or the core itself, could possibly modify the area of the map currently loaded into a VoxelManip object. With the exception of Mapgen VoxelManips (see above section), the internal buffers are not updated. For this reason, it is strongly encouraged to complete the usage of a particular VoxelManip object in the same callback it had been created.

• If a VoxelManip object will be used often, such as in an on_generated() callback, consider passing a file-scoped table as the optional parameter to VoxelManip:get_data(), which serves as a static buffer the function can use to write map data to instead of returning a new table each call. This greatly enhances performance by avoiding unnecessary memory allocations.

Methods

• read_from_map(p1, p2): Loads a chunk of map into the VoxelManip object containing the region formed by p1 and p2.
  • returns actual emerged pmin, actual emerged pmax
• write_to_map([light]): Writes the data loaded from the VoxelManip back to the map.
  • important: data must be set using VoxelManip:set_data() before calling this.
  • if light is true, then lighting is automatically recalculated. The default value is true. If light is false, no light calculations happen, and you should correct all modified blocks with core.fix_light() as soon as possible. Keep in mind that modifying the map where light is incorrect can cause more lighting bugs.
• get_node_at(pos): Returns a MapNode table of the node currently loaded in the VoxelManip at that position
• set_node_at(pos, node): Sets a specific MapNode in the VoxelManip at that position.
• get_data([buffer]): Retrieves the node content data loaded into the VoxelManip object.
  • returns raw node data in the form of an array of node content IDs
  • if the param buffer is present, this table will be used to store the result instead.
• set_data(data): Sets the data contents of the VoxelManip object
• update_map(): Does nothing, kept for compatibility.
• set_lighting(light, [p1, p2]): Set the lighting within the VoxelManip to a uniform value.
  • light is a table, {day=<0...15>, night=<0...15>}
  • To be used only by a VoxelManip object from core.get_mapgen_object.
  • (p1, p2) is the area in which lighting is set, defaults to the whole area if left out.
• get_light_data([buffer]): Gets the light data read into the VoxelManip object
  • Returns an array (indices 1 to volume) of integers ranging from 0 to 255.
  • Each value is the bitwise combination of day and night light values (0 to 15 each).
  • light = day + (night * 16)
  • If the param buffer is present, this table will be used to store the result instead.
• set_light_data(light_data): Sets the param1 (light) contents of each node in the VoxelManip.
  • expects lighting data in the same format that get_light_data() returns
• get_param2_data([buffer]): Gets the raw param2 data read into the VoxelManip object.
  • Returns an array (indices 1 to volume) of integers ranging from 0 to 255.
  • If the param buffer is present, this table will be used to store the result instead.
• set_param2_data(param2_data): Sets the param2 contents of each node in the VoxelManip.
• calc_lighting([p1, p2], [propagate_shadow]): Calculate lighting within the VoxelManip.
  • To be used only with a VoxelManip object from core.get_mapgen_object.
  • (p1, p2) is the area in which lighting is set, defaults to the whole area if left out or nil. For almost all uses these should be left out or nil to use the default.
  • propagate_shadow is an optional boolean deciding whether shadows in a generated mapchunk above are propagated down into the mapchunk, defaults to true if left out.
• update_liquids(): Update liquid flow
• was_modified(): Returns true if the data in the voxel manipulator has been modified since it was last read from the map. This means you have to call get_data again. This only applies to a VoxelManip object from core.get_mapgen_object, where the engine will keep the map and the VM in sync automatically.
  • Note: this doesn't do what you think it does and is subject to removal. Don't use it!
• get_emerged_area(): Returns actual emerged minimum and maximum positions.

VoxelArea

A helper class for voxel areas. It can be created via VoxelArea(pmin, pmax) or VoxelArea:new({MinEdge = pmin, MaxEdge = pmax}). The coordinates are inclusive, like most other things in Luanti.

Methods

• getExtent(): returns a 3D vector containing the size of the area formed by MinEdge and MaxEdge.
• getVolume(): returns the volume of the area formed by MinEdge and MaxEdge.
• index(x, y, z): returns the index of an absolute position in a flat array starting at 1.
  • x, y and z must be integers to avoid an incorrect index result.
  • The position (x, y, z) is not checked for being inside the area volume, being outside can cause an incorrect index result.
  • Useful for things like VoxelManip, raw Schematic specifiers, PerlinNoiseMap:get2d/3dMap, and so on.
• indexp(p): same functionality as index(x, y, z) but takes a vector.
  • As with index(x, y, z), the components of p must be integers, and p is not checked for being inside the area volume.
• position(i): returns the absolute position vector corresponding to index i.
• contains(x, y, z): check if (x,y,z) is inside area formed by MinEdge and MaxEdge.
• containsp(p): same as above, except takes a vector
• containsi(i): same as above, except takes an index i
• iter(minx, miny, minz, maxx, maxy, maxz): returns an iterator that returns indices.
  • from (minx,miny,minz) to (maxx,maxy,maxz) in the order of [z [y [x]]].
• iterp(minp, maxp): same as above, except takes a vector

Y stride and z stride of a flat array

For a particular position in a voxel area, whose flat array index is known, it is often useful to know the index of a neighboring or nearby position. The table below shows the changes of index required for 1 node movements along the axes in a voxel area:

Movement    Change of index
+x          +1
-x          -1
+y          +ystride
-y          -ystride
+z          +zstride
-z          -zstride

If, for example:

local area = VoxelArea(emin, emax)

The values of ystride and zstride can be obtained using area.ystride and area.zstride.

Mapgen objects

A mapgen object is a construct used in map generation. Mapgen objects can be used by an on_generated callback to speed up operations by avoiding unnecessary recalculations, these can be retrieved using the core.get_mapgen_object() function. If the requested Mapgen object is unavailable, or get_mapgen_object() was called outside of an on_generated callback, nil is returned.

The following Mapgen objects are currently available:

voxelmanip

This returns three values; the VoxelManip object to be used, minimum and maximum emerged position, in that order. All mapgens support this object.

heightmap

Returns an array containing the y coordinates of the ground levels of nodes in the most recently generated chunk by the current mapgen.

biomemap

Returns an array containing the biome IDs of nodes in the most recently generated chunk by the current mapgen.

heatmap

Returns an array containing the temperature values of nodes in the most recently generated chunk by the current mapgen.

humiditymap

Returns an array containing the humidity values of nodes in the most recently generated chunk by the current mapgen.

gennotify

Returns a table. You need to announce your interest in a specific field by calling core.set_gen_notify() before map generation happens.

• key = string: generation notification type
• value = list of positions (usually)
  • Exceptions are denoted in the listing below.

Available generation notification types:

• dungeon: bottom center position of dungeon rooms
• temple: as above but for desert temples (mgv6 only)
• cave_begin
• cave_end
• large_cave_begin
• large_cave_end
• custom: data originating from Mapgen environment
  • This is a table.
  • key = user-defined ID (string)
  • value = arbitrary Lua value
• decoration#id: decorations
  • (see below)

Decorations have a key in the format of "decoration#id", where id is the numeric unique decoration ID as returned by core.get_decoration_id(). For example, decoration#123.

The returned positions are the ground surface 'place_on' nodes, not the decorations themselves. A 'simple' type decoration is often 1 node above the returned position and possibly displaced by 'place_offset_y'.

Registered entities

Functions receive a "luaentity" table as self:

• It has the member name, which is the registered name ("mod:thing")
• It has the member object, which is an ObjectRef pointing to the object
• The original prototype is visible directly via a metatable

Callbacks:

• on_activate(self, staticdata, dtime_s)
  • Called when the object is instantiated.
  • dtime_s is the time passed since the object was unloaded, which can be used for updating the entity state.
• on_deactivate(self, removal)
  • Called when the object is about to get removed or unloaded.
  • removal: boolean indicating whether the object is about to get removed. Calling object:remove() on an active object will call this with removal=true. The mapblock the entity resides in being unloaded will call this with removal=false.
  • Note that this won't be called if the object hasn't been activated in the first place. In particular, core.clear_objects({mode = "full"}) won't call this, whereas core.clear_objects({mode = "quick"}) might call this.
• on_step(self, dtime, moveresult)
  • Called on every server tick, after movement and collision processing.
  • dtime: elapsed time since last call
  • moveresult: table with collision info (only available if physical=true)
• on_punch(self, puncher, time_from_last_punch, tool_capabilities, dir, damage)
  • Called when somebody punches the object.
  • Note that you probably want to handle most punches using the automatic armor group system.
  • puncher: an ObjectRef (can be nil)
  • time_from_last_punch: Meant for disallowing spamming of clicks (can be nil).
  • tool_capabilities: capability table of used item (can be nil)
  • dir: unit vector of direction of punch. Always defined. Points from the puncher to the punched.
  • damage: damage that will be done to entity.
  • Can return true to prevent the default damage mechanism.
• on_death(self, killer)
  • Called when the object dies.
  • killer: an ObjectRef (can be nil)
• on_rightclick(self, clicker)
  • Called when clicker pressed the 'place/use' key while pointing to the object (not necessarily an actual rightclick)
  • clicker: an ObjectRef (may or may not be a player)
• on_attach_child(self, child)
  • Called after another object is attached to this object.
  • child: an ObjectRef of the child
• on_detach_child(self, child)
  • Called after another object has detached from this object.
  • child: an ObjectRef of the child
• on_detach(self, parent)
  • Called after detaching from another object.
  • parent: an ObjectRef from where it got detached
  • Note: this is also called before removal from the world.
• get_staticdata(self)
  • Should return a string that will be passed to on_activate when the object is instantiated the next time.

Collision info passed to on_step (moveresult argument):

{
    touching_ground = boolean,
    -- Note that touching_ground is only true if the entity was moving and
    -- collided with ground.

    collides = boolean,
    standing_on_object = boolean,

    collisions = {
        {
            type = string, -- "node" or "object",
            axis = string, -- "x", "y" or "z"
            node_pos = vector, -- if type is "node"
            object = ObjectRef, -- if type is "object"
            -- The position of the entity when the collision occurred.
            -- Available since feature "moveresult_new_pos".
            new_pos = vector,
            old_velocity = vector,
            new_velocity = vector,
        },
        ...
    }
    -- `collisions` does not contain data of unloaded mapblock collisions
    -- or when the velocity changes are negligibly small
}

L-system trees

Tree definition

treedef={
    axiom,         --string  initial tree axiom
    rules_a,       --string  rules set A
    rules_b,       --string  rules set B
    rules_c,       --string  rules set C
    rules_d,       --string  rules set D
    trunk,         --string  trunk node name
    leaves,        --string  leaves node name
    leaves2,       --string  secondary leaves node name
    leaves2_chance,--num     chance (0-100) to replace leaves with leaves2
    angle,         --num     angle in deg
    iterations,    --num     max # of iterations, usually 2 -5
    random_level,  --num     factor to lower number of iterations, usually 0 - 3
    trunk_type,    --string  single/double/crossed) type of trunk: 1 node,
                    --        2x2 nodes or 3x3 in cross shape
    thin_branches, --boolean true -> use thin (1 node) branches
    fruit,         --string  fruit node name
    fruit_chance,  --num     chance (0-100) to replace leaves with fruit node
    seed,          --num     random seed, if no seed is provided, the engine will create one.
}

Key for special L-System symbols used in axioms

• G: move forward one unit with the pen up
• F: move forward one unit with the pen down drawing trunks and branches
• f: move forward one unit with the pen down drawing leaves (100% chance)
• T: move forward one unit with the pen down drawing trunks only
• R: move forward one unit with the pen down placing fruit
• A: replace with rules set A
• B: replace with rules set B
• C: replace with rules set C
• D: replace with rules set D
• a: replace with rules set A, chance 90%
• b: replace with rules set B, chance 80%
• c: replace with rules set C, chance 70%
• d: replace with rules set D, chance 60%
• +: yaw the turtle right by angle parameter
• -: yaw the turtle left by angle parameter
• &: pitch the turtle down by angle parameter
• ^: pitch the turtle up by angle parameter
• /: roll the turtle to the right by angle parameter
• *: roll the turtle to the left by angle parameter
• [: save in stack current state info
• ]: recover from stack state info

Example

Spawn a small apple tree:

pos = {x=230,y=20,z=4}
apple_tree={
    axiom="FFFFFAFFBF",
    rules_a="[&&&FFFFF&&FFFF][&&&++++FFFFF&&FFFF][&&&----FFFFF&&FFFF]",
    rules_b="[&&&++FFFFF&&FFFF][&&&--FFFFF&&FFFF][&&&------FFFFF&&FFFF]",
    trunk="default:tree",
    leaves="default:leaves",
    angle=30,
    iterations=2,
    random_level=0,
    trunk_type="single",
    thin_branches=true,
    fruit_chance=10,
    fruit="default:apple"
}
core.spawn_tree(pos,apple_tree)

Privileges

Privileges provide a means for server administrators to give certain players access to special abilities in the engine, games or mods. For example, game moderators may need to travel instantly to any place in the world, this ability is implemented in /teleport command which requires teleport privilege.

Registering privileges

A mod can register a custom privilege using core.register_privilege function to give server administrators fine-grained access control over mod functionality.

For consistency and practical reasons, privileges should strictly increase the abilities of the user. Do not register custom privileges that e.g. restrict the player from certain in-game actions.

Checking privileges

A mod can call core.check_player_privs to test whether a player has privileges to perform an operation. Also, when registering a chat command with core.register_chatcommand a mod can declare privileges that the command requires using the privs field of the command definition.

Managing player privileges

A mod can update player privileges using core.set_player_privs function. Players holding the privs privilege can see and manage privileges for all players on the server.

A mod can subscribe to changes in player privileges using core.register_on_priv_grant and core.register_on_priv_revoke functions.

Built-in privileges

Luanti includes a set of built-in privileges that control capabilities provided by the Luanti engine and can be used by mods:

• Basic privileges are normally granted to all players:

  • shout: can communicate using the in-game chat.
  • interact: can modify the world by digging, building and interacting with the nodes, entities and other players. Players without the interact privilege can only travel and observe the world.

• Advanced privileges allow bypassing certain aspects of the gameplay:

  • fast: can use "fast mode" to move with maximum speed.
  • fly: can use "fly mode" to move freely above the ground without falling.
  • noclip: can use "noclip mode" to fly through solid nodes (e.g. walls).
  • teleport: can use /teleport command to move to any point in the world.
  • creative: can access creative inventory.
  • bring: can teleport other players to oneself.
  • give: can use /give and /giveme commands to give any item in the game to oneself or others.
  • settime: can use /time command to change current in-game time.
  • debug: can enable wireframe rendering mode.

• Security-related privileges:

  • privs: can modify privileges of the players using /grant[me] and /revoke[me] commands.
  • basic_privs: can grant and revoke basic privileges as defined by the basic_privs setting.
  • kick: can kick other players from the server using /kick command.
  • ban: can ban other players using /ban command.
  • password: can use /setpassword and /clearpassword commands to manage players' passwords.
  • protection_bypass: can bypass node protection. Note that the engine does not act upon this privilege, it is only an implementation suggestion for games.

• Administrative privileges:

  • server: can use /fixlight, /deleteblocks and /deleteobjects commands. Can clear inventory of other players using /clearinv command.
  • rollback: can use /rollback_check and /rollback commands.

Related settings

Luanti includes the following settings to control behavior of privileges:

• default_privs: defines privileges granted to new players.
• basic_privs: defines privileges that can be granted/revoked by players having the basic_privs privilege. This can be used, for example, to give limited moderation powers to selected users.

'core' namespace reference

Utilities

• core.get_current_modname(): returns the currently loading mod's name, when loading a mod.
• core.get_modpath(modname): returns the directory path for a mod, e.g. "/home/user/.minetest/usermods/modname".
  • Returns nil if the mod is not enabled or does not exist (not installed).
  • Works regardless of whether the mod has been loaded yet.
  • Useful for loading additional .lua modules or static data from a mod, or checking if a mod is enabled.
• core.get_modnames(): returns a list of enabled mods, sorted alphabetically.
  • Does not include disabled mods, even if they are installed.
• core.get_game_info(): returns a table containing information about the current game. Note that other meta information (e.g. version/release number) can be manually read from game.conf in the game's root directory.

  {
      id = string,
      title = string,
      author = string,
      -- The root directory of the game
      path = string,
  }

• core.get_worldpath(): returns e.g. "/home/user/.minetest/world"
  • Useful for storing custom data
• core.get_mod_data_path(): returns e.g. "/home/user/.minetest/mod_data/mymod"
  • Useful for storing custom data independently of worlds.
  • Must be called during mod load time.
  • Can read or write to this directory at any time.
  • It's possible that multiple Luanti instances are running at the same time, which may lead to corruption if you are not careful.
• core.is_singleplayer()
• core.features: Table containing API feature flags

  {
      glasslike_framed = true,  -- 0.4.7
      nodebox_as_selectionbox = true,  -- 0.4.7
      get_all_craft_recipes_works = true,  -- 0.4.7
      -- The transparency channel of textures can optionally be used on
      -- nodes (0.4.7)
      use_texture_alpha = true,
      -- Tree and grass ABMs are no longer done from C++ (0.4.8)
      no_legacy_abms = true,
      -- Texture grouping is possible using parentheses (0.4.11)
      texture_names_parens = true,
      -- Unique Area ID for AreaStore:insert_area (0.4.14)
      area_store_custom_ids = true,
      -- add_entity supports passing initial staticdata to on_activate
      -- (0.4.16)
      add_entity_with_staticdata = true,
      -- Chat messages are no longer predicted (0.4.16)
      no_chat_message_prediction = true,
      -- The transparency channel of textures can optionally be used on
      -- objects (ie: players and lua entities) (5.0.0)
      object_use_texture_alpha = true,
      -- Object selectionbox is settable independently from collisionbox
      -- (5.0.0)
      object_independent_selectionbox = true,
      -- Specifies whether binary data can be uploaded or downloaded using
      -- the HTTP API (5.1.0)
      httpfetch_binary_data = true,
      -- Whether formspec_version[<version>] may be used (5.1.0)
      formspec_version_element = true,
      -- Whether AreaStore's IDs are kept on save/load (5.1.0)
      area_store_persistent_ids = true,
      -- Whether core.find_path is functional (5.2.0)
      pathfinder_works = true,
      -- Whether Collision info is available to an objects' on_step (5.3.0)
      object_step_has_moveresult = true,
      -- Whether get_velocity() and add_velocity() can be used on players (5.4.0)
      direct_velocity_on_players = true,
      -- nodedef's use_texture_alpha accepts new string modes (5.4.0)
      use_texture_alpha_string_modes = true,
      -- degrotate param2 rotates in units of 1.5° instead of 2°
      -- thus changing the range of values from 0-179 to 0-240 (5.5.0)
      degrotate_240_steps = true,
      -- ABM supports min_y and max_y fields in definition (5.5.0)
      abm_min_max_y = true,
      -- dynamic_add_media supports passing a table with options (5.5.0)
      dynamic_add_media_table = true,
      -- particlespawners support texpools and animation of properties,
      -- particle textures support smooth fade and scale animations, and
      -- sprite-sheet particle animations can by synced to the lifetime
      -- of individual particles (5.6.0)
      particlespawner_tweenable = true,
      -- allows get_sky to return a table instead of separate values (5.6.0)
      get_sky_as_table = true,
      -- VoxelManip:get_light_data accepts an optional buffer argument (5.7.0)
      get_light_data_buffer = true,
      -- When using a mod storage backend that is not "files" or "dummy",
      -- the amount of data in mod storage is not constrained by
      -- the amount of RAM available. (5.7.0)
      mod_storage_on_disk = true,
      -- "zstd" method for compress/decompress (5.7.0)
      compress_zstd = true,
      -- Sound parameter tables support start_time (5.8.0)
      sound_params_start_time = true,
      -- New fields for set_physics_override: speed_climb, speed_crouch,
      -- liquid_fluidity, liquid_fluidity_smooth, liquid_sink,
      -- acceleration_default, acceleration_air (5.8.0)
      physics_overrides_v2 = true,
      -- In HUD definitions the field `type` is used and `hud_elem_type` is deprecated (5.9.0)
      hud_def_type_field = true,
      -- PseudoRandom and PcgRandom state is restorable
      -- PseudoRandom has get_state method
      -- PcgRandom has get_state and set_state methods (5.9.0)
      random_state_restore = true,
      -- core.after guarantees that coexisting jobs are executed primarily
      -- in order of expiry and secondarily in order of registration (5.9.0)
      after_order_expiry_registration = true,
      -- wallmounted nodes mounted at floor or ceiling may additionally
      -- be rotated by 90° with special param2 values (5.9.0)
      wallmounted_rotate = true,
      -- Availability of the `pointabilities` property in the item definition (5.9.0)
      item_specific_pointabilities = true,
      -- Nodes `pointable` property can be `"blocking"` (5.9.0)
      blocking_pointability_type = true,
      -- dynamic_add_media can be called at startup when leaving callback as `nil` (5.9.0)
      dynamic_add_media_startup = true,
      -- dynamic_add_media supports `filename` and `filedata` parameters (5.9.0)
      dynamic_add_media_filepath = true,
       -- L-system decoration type (5.9.0)
      lsystem_decoration_type = true,
      -- Overridable pointing range using the itemstack meta key `"range"` (5.9.0)
      item_meta_range = true,
      -- Allow passing an optional "actor" ObjectRef to the following functions:
      -- core.place_node, core.dig_node, core.punch_node (5.9.0)
      node_interaction_actor = true,
      -- "new_pos" field in entity moveresult (5.9.0)
      moveresult_new_pos = true,
      -- Allow removing definition fields in `core.override_item` (5.9.0)
      override_item_remove_fields = true,
      -- The predefined hotbar is a Lua HUD element of type `hotbar` (5.10.0)
      hotbar_hud_element = true,
      -- Bulk LBM support (5.10.0)
      bulk_lbms = true,
      -- ABM supports field without_neighbors (5.10.0)
      abm_without_neighbors = true,
      -- biomes have a weight parameter (5.11.0)
      biome_weights = true,
      -- Particles can specify a "clip" blend mode (5.11.0)
      particle_blend_clip = true,
  }

• core.has_feature(arg): returns boolean, missing_features
  • arg: string or table in format {foo=true, bar=true}
  • missing_features: {foo=true, bar=true}
• core.get_player_information(player_name): Table containing information about a player. Example return value:

  {
      address = "127.0.0.1",     -- IP address of client
      ip_version = 4,            -- IPv4 / IPv6
      connection_uptime = 200,   -- seconds since client connected
      protocol_version = 32,     -- protocol version used by client
      formspec_version = 2,      -- supported formspec version
      lang_code = "fr",          -- Language code used for translation

      -- the following keys can be missing if no stats have been collected yet
      min_rtt = 0.01,            -- minimum round trip time
      max_rtt = 0.2,             -- maximum round trip time
      avg_rtt = 0.02,            -- average round trip time
      min_jitter = 0.01,         -- minimum packet time jitter
      max_jitter = 0.5,          -- maximum packet time jitter
      avg_jitter = 0.03,         -- average packet time jitter
      -- the following information is available in a debug build only!!!
      -- DO NOT USE IN MODS
      --ser_vers = 26,             -- serialization version used by client
      --major = 0,                 -- major version number
      --minor = 4,                 -- minor version number
      --patch = 10,                -- patch version number
      --vers_string = "0.4.9-git", -- full version string
      --state = "Active"           -- current client state
  }

• core.get_player_window_information(player_name):

  -- Will only be present if the client sent this information (requires v5.7+)
  --
  -- Note that none of these things are constant, they are likely to change during a client
  -- connection as the player resizes the window and moves it between monitors
  --
  -- real_gui_scaling and real_hud_scaling can be used instead of DPI.
  -- OSes don't necessarily give the physical DPI, as they may allow user configuration.
  -- real_*_scaling is just OS DPI / 96 but with another level of user configuration.
  {
      -- Current size of the in-game render target (pixels).
      --
      -- This is usually the window size, but may be smaller in certain situations,
      -- such as side-by-side mode.
      size = {
          x = 1308,
          y = 577,
      },

      -- Estimated maximum formspec size before Luanti will start shrinking the
      -- formspec to fit. For a fullscreen formspec, use this formspec size and
      -- `padding[0,0]`. `bgcolor[;true]` is also recommended.
      max_formspec_size = {
          x = 20,
          y = 11.25
      },

      -- GUI Scaling multiplier
      -- Equal to the setting `gui_scaling` multiplied by `dpi / 96`
      real_gui_scaling = 1,

      -- HUD Scaling multiplier
      -- Equal to the setting `hud_scaling` multiplied by `dpi / 96`
      real_hud_scaling = 1,

      -- Whether the touchscreen controls are enabled.
      -- Usually (but not always) `true` on Android.
      -- Requires at least version 5.9.0 on the client. For older clients, it
      -- is always set to `false`.
      touch_controls = false,
  }

• core.mkdir(path): returns success.
  • Creates a directory specified by path, creating parent directories if they don't exist.
• core.rmdir(path, recursive): returns success.
  • Removes a directory specified by path.
  • If recursive is set to true, the directory is recursively removed. Otherwise, the directory will only be removed if it is empty.
  • Returns true on success, false on failure.
• core.cpdir(source, destination): returns success.
  • Copies a directory specified by path to destination
  • Any files in destination will be overwritten if they already exist.
  • Returns true on success, false on failure.
• core.mvdir(source, destination): returns success.
  • Moves a directory specified by path to destination.
  • If the destination is a non-empty directory, then the move will fail.
  • Returns true on success, false on failure.
• core.get_dir_list(path, [is_dir]): returns list of entry names
  • is_dir is one of:
    • nil: return all entries,
    • true: return only subdirectory names, or
    • false: return only file names.
• core.safe_file_write(path, content): returns boolean indicating success
  • Replaces contents of file at path with new contents in a safe (atomic) way. Use this instead of below code when writing e.g. database files: local f = io.open(path, "wb"); f:write(content); f:close()
• core.get_version(): returns a table containing components of the engine version. Components:
  • project: Name of the project, eg, "Luanti"
  • string: Simple version, eg, "1.2.3-dev"
  • proto_min: The minimum supported protocol version
  • proto_max: The maximum supported protocol version
  • hash: Full git version (only set if available), eg, "1.2.3-dev-01234567-dirty".
  • is_dev: Boolean value indicating whether it's a development build Use this for informational purposes only. The information in the returned table does not represent the capabilities of the engine, nor is it reliable or verifiable. Compatible forks will have a different name and version entirely. To check for the presence of engine features, test whether the functions exported by the wanted features exist. For example: if core.check_for_falling then ... end.
• core.sha1(data, [raw]): returns the sha1 hash of data
  • data: string of data to hash
  • raw: return raw bytes instead of hex digits, default: false
• core.sha256(data, [raw]): returns the sha256 hash of data
  • data: string of data to hash
  • raw: return raw bytes instead of hex digits, default: false
• core.colorspec_to_colorstring(colorspec): Converts a ColorSpec to a ColorString. If the ColorSpec is invalid, returns nil.
  • colorspec: The ColorSpec to convert
• core.colorspec_to_bytes(colorspec): Converts a ColorSpec to a raw string of four bytes in an RGBA layout, returned as a string.
  • colorspec: The ColorSpec to convert
• core.colorspec_to_table(colorspec): Converts a ColorSpec into RGBA table form. If the ColorSpec is invalid, returns nil. You can use this to parse ColorStrings.
  • colorspec: The ColorSpec to convert
• core.time_to_day_night_ratio(time_of_day): Returns a "day-night ratio" value (as accepted by ObjectRef:override_day_night_ratio) that is equivalent to the given "time of day" value (as returned by core.get_timeofday).
• core.encode_png(width, height, data, [compression]): Encode a PNG image and return it in string form.
  • width: Width of the image
  • height: Height of the image
  • data: Image data, one of:
    • array table of ColorSpec, length must be width*height
    • string with raw RGBA pixels, length must be width*height*4
  • compression: Optional zlib compression level, number in range 0 to 9. The data is one-dimensional, starting in the upper left corner of the image and laid out in scanlines going from left to right, then top to bottom. You can use colorspec_to_bytes to generate raw RGBA values. Palettes are not supported at the moment. You may use this to procedurally generate textures during server init.
• core.urlencode(str): Encodes reserved URI characters by a percent sign followed by two hex digits. See RFC 3986, section 2.3.

Logging

• core.debug(...)
  • Equivalent to core.log(table.concat({...}, "\t"))
• core.log([level,] text)
  • level is one of "none", "error", "warning", "action", "info", or "verbose". Default is "none".

Registration functions

Call these functions only at load time!

Environment

• core.register_node(name, node definition)
• core.register_craftitem(name, item definition)
• core.register_tool(name, item definition)
• core.override_item(name, redefinition, del_fields)
  • redefinition is a table of fields [name] = new_value, overwriting fields of or adding fields to the existing definition.
  • del_fields is a list of field names to be set to nil ("deleted from") the original definition.
  • Overrides fields of an item registered with register_node/tool/craftitem.
  • Note: Item must already be defined, (opt)depend on the mod defining it.
  • Example: core.override_item("default:mese", {light_source=core.LIGHT_MAX}, {"sounds"}): Overwrites the light_source field, removes the sounds from the definition of the mese block.
• core.unregister_item(name)
  • Unregisters the item from the engine, and deletes the entry with key name from core.registered_items and from the associated item table according to its nature: core.registered_nodes, etc.
• core.register_entity(name, entity definition)
• core.register_abm(abm definition)
• core.register_lbm(lbm definition)
• core.register_alias(alias, original_name)
  • Also use this to set the 'mapgen aliases' needed in a game for the core mapgens. See [Mapgen aliases] section above.
• core.register_alias_force(alias, original_name)
• core.register_ore(ore definition)
  • Returns an integer object handle uniquely identifying the registered ore on success.
  • The order of ore registrations determines the order of ore generation.
• core.register_biome(biome definition)
  • Returns an integer object handle uniquely identifying the registered biome on success. To get the biome ID, use core.get_biome_id.
• core.unregister_biome(name)
  • Unregisters the biome from the engine, and deletes the entry with key name from core.registered_biomes.
  • Warning: This alters the biome to biome ID correspondences, so any decorations or ores using the 'biomes' field must afterwards be cleared and re-registered.
• core.register_decoration(decoration definition)
  • Returns an integer object handle uniquely identifying the registered decoration on success. To get the decoration ID, use core.get_decoration_id.
  • The order of decoration registrations determines the order of decoration generation.
• core.register_schematic(schematic definition)
  • Returns an integer object handle uniquely identifying the registered schematic on success.
  • If the schematic is loaded from a file, the name field is set to the filename.
  • If the function is called when loading the mod, and name is a relative path, then the current mod path will be prepended to the schematic filename.
• core.clear_registered_biomes()
  • Clears all biomes currently registered.
  • Warning: Clearing and re-registering biomes alters the biome to biome ID correspondences, so any decorations or ores using the 'biomes' field must afterwards be cleared and re-registered.
• core.clear_registered_decorations()
  • Clears all decorations currently registered.
• core.clear_registered_ores()
  • Clears all ores currently registered.
• core.clear_registered_schematics()
  • Clears all schematics currently registered.

Gameplay

• core.register_craft(recipe)
  • Check recipe table syntax for different types below.
• core.clear_craft(recipe)
  • Will erase existing craft based either on output item or on input recipe.
  • Specify either output or input only. If you specify both, input will be ignored. For input use the same recipe table syntax as for core.register_craft(recipe). For output specify only the item, without a quantity.
  • Returns false if no erase candidate could be found, otherwise returns true.
  • Warning! The type field ("shaped", "cooking" or any other) will be ignored if the recipe contains output. Erasing is then done independently from the crafting method.
• core.register_chatcommand(cmd, chatcommand definition)
• core.override_chatcommand(name, redefinition)
  • Overrides fields of a chatcommand registered with register_chatcommand.
• core.unregister_chatcommand(name)
  • Unregisters a chatcommands registered with register_chatcommand.
• core.register_privilege(name, definition)
  • definition can be a description or a definition table (see [Privilege definition]).
  • If it is a description, the priv will be granted to singleplayer and admin by default.
  • To allow players with basic_privs to grant, see the basic_privs minetest.conf setting.
• core.register_authentication_handler(authentication handler definition)
  • Registers an auth handler that overrides the builtin one.
  • This function can be called by a single mod once only.

Global callback registration functions

Call these functions only at load time!

• core.register_globalstep(function(dtime))
  • Called every server step, usually interval of 0.1s.
  • dtime is the time since last execution in seconds.
• core.register_on_mods_loaded(function())
  • Called after mods have finished loading and before the media is cached or the aliases handled.
• core.register_on_shutdown(function())
  • Called before server shutdown
  • Players that were kicked by the shutdown procedure are still fully accessible in core.get_connected_players().
  • Warning: If the server terminates abnormally (i.e. crashes), the registered callbacks will likely not be run. Data should be saved at semi-frequent intervals as well as on server shutdown.
• core.register_on_placenode(function(pos, newnode, placer, oldnode, itemstack, pointed_thing))
  • Called when a node has been placed
  • If return true no item is taken from itemstack
  • placer may be any valid ObjectRef or nil.
  • Not recommended; use on_construct or after_place_node in node definition whenever possible.
• core.register_on_dignode(function(pos, oldnode, digger))
  • Called when a node has been dug.
  • Not recommended; Use on_destruct or after_dig_node in node definition whenever possible.
• core.register_on_punchnode(function(pos, node, puncher, pointed_thing))
  • Called when a node is punched
• core.register_on_generated(function(minp, maxp, blockseed))
  • Called after generating a piece of world between minp and maxp.
  • Avoid using this whenever possible. As with other callbacks this blocks the main thread and introduces noticeable latency. Consider [Mapgen environment] for an alternative.
• core.register_on_newplayer(function(ObjectRef))
  • Called when a new player enters the world for the first time
• core.register_on_punchplayer(function(player, hitter, time_from_last_punch, tool_capabilities, dir, damage))
  • Called when a player is punched
  • Note: This callback is invoked even if the punched player is dead.
  • player: ObjectRef - Player that was punched
  • hitter: ObjectRef - Player that hit. Can be nil.
  • time_from_last_punch: Meant for disallowing spamming of clicks (can be nil).
  • tool_capabilities: Capability table of used item (can be nil)
  • dir: Unit vector of direction of punch. Always defined. Points from the puncher to the punched.
  • damage: Number that represents the damage calculated by the engine
  • should return true to prevent the default damage mechanism
• core.register_on_rightclickplayer(function(player, clicker))
  • Called when the 'place/use' key was used while pointing a player (not necessarily an actual rightclick)
  • player: ObjectRef - Player that is acted upon
  • clicker: ObjectRef - Object that acted upon player, may or may not be a player
• core.register_on_player_hpchange(function(player, hp_change, reason), modifier)
  • Called when the player gets damaged or healed
  • When hp == 0, damage doesn't trigger this callback.
  • When hp == hp_max, healing does still trigger this callback.
  • player: ObjectRef of the player
  • hp_change: the amount of change. Negative when it is damage.
    • Historically, the new HP value was clamped to [0, 65535] before calculating the HP change. This clamping has been removed as of version 5.10.0
  • reason: a PlayerHPChangeReason table.
    • The type field will have one of the following values:
      • set_hp: A mod or the engine called set_hp without giving a type - use this for custom damage types.
      • punch: Was punched. reason.object will hold the puncher, or nil if none.
      • fall
      • node_damage: damage_per_second from a neighboring node. reason.node will hold the node name or nil. reason.node_pos will hold the position of the node
      • drown
      • respawn
    • Any of the above types may have additional fields from mods.
    • reason.from will be mod or engine.
  • modifier: when true, the function should return the actual hp_change. Note: modifiers only get a temporary hp_change that can be modified by later modifiers. Modifiers can return true as a second argument to stop the execution of further functions. Non-modifiers receive the final HP change calculated by the modifiers.
• core.register_on_dieplayer(function(ObjectRef, reason))
  • Called when a player dies
  • reason: a PlayerHPChangeReason table, see register_on_player_hpchange
  • For customizing the death screen, see core.show_death_screen.
• core.register_on_respawnplayer(function(ObjectRef))
  • Called when player is to be respawned
  • Called before repositioning of player occurs
  • return true in func to disable regular player placement
• core.register_on_prejoinplayer(function(name, ip))
  • Called when a client connects to the server, prior to authentication
  • If it returns a string, the client is disconnected with that string as reason.
• core.register_on_joinplayer(function(ObjectRef, last_login))
  • Called when a player joins the game
  • last_login: The timestamp of the previous login, or nil if player is new
• core.register_on_leaveplayer(function(ObjectRef, timed_out))
  • Called when a player leaves the game
  • Does not get executed for connected players on shutdown.
  • timed_out: True for timeout, false for other reasons.
• core.register_on_authplayer(function(name, ip, is_success))
  • Called when a client attempts to log into an account.
  • name: The name of the account being authenticated.
  • ip: The IP address of the client
  • is_success: Whether the client was successfully authenticated
  • For newly registered accounts, is_success will always be true
• core.register_on_auth_fail(function(name, ip))
  • Deprecated: use core.register_on_authplayer(name, ip, is_success) instead.
• core.register_on_cheat(function(ObjectRef, cheat))
  • Called when a player cheats
  • cheat: {type=<cheat_type>}, where <cheat_type> is one of:
    • moved_too_fast
    • interacted_too_far
    • interacted_with_self
    • interacted_while_dead
    • finished_unknown_dig
    • dug_unbreakable
    • dug_too_fast
• core.register_on_chat_message(function(name, message))
  • Called always when a player says something
  • Return true to mark the message as handled, which means that it will not be sent to other players.
• core.register_on_chatcommand(function(name, command, params))
  • Called always when a chatcommand is triggered, before core.registered_chatcommands is checked to see if the command exists, but after the input is parsed.
  • Return true to mark the command as handled, which means that the default handlers will be prevented.
• core.register_on_player_receive_fields(function(player, formname, fields))
  • Called when the server received input from player. Specifically, this is called on any of the following events:
    • a button was pressed,
    • Enter was pressed while the focus was on a text field
    • a checkbox was toggled,
    • something was selected in a dropdown list,
    • a different tab was selected,
    • selection was changed in a textlist or table,
    • an entry was double-clicked in a textlist or table,
    • a scrollbar was moved, or
    • the form was actively closed by the player.
  • formname is the name passed to core.show_formspec. Special case: The empty string refers to the player inventory (the formspec set by the set_inventory_formspec player method).
  • Fields are sent for formspec elements which define a field. fields is a table containing each formspecs element value (as string), with the name parameter as index for each. The value depends on the formspec element type:
    • animated_image: Returns the index of the current frame.
    • button and variants: If pressed, contains the user-facing button text as value. If not pressed, is nil
    • field, textarea and variants: Text in the field
    • dropdown: Either the index or value, depending on the index event dropdown argument.
    • tabheader: Tab index, starting with "1" (only if tab changed)
    • checkbox: "true" if checked, "false" if unchecked
    • textlist: See core.explode_textlist_event
    • table: See core.explode_table_event
    • scrollbar: See core.explode_scrollbar_event
    • Special case: ["quit"]="true" is sent when the user actively closed the form by mouse click, keypress or through a button_exit[] element.
    • Special case: ["key_enter"]="true" is sent when the user pressed the Enter key and the focus was either nowhere (causing the formspec to be closed) or on a button. If the focus was on a text field, additionally, the index key_enter_field contains the name of the text field. See also: field_close_on_enter.
  • Newest functions are called first
  • If function returns true, remaining functions are not called
• core.register_on_craft(function(itemstack, player, old_craft_grid, craft_inv))
  • Called when player crafts something
  • itemstack is the output
  • old_craft_grid contains the recipe (Note: the one in the inventory is cleared).
  • craft_inv is the inventory with the crafting grid
  • Return either an ItemStack, to replace the output, or nil, to not modify it.
• core.register_craft_predict(function(itemstack, player, old_craft_grid, craft_inv))
  • The same as before, except that it is called before the player crafts, to make craft prediction, and it should not change anything.
• core.register_allow_player_inventory_action(function(player, action, inventory, inventory_info))
  • Determines how much of a stack may be taken, put or moved to a player inventory.
  • Function arguments: see core.register_on_player_inventory_action
  • Return a numeric value to limit the amount of items to be taken, put or moved. A value of -1 for take will make the source stack infinite.
• core.register_on_player_inventory_action(function(player, action, inventory, inventory_info))
  • Called after an item take, put or move event from/to/in a player inventory
  • These inventory actions are recognized:
    • move: Item was moved within the player inventory
    • put: Item was put into player inventory from another inventory
    • take: Item was taken from player inventory and put into another inventory
  • player (type ObjectRef) is the player who modified the inventory inventory (type InvRef).
  • List of possible action (string) values and their inventory_info (table) contents:
    • move: {from_list=string, to_list=string, from_index=number, to_index=number, count=number}
    • put: {listname=string, index=number, stack=ItemStack}
    • take: Same as put
  • Does not accept or handle any return value.
• core.register_on_protection_violation(function(pos, name))
  • Called by builtin and mods when a player violates protection at a position (eg, digs a node or punches a protected entity).
  • The registered functions can be called using core.record_protection_violation.
  • The provided function should check that the position is protected by the mod calling this function before it prints a message, if it does, to allow for multiple protection mods.
• core.register_on_item_eat(function(hp_change, replace_with_item, itemstack, user, pointed_thing))
  • Called when an item is eaten, by core.item_eat
  • Return itemstack to cancel the default item eat response (i.e.: hp increase).
• core.register_on_item_pickup(function(itemstack, picker, pointed_thing, time_from_last_punch, ...))
  • Called by core.item_pickup before an item is picked up.
  • Function is added to core.registered_on_item_pickups.
  • Oldest functions are called first.
  • Parameters are the same as in the on_pickup callback.
  • Return an itemstack to cancel the default item pick-up response (i.e.: adding the item into inventory).
• core.register_on_priv_grant(function(name, granter, priv))
  • Called when granter grants the priv priv to name.
  • Note that the callback will be called twice if it's done by a player, once with granter being the player name, and again with granter being nil.
• core.register_on_priv_revoke(function(name, revoker, priv))
  • Called when revoker revokes the priv priv from name.
  • Note that the callback will be called twice if it's done by a player, once with revoker being the player name, and again with revoker being nil.
• core.register_can_bypass_userlimit(function(name, ip))
  • Called when name user connects with ip.
  • Return true to by pass the player limit
• core.register_on_modchannel_message(function(channel_name, sender, message))
  • Called when an incoming mod channel message is received
  • You should have joined some channels to receive events.
  • If message comes from a server mod, sender field is an empty string.
• core.register_on_liquid_transformed(function(pos_list, node_list))
  • Called after liquid nodes (liquidtype ~= "none") are modified by the engine's liquid transformation process.
  • pos_list is an array of all modified positions.
  • node_list is an array of the old node that was previously at the position with the corresponding index in pos_list.
• core.register_on_mapblocks_changed(function(modified_blocks, modified_block_count))
  • Called soon after any nodes or node metadata have been modified. No modifications will be missed, but there may be false positives.
  • Will never be called more than once per server step.
  • modified_blocks is the set of modified mapblock position hashes. These are in the same format as those produced by core.hash_node_position, and can be converted to positions with core.get_position_from_hash. The set is a table where the keys are hashes and the values are true.
  • modified_block_count is the number of entries in the set.
  • Note: callbacks must be registered at mod load time.

Setting-related

• core.settings: Settings object containing all of the settings from the main config file (minetest.conf). See [Settings].
• core.setting_get_pos(name): Loads a setting from the main settings and parses it as a position (in the format (1,2,3)). Returns a position or nil. Deprecated: use core.settings:get_pos() instead

Authentication

• core.string_to_privs(str[, delim]):
  • Converts string representation of privs into table form
  • delim: String separating the privs. Defaults to ",".
  • Returns { priv1 = true, ... }
• core.privs_to_string(privs[, delim]):
  • Returns the string representation of privs
  • delim: String to delimit privs. Defaults to ",".
• core.get_player_privs(name) -> {priv1=true,...}

• core.check_player_privs(player_or_name, ...): returns bool, missing_privs

  • A quickhand for checking privileges.
  • player_or_name: Either a Player object or the name of a player.
  • ... is either a list of strings, e.g. "priva", "privb" or a table, e.g. { priva = true, privb = true }.

• core.check_password_entry(name, entry, password)

  • Returns true if the "password entry" for a player with name matches given password, false otherwise.
  • The "password entry" is the password representation generated by the engine as returned as part of a get_auth() call on the auth handler.
  • Only use this function for making it possible to log in via password from external protocols such as IRC, other uses are frowned upon.

• core.get_password_hash(name, raw_password)

  • Convert a name-password pair to a password hash that Luanti can use.
  • The returned value alone is not a good basis for password checks based on comparing the password hash in the database with the password hash from the function, with an externally provided password, as the hash in the db might use the new SRP verifier format.
  • For this purpose, use core.check_password_entry instead.

• core.get_player_ip(name): returns an IP address string for the player name.

  • The player needs to be online for this to be successful.

• core.get_auth_handler(): Return the currently active auth handler

  • Must be called after load time, to ensure that any custom auth handler was already registered.
  • See the [Authentication handler definition]
  • Use this to e.g. get the authentication data for a player: local auth_data = core.get_auth_handler().get_auth(playername)

• core.notify_authentication_modified(name)

  • Must be called by the authentication handler for privilege changes.
  • name: string; if omitted, all auth data should be considered modified

• core.set_player_password(name, password_hash): Set password hash of player name.

• core.set_player_privs(name, privs): Set privileges of player name.

  • privs is a set of privileges: A table where the keys are names of privileges and the values are true.
  • Example: core.set_player_privs("singleplayer", {interact = true, fly = true}). This sets the player privileges to interact and fly; singleplayer will only have these two privileges afterwards.

• core.change_player_privs(name, changes): Helper to grant or revoke privileges.

  • changes: Table of changes to make. A field [privname] = true grants a privilege, whereas [privname] = false revokes a privilege.
  • Example: core.change_player_privs("singleplayer", {interact = true, fly = false}) will grant singleplayer the interact privilege and revoke singleplayer's fly privilege. All other privileges will remain unchanged.

• core.auth_reload()

  • See reload() in authentication handler definition

core.set_player_password, core.set_player_privs, core.get_player_privs and core.auth_reload call the authentication handler.

Chat

• core.chat_send_all(text): send chat message to all players
• core.chat_send_player(name, text): send chat message to specific player
  • name: Name of the player
• core.format_chat_message(name, message)
  • Used by the server to format a chat message, based on the setting chat_message_format. Refer to the documentation of the setting for a list of valid placeholders.
  • Takes player name and message, and returns the formatted string to be sent to players.
  • Can be redefined by mods if required, for things like colored names or messages.
  • Only the first occurrence of each placeholder will be replaced.

Environment access

• core.set_node(pos, node)
  • Set node at position pos.
  • Any existing metadata is deleted.
  • node: table {name=string, param1=number, param2=number} If param1 or param2 is omitted, it's set to 0.
  • e.g. core.set_node({x=0, y=10, z=0}, {name="default:wood"})
• core.add_node(pos, node): alias to core.set_node
• core.bulk_set_node({pos1, pos2, pos3, ...}, node)
  • Set the same node at all positions in the first argument.
  • e.g. core.bulk_set_node({{x=0, y=1, z=1}, {x=1, y=2, z=2}}, {name="default:stone"})
  • For node specification or position syntax see core.set_node call
  • Faster than set_node due to single call, but still considerably slower than Lua Voxel Manipulators (LVM) for large numbers of nodes. Unlike LVMs, this will call node callbacks. It also allows setting nodes in spread out positions which would cause LVMs to waste memory. For setting a cube, this is 1.3x faster than set_node whereas LVM is 20 times faster.
• core.swap_node(pos, node)
  • Swap node at position with another.
  • This keeps the metadata intact and will not run con-/destructor callbacks.
• core.bulk_swap_node({pos1, pos2, pos3, ...}, node)
  • Equivalent to core.swap_node but in bulk.
• core.remove_node(pos): Remove a node
  • Equivalent to core.set_node(pos, {name="air"}), but a bit faster.
• core.get_node(pos)
  • Returns the node at the given position as table in the same format as set_node.
  • This function never returns nil and instead returns {name="ignore", param1=0, param2=0} for unloaded areas.
• core.get_node_or_nil(pos)
  • Same as get_node but returns nil for unloaded areas.
  • Note that even loaded areas can contain "ignore" nodes.
• core.get_node_light(pos[, timeofday])
  • Gets the light value at the given position. Note that the light value "inside" the node at the given position is returned, so you usually want to get the light value of a neighbor.
  • pos: The position where to measure the light.
  • timeofday: nil for current time, 0 for night, 0.5 for day
  • Returns a number between 0 and 15 or nil
  • nil is returned e.g. when the map isn't loaded at pos
• core.get_natural_light(pos[, timeofday])
  • Figures out the sunlight (or moonlight) value at pos at the given time of day.
  • pos: The position of the node
  • timeofday: nil for current time, 0 for night, 0.5 for day
  • Returns a number between 0 and 15 or nil
  • This function tests 203 nodes in the worst case, which happens very unlikely
• core.get_artificial_light(param1)
  • Calculates the artificial light (light from e.g. torches) value from the param1 value.
  • param1: The param1 value of a paramtype = "light" node.
  • Returns a number between 0 and 15
  • Currently it's the same as math.floor(param1 / 16), except that it ensures compatibility.
• core.place_node(pos, node[, placer])
  • Place node with the same effects that a player would cause
  • placer: The ObjectRef that places the node (optional)
• core.dig_node(pos[, digger])
  • Dig node with the same effects that a player would cause
  • digger: The ObjectRef that digs the node (optional)
  • Returns true if successful, false on failure (e.g. protected location)
• core.punch_node(pos[, puncher])
  • Punch node with the same effects that a player would cause
  • puncher: The ObjectRef that punches the node (optional)

• core.spawn_falling_node(pos)

  • Change node into falling node
  • Returns true and the ObjectRef of the spawned entity if successful, false on failure

• core.find_nodes_with_meta(pos1, pos2)

  • Get a table of positions of nodes that have metadata within a region {pos1, pos2}.

• core.get_meta(pos)

  • Get a NodeMetaRef at that position

• core.get_node_timer(pos)

  • Get NodeTimerRef

• core.add_entity(pos, name, [staticdata]): Spawn Lua-defined entity at position.

  • Returns ObjectRef, or nil if failed
  • Entities with static_save = true can be added also to unloaded and non-generated blocks.

• core.add_item(pos, item): Spawn item

  • Returns ObjectRef, or nil if failed
  • Items can be added also to unloaded and non-generated blocks.

• core.get_player_by_name(name): Get an ObjectRef to a player

  • Returns nothing in case of error (player offline, doesn't exist, ...).

• core.get_objects_inside_radius(center, radius)

  • returns a list of ObjectRefs
  • radius: using a Euclidean metric
  • Warning: Any kind of interaction with the environment or other APIs can cause later objects in the list to become invalid while you're iterating it. (e.g. punching an entity removes its children) It is recommended to use core.objects_inside_radius instead, which transparently takes care of this possibility.

• core.objects_inside_radius(center, radius)

  • returns an iterator of valid objects
  • example: for obj in core.objects_inside_radius(center, radius) do obj:punch(...) end

• core.get_objects_in_area(min_pos, max_pos)

  • returns a list of ObjectRefs
  • min_pos and max_pos are the min and max positions of the area to search
  • Warning: The same warning as for core.get_objects_inside_radius applies. Use core.objects_in_area instead to iterate only valid objects.

• core.objects_in_area(min_pos, max_pos)

  • returns an iterator of valid objects

• core.set_timeofday(val): set time of day

  • val is between 0 and 1; 0 for midnight, 0.5 for midday

• core.get_timeofday(): get time of day

• core.get_gametime(): returns the time, in seconds, since the world was created. The time is not available (nil) before the first server step.

• core.get_day_count(): returns number days elapsed since world was created.

  • Time changes are accounted for.

• core.find_node_near(pos, radius, nodenames, [search_center]): returns pos or nil.

  • radius: using a maximum metric
  • nodenames: e.g. {"ignore", "group:tree"} or "default:dirt"
  • search_center is an optional boolean (default: false) If true pos is also checked for the nodes

• core.find_nodes_in_area(pos1, pos2, nodenames, [grouped])

  • pos1 and pos2 are the min and max positions of the area to search.
  • nodenames: e.g. {"ignore", "group:tree"} or "default:dirt"
  • If grouped is true the return value is a table indexed by node name which contains lists of positions.
  • If grouped is false or absent the return values are as follows: first value: Table with all node positions second value: Table with the count of each node with the node name as index
  • Area volume is limited to 4,096,000 nodes

• core.find_nodes_in_area_under_air(pos1, pos2, nodenames): returns a list of positions.

  • nodenames: e.g. {"ignore", "group:tree"} or "default:dirt"
  • Return value: Table with all node positions with a node air above
  • Area volume is limited to 4,096,000 nodes

• core.get_perlin(noiseparams)

  • Return world-specific perlin noise.
  • The actual seed used is the noiseparams seed plus the world seed.

• core.get_perlin(seeddiff, octaves, persistence, spread)

  • Deprecated: use core.get_perlin(noiseparams) instead.
  • Return world-specific perlin noise.

• core.get_voxel_manip([pos1, pos2])

  • Return voxel manipulator object.
  • Loads the manipulator from the map if positions are passed.

• core.set_gen_notify(flags, [deco_ids], [custom_ids])

  • Set the types of on-generate notifications that should be collected.
  • flags: flag field, see [gennotify] for available generation notification types.
  • The following parameters are optional:
  • deco_ids is a list of IDs of decorations which notification is requested for.
  • custom_ids is a list of user-defined IDs (strings) which are requested. By convention these should be the mod name with an optional colon and specifier added, e.g. "default" or "default:dungeon_loot"

• core.get_gen_notify()

  • Returns a flagstring, a table with the deco_ids and a table with user-defined IDs.

• core.get_decoration_id(decoration_name)

  • Returns the decoration ID number for the provided decoration name string, or nil on failure.

• core.get_mapgen_object(objectname)

  • Return requested mapgen object if available (see [Mapgen objects])

• core.get_heat(pos)

  • Returns the heat at the position, or nil on failure.

• core.get_humidity(pos)

  • Returns the humidity at the position, or nil on failure.

• core.get_biome_data(pos)

  • Returns a table containing:
    • biome the biome id of the biome at that position
    • heat the heat at the position
    • humidity the humidity at the position
  • Or returns nil on failure.

• core.get_biome_id(biome_name)

  • Returns the biome id, as used in the biomemap Mapgen object and returned by core.get_biome_data(pos), for a given biome_name string.

• core.get_biome_name(biome_id)

  • Returns the biome name string for the provided biome id, or nil on failure.
  • If no biomes have been registered, such as in mgv6, returns default.

• core.get_mapgen_params()

  • Deprecated: use core.get_mapgen_setting(name) instead.
  • Returns a table containing:
    • mgname
    • seed
    • chunksize
    • water_level
    • flags

• core.set_mapgen_params(MapgenParams)

  • Deprecated: use core.set_mapgen_setting(name, value, override) instead.
  • Set map generation parameters.
  • Function cannot be called after the registration period.
  • Takes a table as an argument with the fields:
    • mgname
    • seed
    • chunksize
    • water_level
    • flags
  • Leave field unset to leave that parameter unchanged.
  • flags contains a comma-delimited string of flags to set, or if the prefix "no" is attached, clears instead.
  • flags is in the same format and has the same options as mg_flags in minetest.conf.

• core.get_mapgen_edges([mapgen_limit[, chunksize]])

  • Returns the minimum and maximum possible generated node positions in that order.
  • mapgen_limit is an optional number. If it is absent, its value is that of the active mapgen setting "mapgen_limit".
  • chunksize is an optional number. If it is absent, its value is that of the active mapgen setting "chunksize".

• core.get_mapgen_setting(name)

  • Gets the active mapgen setting (or nil if none exists) in string format with the following order of precedence: 1) Settings loaded from map_meta.txt or overrides set during mod execution. 2) Settings set by mods without a metafile override 3) Settings explicitly set in the user config file, minetest.conf 4) Settings set as the user config default

• core.get_mapgen_setting_noiseparams(name)

  • Same as above, but returns the value as a NoiseParams table if the setting name exists and is a valid NoiseParams.

• core.set_mapgen_setting(name, value, [override_meta])

  • Sets a mapgen param to value, and will take effect if the corresponding mapgen setting is not already present in map_meta.txt.
  • override_meta is an optional boolean (default: false). If this is set to true, the setting will become the active setting regardless of the map metafile contents.
  • Note: to set the seed, use "seed", not "fixed_map_seed".

• core.set_mapgen_setting_noiseparams(name, value, [override_meta])

  • Same as above, except value is a NoiseParams table.

• core.set_noiseparams(name, noiseparams, set_default)

  • Sets the noiseparams setting of name to the noiseparams table specified in noiseparams.
  • set_default is an optional boolean (default: true) that specifies whether the setting should be applied to the default config or current active config.

• core.get_noiseparams(name)

  • Returns a table of the noiseparams for name.

• core.generate_ores(vm, pos1, pos2)

  • Generate all registered ores within the VoxelManip vm and in the area from pos1 to pos2.
  • pos1 and pos2 are optional and default to mapchunk minp and maxp.

• core.generate_decorations(vm, pos1, pos2)

  • Generate all registered decorations within the VoxelManip vm and in the area from pos1 to pos2.
  • pos1 and pos2 are optional and default to mapchunk minp and maxp.

• core.clear_objects([options])

  • Clear all objects in the environment
  • Takes an optional table as an argument with the field mode.
    • mode = "full": Load and go through every mapblock, clearing objects (default).
    • mode = "quick": Clear objects immediately in loaded mapblocks, clear objects in unloaded mapblocks only when the mapblocks are next activated.

• core.load_area(pos1[, pos2])

  • Load the mapblocks containing the area from pos1 to pos2. pos2 defaults to pos1 if not specified.
  • This function does not trigger map generation.

• core.emerge_area(pos1, pos2, [callback], [param])

  • Queue all blocks in the area from pos1 to pos2, inclusive, to be asynchronously fetched from memory, loaded from disk, or if inexistent, generates them.
  • If callback is a valid Lua function, this will be called for each block emerged.
  • The function signature of callback is: function EmergeAreaCallback(blockpos, action, calls_remaining, param)
    • blockpos is the block coordinates of the block that had been emerged.
    • action could be one of the following constant values:
      • core.EMERGE_CANCELLED
      • core.EMERGE_ERRORED
      • core.EMERGE_FROM_MEMORY
      • core.EMERGE_FROM_DISK
      • core.EMERGE_GENERATED
    • calls_remaining is the number of callbacks to be expected after this one.
    • param is the user-defined parameter passed to emerge_area (or nil if the parameter was absent).

• core.delete_area(pos1, pos2)

  • delete all mapblocks in the area from pos1 to pos2, inclusive

• core.line_of_sight(pos1, pos2): returns boolean, pos

  • Checks if there is anything other than air between pos1 and pos2.
  • Returns false if something is blocking the sight.
  • Returns the position of the blocking node when false
  • pos1: First position
  • pos2: Second position

• core.raycast(pos1, pos2, objects, liquids, pointabilities): returns Raycast

  • Creates a Raycast object.
  • pos1: start of the ray
  • pos2: end of the ray
  • objects: if false, only nodes will be returned. Default is true.
  • liquids: if false, liquid nodes (liquidtype ~= "none") won't be returned. Default is false.
  • pointabilities: Allows overriding the pointable property of nodes and objects. Uses the same format as the pointabilities property of item definitions. Default is nil.

• core.find_path(pos1,pos2,searchdistance,max_jump,max_drop,algorithm)

  • returns table containing path that can be walked on
  • returns a table of 3D points representing a path from pos1 to pos2 or nil on failure.
  • Reasons for failure:
    • No path exists at all
    • No path exists within searchdistance (see below)
    • Start or end pos is buried in land
  • pos1: start position
  • pos2: end position
  • searchdistance: maximum distance from the search positions to search in. In detail: Path must be completely inside a cuboid. The minimum searchdistance of 1 will confine search between pos1 and pos2. Larger values will increase the size of this cuboid in all directions
  • max_jump: maximum height difference to consider walkable
  • max_drop: maximum height difference to consider droppable
  • algorithm: One of "A*_noprefetch" (default), "A*", "Dijkstra". Difference between "A*" and "A*_noprefetch" is that "A*" will pre-calculate the cost-data, the other will calculate it on-the-fly

• core.spawn_tree (pos, {treedef})

  • spawns L-system tree at given pos with definition in treedef table

• core.spawn_tree_on_vmanip(vmanip, pos, treedef)

  • analogous to core.spawn_tree, but spawns a L-system tree onto the specified VoxelManip object vmanip instead of the map.

• core.transforming_liquid_add(pos)

  • add node to liquid flow update queue

• core.get_node_max_level(pos)

  • get max available level for leveled node

• core.get_node_level(pos)

  • get level of leveled node (water, snow)

• core.set_node_level(pos, level)

  • set level of leveled node, default level equals 1
  • if totallevel > maxlevel, returns rest (total-max).

• core.add_node_level(pos, level)

  • increase level of leveled node by level, default level equals 1
  • if totallevel > maxlevel, returns rest (total-max)
  • level must be between -127 and 127

• core.get_node_boxes(box_type, pos, [node])

  • box_type must be "node_box", "collision_box" or "selection_box".
  • pos must be a node position.
  • node can be a table in the form {name=string, param1=number, param2=number}. If node is nil, the actual node at pos is used instead.
  • Resolves any facedir-rotated boxes, connected boxes and the like into actual boxes.
  • Returns a list of boxes in the form {{x1, y1, z1, x2, y2, z2}, {x1, y1, z1, x2, y2, z2}, ...}. Coordinates are relative to pos.
  • See also: Node boxes

• core.fix_light(pos1, pos2): returns true/false

  • resets the light in a cuboid-shaped part of the map and removes lighting bugs.
  • Loads the area if it is not loaded.
  • pos1 is the corner of the cuboid with the least coordinates (in node coordinates), inclusive.
  • pos2 is the opposite corner of the cuboid, inclusive.
  • The actual updated cuboid might be larger than the specified one, because only whole map blocks can be updated. The actual updated area consists of those map blocks that intersect with the given cuboid.
  • However, the neighborhood of the updated area might change as well, as light can spread out of the cuboid, also light might be removed.
  • returns false if the area is not fully generated, true otherwise

• core.check_single_for_falling(pos)

  • causes an unsupported group:falling_node node to fall and causes an unattached group:attached_node node to fall.
  • does not spread these updates to neighbors.

• core.check_for_falling(pos)

  • causes an unsupported group:falling_node node to fall and causes an unattached group:attached_node node to fall.
  • spread these updates to neighbors and can cause a cascade of nodes to fall.

• core.get_spawn_level(x, z)

  • Returns a player spawn y coordinate for the provided (x, z) coordinates, or nil for an unsuitable spawn point.
  • For most mapgens a 'suitable spawn point' is one with y between water_level and water_level + 16, and in mgv7 well away from rivers, so nil will be returned for many (x, z) coordinates.
  • The spawn level returned is for a player spawn in unmodified terrain.
  • The spawn level is intentionally above terrain level to cope with full-node biome 'dust' nodes.

Mod channels

You can find mod channels communication scheme in doc/mod_channels.png.

• core.mod_channel_join(channel_name)
  • Server joins channel channel_name, and creates it if necessary. You should listen for incoming messages with core.register_on_modchannel_message

Inventory

core.get_inventory(location): returns an InvRef

• location = e.g.
  • {type="player", name="celeron55"}
  • {type="node", pos={x=, y=, z=}}
  • {type="detached", name="creative"}
• core.create_detached_inventory(name, callbacks, [player_name]): returns an InvRef.
  • callbacks: See [Detached inventory callbacks]
  • player_name: Make detached inventory available to one player exclusively, by default they will be sent to every player (even if not used). Note that this parameter is mostly just a workaround and will be removed in future releases.
  • Creates a detached inventory. If it already exists, it is cleared.
• core.remove_detached_inventory(name)
  • Returns a boolean indicating whether the removal succeeded.
• core.do_item_eat(hp_change, replace_with_item, itemstack, user, pointed_thing): returns leftover ItemStack or nil to indicate no inventory change
  • See core.item_eat and core.register_on_item_eat

Formspec

• core.show_formspec(playername, formname, formspec)
  • playername: name of player to show formspec
  • formname: name passed to on_player_receive_fields callbacks. It should follow the "modname:<whatever>" naming convention.
  • formname must not be empty, unless you want to reshow the inventory formspec without updating it for future opens.
  • formspec: formspec to display
• core.close_formspec(playername, formname)
  • playername: name of player to close formspec
  • formname: has to exactly match the one given in show_formspec, or the formspec will not close.
  • calling show_formspec(playername, formname, "") is equal to this expression.
  • to close a formspec regardless of the formname, call core.close_formspec(playername, ""). USE THIS ONLY WHEN ABSOLUTELY NECESSARY!
• core.formspec_escape(string): returns a string
  • escapes the characters "[", "]", "\", "," and ";", which cannot be used in formspecs.
• core.hypertext_escape(string): returns a string
  • escapes the characters "\", "<", and ">" to show text in a hypertext element.
  • not safe for use with tag attributes.
  • this function does not do formspec escaping, you will likely need to do core.formspec_escape(core.hypertext_escape(string)) if the hypertext is not already being formspec escaped.
• core.explode_table_event(string): returns a table
  • returns e.g. {type="CHG", row=1, column=2}
  • type is one of:
    • "INV": no row selected
    • "CHG": selected
    • "DCL": double-click
• core.explode_textlist_event(string): returns a table
  • returns e.g. {type="CHG", index=1}
  • type is one of:
    • "INV": no row selected
    • "CHG": selected
    • "DCL": double-click
• core.explode_scrollbar_event(string): returns a table
  • returns e.g. {type="CHG", value=500}
  • type is one of:
    • "INV": something failed
    • "CHG": has been changed
    • "VAL": not changed
• core.show_death_screen(player, reason)
  • Called when the death screen should be shown.
  • player is an ObjectRef, reason is a PlayerHPChangeReason table or nil.
  • By default, this shows a simple formspec with the option to respawn. Respawning is done via ObjectRef:respawn.
  • You can override this to show a custom death screen.
  • For general death handling, use core.register_on_dieplayer instead.

Item handling

• core.inventorycube(img1, img2, img3)
  • Returns a string for making an image of a cube (useful as an item image)
• core.get_pointed_thing_position(pointed_thing, above)
  • Returns the position of a pointed_thing or nil if the pointed_thing does not refer to a node or entity.
  • If the optional above parameter is true and the pointed_thing refers to a node, then it will return the above position of the pointed_thing.
• core.dir_to_facedir(dir, is6d)
  • Convert a vector to a facedir value, used in param2 for paramtype2="facedir".
  • passing something non-nil/false for the optional second parameter causes it to take the y component into account.
• core.facedir_to_dir(facedir)
  • Convert a facedir back into a vector aimed directly out the "back" of a node.
• core.dir_to_fourdir(dir)
  • Convert a vector to a 4dir value, used in param2 for paramtype2="4dir".
• core.fourdir_to_dir(fourdir)
  • Convert a 4dir back into a vector aimed directly out the "back" of a node.
• core.dir_to_wallmounted(dir)
  • Convert a vector to a wallmounted value, used for paramtype2="wallmounted".
• core.wallmounted_to_dir(wallmounted)
  • Convert a wallmounted value back into a vector aimed directly out the "back" of a node.
• core.dir_to_yaw(dir)
  • Convert a vector into a yaw (angle)
• core.yaw_to_dir(yaw)
  • Convert yaw (angle) to a vector
• core.is_colored_paramtype(ptype)
  • Returns a boolean. Returns true if the given paramtype2 contains color information (color, colorwallmounted, colorfacedir, etc.).
• core.strip_param2_color(param2, paramtype2)
  • Removes everything but the color information from the given param2 value.
  • Returns nil if the given paramtype2 does not contain color information.
• core.get_node_drops(node, toolname)
  • Returns list of itemstrings that are dropped by node when dug with the item toolname (not limited to tools).
  • node: node as table or node name
  • toolname: name of the item used to dig (can be nil)
• core.get_craft_result(input): returns output, decremented_input
  • input.method = "normal" or "cooking" or "fuel"
  • input.width = for example 3
  • input.items = for example {stack1, stack2, stack3, stack4, stack 5, stack 6, stack 7, stack 8, stack 9}
  • output.item = ItemStack, if unsuccessful: empty ItemStack
  • output.time = a number, if unsuccessful: 0
  • output.replacements = List of replacement ItemStacks that couldn't be placed in decremented_input.items. Replacements can be placed in decremented_input if the stack of the replaced item has a count of 1.
  • decremented_input = like input
• core.get_craft_recipe(output): returns input
  • returns last registered recipe for output item (node)
  • output is a node or item type such as "default:torch"
  • input.method = "normal" or "cooking" or "fuel"
  • input.width = for example 3
  • input.items = for example {stack1, stack2, stack3, stack4, stack 5, stack 6, stack 7, stack 8, stack 9}
    • input.items = nil if no recipe found

• core.get_all_craft_recipes(query item): returns a table or nil

  • returns indexed table with all registered recipes for query item (node) or nil if no recipe was found.
  • recipe entry table:
    • method: 'normal' or 'cooking' or 'fuel'
    • width: 0-3, 0 means shapeless recipe
    • items: indexed [1-9] table with recipe items
    • output: string with item name and quantity
  • Example result for "default:gold_ingot" with two recipes: lua { { method = "cooking", width = 3, output = "default:gold_ingot", items = {"default:gold_lump"} }, { method = "normal", width = 1, output = "default:gold_ingot 9", items = {"default:goldblock"} } }

• core.handle_node_drops(pos, drops, digger)

  • drops: list of itemstrings
  • Handles drops from nodes after digging: Default action is to put them into digger's inventory.
  • Can be overridden to get different functionality (e.g. dropping items on ground)

• core.itemstring_with_palette(item, palette_index): returns an item string.

  • Creates an item string which contains palette index information for hardware colorization. You can use the returned string as an output in a craft recipe.
  • item: the item stack which becomes colored. Can be in string, table and native form.
  • palette_index: this index is added to the item stack

• core.itemstring_with_color(item, colorstring): returns an item string

  • Creates an item string which contains static color information for hardware colorization. Use this method if you wish to colorize an item that does not own a palette. You can use the returned string as an output in a craft recipe.
  • item: the item stack which becomes colored. Can be in string, table and native form.
  • colorstring: the new color of the item stack

Rollback

• core.rollback_get_node_actions(pos, range, seconds, limit): returns {{actor, pos, time, oldnode, newnode}, ...}
  • Find who has done something to a node, or near a node
  • actor: "player:<name>", also "liquid".
• core.rollback_revert_actions_by(actor, seconds): returns boolean, log_messages.
  • Revert latest actions of someone
  • actor: "player:<name>", also "liquid".

Defaults for the on_place and on_drop item definition functions

• core.item_place_node(itemstack, placer, pointed_thing[, param2, prevent_after_place])
  • Place item as a node
  • param2 overrides facedir and wallmounted param2
  • prevent_after_place: if set to true, after_place_node is not called for the newly placed node to prevent a callback and placement loop
  • returns itemstack, position
    • position: the location the node was placed to. nil if nothing was placed.
• core.item_place_object(itemstack, placer, pointed_thing)
  • Place item as-is
  • returns the leftover itemstack
  • Note: This function is deprecated and will never be called.
• core.item_place(itemstack, placer, pointed_thing[, param2])
  • Wrapper that calls core.item_place_node if appropriate
  • Calls on_rightclick of pointed_thing.under if defined instead
  • Note: is not called when wielded item overrides on_place
  • param2 overrides facedir and wallmounted param2
  • returns itemstack, position
    • position: the location the node was placed to. nil if nothing was placed.
• core.item_pickup(itemstack, picker, pointed_thing, time_from_last_punch, ...)
  • Runs callbacks registered by core.register_on_item_pickup and adds the item to the picker's "main" inventory list.
  • Parameters are the same as in on_pickup.
  • Returns the leftover itemstack.
• core.item_drop(itemstack, dropper, pos)
  • Drop the item
  • returns the leftover itemstack
• core.item_eat(hp_change[, replace_with_item])
  • Returns function(itemstack, user, pointed_thing) as a function wrapper for core.do_item_eat.
  • replace_with_item is the itemstring which is added to the inventory. If the player is eating a stack and replace_with_item doesn't fit onto the eaten stack, then the remainings go to a different spot, or are dropped.

Defaults for the on_punch and on_dig node definition callbacks

• core.node_punch(pos, node, puncher, pointed_thing)
  • Calls functions registered by core.register_on_punchnode()
• core.node_dig(pos, node, digger)
  • Checks if node can be dug, puts item into inventory, removes node
  • Calls functions registered by core.registered_on_dignodes()

Sounds

• core.sound_play(spec, parameters, [ephemeral]): returns a handle
  • spec is a SimpleSoundSpec
  • parameters is a sound parameter table
  • ephemeral is a boolean (default: false) Ephemeral sounds will not return a handle and can't be stopped or faded. It is recommend to use this for short sounds that happen in response to player actions (e.g. door closing).
• core.sound_stop(handle)
  • handle is a handle returned by core.sound_play
• core.sound_fade(handle, step, gain)
  • handle is a handle returned by core.sound_play
  • step determines how fast a sound will fade. The gain will change by this much per second, until it reaches the target gain. Note: Older versions used a signed step. This is deprecated, but old code will still work. (the client uses abs(step) to correct it)
  • gain the target gain for the fade. Fading to zero will delete the sound.

Timing

• core.after(time, func, ...): returns job table to use as below.

  • Call the function func after time seconds, may be fractional
  • Optional: Variable number of arguments that are passed to func
  • Jobs set for earlier times are executed earlier. If multiple jobs expire at exactly the same time, then they are executed in registration order.
  • time is a lower bound. The job is executed in the first server-step that started at least time seconds after the last time a server-step started, measured with globalstep dtime.
  • If time is 0, the job is executed in the next step.

• job:cancel()

  • Cancels the job function from being called

Async environment

The engine allows you to submit jobs to be ran in an isolated environment concurrently with normal server operation. A job consists of a function to be ran in the async environment, any amount of arguments (will be serialized) and a callback that will be called with the return value of the job function once it is finished.

The async environment does not have access to the map, entities, players or any globals defined in the 'usual' environment. Consequently, functions like core.get_node() or core.get_player_by_name() simply do not exist in it.

Arguments and return values passed through this can contain certain userdata objects that will be seamlessly copied (not shared) to the async environment. This allows you easy interoperability for delegating work to jobs.

• core.handle_async(func, callback, ...):
  • Queue the function func to be ran in an async environment. Note that there are multiple persistent workers and any of them may end up running a given job. The engine will scale the amount of worker threads automatically.
  • When func returns the callback is called (in the normal environment) with all of the return values as arguments.
  • Optional: Variable number of arguments that are passed to func
• core.register_async_dofile(path):
  • Register a path to a Lua file to be imported when an async environment is initialized. You can use this to preload code which you can then call later using core.handle_async().

List of APIs available in an async environment

Classes:

• AreaStore
• ItemStack
• PerlinNoise
• PerlinNoiseMap
• PseudoRandom
• PcgRandom
• SecureRandom
• VoxelArea
• VoxelManip
  • only if transferred into environment; can't read/write to map
• Settings

Class instances that can be transferred between environments:

• ItemStack
• PerlinNoise
• PerlinNoiseMap
• VoxelManip

Functions:

• Standalone helpers such as logging, filesystem, encoding, hashing or compression APIs
• core.register_portable_metatable
• IPC

Variables:

• core.settings
• core.registered_items, registered_nodes, registered_tools, registered_craftitems and registered_aliases
  • with all functions and userdata values replaced by true, calling any callbacks here is obviously not possible

Mapgen environment

The engine runs the map generator on separate threads, each of these also has a Lua environment. Its primary purpose is to allow mods to operate on newly generated parts of the map to e.g. generate custom structures. Internally it is referred to as "emerge environment".

Refer to [Async environment] for the usual disclaimer on what environment isolation entails.

The map generator threads, which also contain the above mentioned Lua environment, are initialized after all mods have been loaded by the server. After that the registered scripts (not all mods!) - see below - are run during initialization of the mapgen environment. After that only callbacks happen. The mapgen env does not have a global step or timer.

• core.register_mapgen_script(path):
  • Register a path to a Lua file to be imported when a mapgen environment is initialized. Run in order of registration.

List of APIs exclusive to the mapgen env

• core.register_on_generated(function(vmanip, minp, maxp, blockseed))
  • Called after the engine mapgen finishes a chunk but before it is written to the map.
  • Chunk data resides in vmanip. Other parts of the map are not accessible. The area of the chunk if comprised of minp and maxp, note that is smaller than the emerged area of the VoxelManip. Note: calling read_from_map() or write_to_map() on the VoxelManipulator object is not necessary and is disallowed.
  • blockseed: 64-bit seed number used for this chunk
• core.save_gen_notify(id, data)
  • Saves data for retrieval using the gennotify mechanism (see [Mapgen objects]).
  • Data is bound to the chunk that is currently being processed, so this function only makes sense inside the on_generated callback.
  • id: user-defined ID (a string) By convention these should be the mod name with an optional colon and specifier added, e.g. "default" or "default:dungeon_loot"
  • data: any Lua object (will be serialized, no userdata allowed)
  • returns true if the data was remembered. That is if core.set_gen_notify was called with the same user-defined ID before.

List of APIs available in the mapgen env

Classes:

• AreaStore
• ItemStack
• PerlinNoise
• PerlinNoiseMap
• PseudoRandom
• PcgRandom
• SecureRandom
• VoxelArea
• VoxelManip
  • only given by callbacks; cannot access rest of map
• Settings

Functions:

• Standalone helpers such as logging, filesystem, encoding, hashing or compression APIs
• core.get_biome_id, get_biome_name, get_heat, get_humidity, get_biome_data, get_mapgen_object, get_mapgen_params, get_mapgen_edges, get_mapgen_setting, get_noiseparams, get_decoration_id and more
• core.get_node, set_node, find_node_near, find_nodes_in_area, spawn_tree and similar
  • these only operate on the current chunk (if inside a callback)
• IPC

Variables:

• core.settings
• core.registered_items, registered_nodes, registered_tools, registered_craftitems and registered_aliases
  • with all functions and userdata values replaced by true, calling any callbacks here is obviously not possible
• core.registered_biomes, registered_ores, registered_decorations

Note that node metadata does not exist in the mapgen env, we suggest deferring setting any metadata you need to the on_generated callback in the regular env. You can use the gennotify mechanism to transfer this information.

Server

• core.request_shutdown([message],[reconnect],[delay]): request for server shutdown. Will display message to clients.
  • reconnect == true displays a reconnect button
  • delay adds an optional delay (in seconds) before shutdown. Negative delay cancels the current active shutdown. Zero delay triggers an immediate shutdown.
• core.cancel_shutdown_requests(): cancel current delayed shutdown
• core.get_server_status(name, joined)
  • Returns the server status string when a player joins or when the command /status is called. Returns nil or an empty string when the message is disabled.
  • joined: Boolean value, indicates whether the function was called when a player joined.
  • This function may be overwritten by mods to customize the status message.
• core.get_server_uptime(): returns the server uptime in seconds
• core.get_server_max_lag(): returns the current maximum lag of the server in seconds or nil if server is not fully loaded yet
• core.remove_player(name): remove player from database (if they are not connected).
  • As auth data is not removed, core.player_exists will continue to return true. Call the below method as well if you want to remove auth data too.
  • Returns a code (0: successful, 1: no such player, 2: player is connected)
• core.remove_player_auth(name): remove player authentication data
  • Returns boolean indicating success (false if player nonexistent)
• core.dynamic_add_media(options, callback)
  • options: table containing the following parameters
    • filename: name the media file will be usable as (optional if filepath present)
    • filepath: path to the file on the filesystem [*]
    • filedata: the data of the file to be sent [*]
    • to_player: name of the player the media should be sent to instead of all players (optional)
    • ephemeral: boolean that marks the media as ephemeral, it will not be cached on the client (optional, default false)
    • Exactly one of the parameters marked [*] must be specified.
  • callback: function with arguments name, which is a player name
  • Pushes the specified media file to client(s). (details below) The file must be a supported image, sound or model format. Dynamically added media is not persisted between server restarts.
  • Returns false on error, true if the request was accepted
  • The given callback will be called for every player as soon as the media is available on the client.
  • Details/Notes:
    • If ephemeral=false and to_player is unset the file is added to the media sent to clients on startup, this means the media will appear even on old clients if they rejoin the server.
    • If ephemeral=false the file must not be modified, deleted, moved or renamed after calling this function.
    • Regardless of any use of ephemeral, adding media files with the same name twice is not possible/guaranteed to work. An exception to this is the use of to_player to send the same, already existent file to multiple chosen players.
    • You can also call this at startup time. In that case callback MUST be nil and you cannot use ephemeral or to_player, as these logically do not make sense.
  • Clients will attempt to fetch files added this way via remote media, this can make transfer of bigger files painless (if set up). Nevertheless it is advised not to use dynamic media for big media files.

IPC

The engine provides a generalized mechanism to enable sharing data between the different Lua environments (main, mapgen and async). It is essentially a shared in-memory key-value store.

• core.ipc_get(key):
  • Read a value from the shared data area.
  • key: string, should use the "modname:thing" convention to avoid conflicts.
  • returns an arbitrary Lua value, or nil if this key does not exist
• core.ipc_set(key, value):
  • Write a value to the shared data area.
  • key: as above
  • value: an arbitrary Lua value, cannot be or contain userdata.

Interacting with the shared data will perform an operation comparable to (de)serialization on each access. For that reason modifying references will not have any effect, as in this example:

core.ipc_set("test:foo", {})
core.ipc_get("test:foo").subkey = "value" -- WRONG!
core.ipc_get("test:foo") -- returns an empty table

Advanced:

• core.ipc_cas(key, old_value, new_value):
  • Write a value to the shared data area, but only if the previous value equals what was given. This operation is called Compare-and-Swap and can be used to implement synchronization between threads.
  • key: as above
  • old_value: value compared to using == (nil compares equal for non-existing keys)
  • new_value: value that will be set
  • returns: true on success, false otherwise
• core.ipc_poll(key, timeout):
  • Do a blocking wait until a value (other than nil) is present at the key.
  • IMPORTANT: You usually don't need this function. Use this as a last resort if nothing else can satisfy your use case! None of the Lua environments the engine has are safe to block for extended periods, especially on the main thread any delays directly translate to lag felt by players.
  • key: as above
  • timeout: maximum wait time, in milliseconds (positive values only)
  • returns: true on success, false on timeout

Bans

• core.get_ban_list(): returns a list of all bans formatted as string
• core.get_ban_description(ip_or_name): returns list of bans matching IP address or name formatted as string
• core.ban_player(name): ban the IP of a currently connected player
  • Returns boolean indicating success
• core.unban_player_or_ip(ip_or_name): remove ban record matching IP address or name
• core.kick_player(name[, reason[, reconnect]]): disconnect a player with an optional reason.
  • Returns boolean indicating success (false if player nonexistent)
  • If reconnect is true, allow the user to reconnect.
• core.disconnect_player(name[, reason[, reconnect]]): disconnect a player with an optional reason, this will not prefix with 'Kicked: ' like kick_player. If no reason is given, it will default to 'Disconnected.'
  • Returns boolean indicating success (false if player nonexistent)

Particles

• core.add_particle(particle definition)

  • Deprecated: core.add_particle(pos, velocity, acceleration, expirationtime, size, collisiondetection, texture, playername)

• core.add_particlespawner(particlespawner definition)

  • Add a ParticleSpawner, an object that spawns an amount of particles over time seconds.
  • Returns an id, and -1 if adding didn't succeed
  • Deprecated: core.add_particlespawner(amount, time, minpos, maxpos, minvel, maxvel, minacc, maxacc, minexptime, maxexptime, minsize, maxsize, collisiondetection, texture, playername)

• core.delete_particlespawner(id, player)

  • Delete ParticleSpawner with id (return value from core.add_particlespawner).
  • If playername is specified, only deletes on the player's client, otherwise on all clients.

Schematics

• core.create_schematic(p1, p2, probability_list, filename, slice_prob_list)

  • Create a schematic from the volume of map specified by the box formed by p1 and p2.
  • Apply the specified probability and per-node force-place to the specified nodes according to the probability_list.
    • probability_list is an array of tables containing two fields, pos and prob.
      • pos is the 3D vector specifying the absolute coordinates of the node being modified,
      • prob is an integer value from 0 to 255 that encodes probability and per-node force-place. Probability has levels 0-127, then 128 may be added to encode per-node force-place. For probability stated as 0-255, divide by 2 and round down to get values 0-127, then add 128 to apply per-node force-place.
      • If there are two or more entries with the same pos value, the last entry is used.
      • If pos is not inside the box formed by p1 and p2, it is ignored.
      • If probability_list equals nil, no probabilities are applied.
  • Apply the specified probability to the specified horizontal slices according to the slice_prob_list.
    • slice_prob_list is an array of tables containing two fields, ypos and prob.
      • ypos indicates the y position of the slice with a probability applied, the lowest slice being ypos = 0.
      • If slice probability list equals nil, no slice probabilities are applied.
  • Saves schematic in the Luanti Schematic format to filename.

• core.place_schematic(pos, schematic, rotation, replacements, force_placement, flags)

  • Place the schematic specified by schematic (see [Schematic specifier]) at pos.
  • rotation can equal "0", "90", "180", "270", or "random".
  • If the rotation parameter is omitted, the schematic is not rotated.
  • replacements = {["old_name"] = "convert_to", ...}
  • force_placement is a boolean indicating whether nodes other than air and ignore are replaced by the schematic.
  • Returns nil if the schematic could not be loaded.
  • Warning: Once you have loaded a schematic from a file, it will be cached. Future calls will always use the cached version and the replacement list defined for it, regardless of whether the file or the replacement list parameter have changed. The only way to load the file anew is to restart the server.
  • flags is a flag field with the available flags:
    • place_center_x
    • place_center_y
    • place_center_z

• core.place_schematic_on_vmanip(vmanip, pos, schematic, rotation, replacement, force_placement, flags):

  • This function is analogous to core.place_schematic, but places a schematic onto the specified VoxelManip object vmanip instead of the map.
  • Returns false if any part of the schematic was cut-off due to the VoxelManip not containing the full area required, and true if the whole schematic was able to fit.
  • Returns nil if the schematic could not be loaded.
  • After execution, any external copies of the VoxelManip contents are invalidated.
  • flags is a flag field with the available flags:
    • place_center_x
    • place_center_y
    • place_center_z

• core.serialize_schematic(schematic, format, options)

  • Return the serialized schematic specified by schematic (see [Schematic specifier])
  • in the format of either "mts" or "lua".
  • "mts" - a string containing the binary MTS data used in the MTS file format.
  • "lua" - a string containing Lua code representing the schematic in table format.
  • options is a table containing the following optional parameters:
    • If lua_use_comments is true and format is "lua", the Lua code generated will have (X, Z) position comments for every X row generated in the schematic data for easier reading.
    • If lua_num_indent_spaces is a nonzero number and format is "lua", the Lua code generated will use that number of spaces as indentation instead of a tab character.

• core.read_schematic(schematic, options)

  • Returns a Lua table representing the schematic (see: [Schematic specifier])
  • schematic is the schematic to read (see: [Schematic specifier])
  • options is a table containing the following optional parameters:
    • write_yslice_prob: string value:
      • none: no write_yslice_prob table is inserted,
      • low: only probabilities that are not 254 or 255 are written in the write_ylisce_prob table,
      • all: write all probabilities to the write_yslice_prob table.
      • The default for this option is all.
      • Any invalid value will be interpreted as all.

HTTP Requests

• core.request_http_api():
  • returns HTTPApiTable containing http functions if the calling mod has been granted access by being listed in the secure.http_mods or secure.trusted_mods setting, otherwise returns nil.
  • The returned table contains the functions fetch, fetch_async and fetch_async_get described below.
  • Only works at init time and must be called from the mod's main scope (not from a function).
  • Function only exists if Luanti server was built with cURL support.
  • DO NOT ALLOW ANY OTHER MODS TO ACCESS THE RETURNED TABLE, STORE IT IN A LOCAL VARIABLE!
• HTTPApiTable.fetch(HTTPRequest req, callback)
  • Performs given request asynchronously and calls callback upon completion
  • callback: function(HTTPRequestResult res)
  • Use this HTTP function if you are unsure, the others are for advanced use
• HTTPApiTable.fetch_async(HTTPRequest req): returns handle
  • Performs given request asynchronously and returns handle for HTTPApiTable.fetch_async_get
• HTTPApiTable.fetch_async_get(handle): returns HTTPRequestResult
  • Return response data for given asynchronous HTTP request

Storage API

• core.get_mod_storage():
  • returns reference to mod private StorageRef
  • must be called during mod load time

Misc.

• core.get_connected_players(): returns list of ObjectRefs
• core.is_player(obj): boolean, whether obj is a player
• core.player_exists(name): boolean, whether player exists (regardless of online status)
• core.is_valid_player_name(name): boolean, whether the given name could be used as a player name (regardless of whether said player exists).
• core.hud_replace_builtin(name, hud_definition)
  • Replaces definition of a builtin hud element
  • name: "breath", "health", "minimap" or "hotbar"
  • hud_definition: definition to replace builtin definition
• core.parse_relative_number(arg, relative_to): returns number or nil
  • Helper function for chat commands.
  • For parsing an optionally relative number of a chat command parameter, using the chat command tilde notation.
  • arg: String snippet containing the number; possible values:
    • "<number>": return as number
    • "~<number>": return relative_to + <number>
    • "~": return relative_to
    • Anything else will return nil
  • relative_to: Number to which the arg number might be relative to
  • Examples:
    • core.parse_relative_number("5", 10) returns 5
    • core.parse_relative_number("~5", 10) returns 15
    • core.parse_relative_number("~", 10) returns 10
• core.send_join_message(player_name)
  • This function can be overridden by mods to change the join message.
• core.send_leave_message(player_name, timed_out)
  • This function can be overridden by mods to change the leave message.
• core.hash_node_position(pos): returns a 48-bit integer
  • pos: table {x=number, y=number, z=number},
  • Gives a unique hash number for a node position (16+16+16=48bit)
• core.get_position_from_hash(hash): returns a position
  • Inverse transform of core.hash_node_position
• core.get_item_group(name, group): returns a rating
  • Get rating of a group of an item. (0 means: not in group)
• core.get_node_group(name, group): returns a rating
  • Deprecated: An alias for the former.
• core.raillike_group(name): returns a rating
  • Returns rating of the connect_to_raillike group corresponding to name
  • If name is not yet the name of a connect_to_raillike group, a new group id is created, with that name.
• core.get_content_id(name): returns an integer
  • Gets the internal content ID of name
• core.get_name_from_content_id(content_id): returns a string
  • Gets the name of the content with that content ID
• core.parse_json(string[, nullvalue, return_error]): returns something
  • Convert a string containing JSON data into the Lua equivalent
  • nullvalue: returned in place of the JSON null; defaults to nil
  • On success returns a table, a string, a number, a boolean or nullvalue
  • On failure: If return_error is not set or is false, outputs an error message and returns nil. Otherwise returns nil, err (error message).
  • Example: parse_json("[10, {\"a\":false}]"), returns {10, {a = false}}
• core.write_json(data[, styled]): returns a string or nil and an error message.
  • Convert a Lua table into a JSON string
  • styled: Outputs in a human-readable format if this is set, defaults to false.
  • Unserializable things like functions and userdata will cause an error.
  • Warning: JSON is more strict than the Lua table format.
    1. You can only use strings and positive integers of at least one as keys.
    2. You cannot mix string and integer keys. This is due to the fact that JSON has two distinct array and object values.
  • Example: write_json({10, {a = false}}), returns '[10, {"a": false}]'
• core.serialize(table): returns a string
  • Convert a table containing tables, strings, numbers, booleans and nils into string form readable by core.deserialize
  • Example: serialize({foo="bar"}), returns 'return { ["foo"] = "bar" }'
• core.deserialize(string[, safe]): returns a table
  • Convert a string returned by core.serialize into a table
  • string is loaded in an empty sandbox environment.
  • Will load functions if safe is false or omitted. Although these functions cannot directly access the global environment, they could bypass this restriction with maliciously crafted Lua bytecode if mod security is disabled.
  • This function should not be used on untrusted data, regardless of the value of safe. It is fine to serialize then deserialize user-provided data, but directly providing user input to deserialize is always unsafe.
  • Example: deserialize('return { ["foo"] = "bar" }'), returns {foo="bar"}
  • Example: deserialize('print("foo")'), returns nil (function call fails), returns error:[string "print("foo")"]:1: attempt to call global 'print' (a nil value)
• core.compress(data, method, ...): returns compressed_data
  • Compress a string of data.
  • method is a string identifying the compression method to be used.
  • Supported compression methods:
    • Deflate (zlib): "deflate"
    • Zstandard: "zstd"
  • ... indicates method-specific arguments. Currently defined arguments are:
    • Deflate: level - Compression level, 0-9 or nil.
    • Zstandard: level - Compression level. Integer or nil. Default 3. Note any supported Zstandard compression level could be used here, but these are subject to change between Zstandard versions.
• core.decompress(compressed_data, method, ...): returns data
  • Decompress a string of data using the algorithm specified by method.
  • See documentation on core.compress() for supported compression methods.
  • ... indicates method-specific arguments. Currently, no methods use this
• core.rgba(red, green, blue[, alpha]): returns a string
  • Each argument is an 8 Bit unsigned integer
  • Returns the ColorString from rgb or rgba values
  • Example: core.rgba(10, 20, 30, 40), returns "#0A141E28"
• core.encode_base64(string): returns string encoded in base64
  • Encodes a string in base64.
• core.decode_base64(string): returns string or nil on failure
  • Padding characters are only supported starting at version 5.4.0, where 5.5.0 and newer perform proper checks.
  • Decodes a string encoded in base64.
• core.is_protected(pos, name): returns boolean
  • Returning true restricts the player name from modifying (i.e. digging, placing) the node at position pos.
  • name will be "" for non-players or unknown players.
  • This function should be overridden by protection mods. It is highly recommended to grant access to players with the protection_bypass privilege.
  • Cache and call the old version of this function if the position is not protected by the mod. This will allow using multiple protection mods.
  • Example: lua local old_is_protected = core.is_protected function core.is_protected(pos, name) if mymod:position_protected_from(pos, name) then return true end return old_is_protected(pos, name) end
• core.record_protection_violation(pos, name)
  • This function calls functions registered with core.register_on_protection_violation.
• core.is_creative_enabled(name): returns boolean
  • Returning true means that Creative Mode is enabled for player name.
  • name will be "" for non-players or if the player is unknown.
  • This function should be overridden by Creative Mode-related mods to implement a per-player Creative Mode.
  • By default, this function returns true if the setting creative_mode is true and false otherwise.
• core.is_area_protected(pos1, pos2, player_name, interval)
  • Returns the position of the first node that player_name may not modify in the specified cuboid between pos1 and pos2.
  • Returns false if no protections were found.
  • Applies is_protected() to a 3D lattice of points in the defined volume. The points are spaced evenly throughout the volume and have a spacing similar to, but no larger than, interval.
  • All corners and edges of the defined volume are checked.
  • interval defaults to 4.
  • interval should be carefully chosen and maximized to avoid an excessive number of points being checked.
  • Like core.is_protected, this function may be extended or overwritten by mods to provide a faster implementation to check the cuboid for intersections.
• core.rotate_and_place(itemstack, placer, pointed_thing[, infinitestacks, orient_flags, prevent_after_place])
  • Attempt to predict the desired orientation of the facedir-capable node defined by itemstack, and place it accordingly (on-wall, on the floor, or hanging from the ceiling).
  • infinitestacks: if true, the itemstack is not changed. Otherwise the stacks are handled normally.
  • orient_flags: Optional table containing extra tweaks to the placement code:
    • invert_wall: if true, place wall-orientation on the ground and ground-orientation on the wall.
    • force_wall: if true, always place the node in wall orientation.
    • force_ceiling: if true, always place on the ceiling.
    • force_floor: if true, always place the node on the floor.
    • force_facedir: if true, forcefully reset the facedir to north when placing on the floor or ceiling.
    • The first four options are mutually-exclusive; the last in the list takes precedence over the first.
  • prevent_after_place is directly passed to core.item_place_node
  • Returns the new itemstack after placement

• core.rotate_node(itemstack, placer, pointed_thing)

  • calls rotate_and_place() with infinitestacks set according to the state of the creative mode setting, checks for "sneak" to set the invert_wall parameter and prevent_after_place set to true.

• core.calculate_knockback(player, hitter, time_from_last_punch, tool_capabilities, dir, distance, damage)

  • Returns the amount of knockback applied on the punched player.
  • Arguments are equivalent to register_on_punchplayer, except the following:
    • distance: distance between puncher and punched player
  • This function can be overridden by mods that wish to modify this behavior.
  • You may want to cache and call the old function to allow multiple mods to change knockback behavior.

• core.forceload_block(pos[, transient[, limit]])

  • forceloads the position pos.
  • returns true if area could be forceloaded
  • If transient is false or absent, the forceload will be persistent (saved between server runs). If true, the forceload will be transient (not saved between server runs).
  • limit is an optional limit on the number of blocks that can be forceloaded at once. If limit is negative, there is no limit. If it is absent, the limit is the value of the setting "max_forceloaded_blocks". If the call would put the number of blocks over the limit, the call fails.

• core.forceload_free_block(pos[, transient])

  • stops forceloading the position pos
  • If transient is false or absent, frees a persistent forceload. If true, frees a transient forceload.

• core.compare_block_status(pos, condition)

  • Checks whether the mapblock at position pos is in the wanted condition.
  • condition may be one of the following values:
    • "unknown": not in memory
    • "emerging": in the queue for loading from disk or generating
    • "loaded": in memory but inactive (no ABMs are executed)
    • "active": in memory and active
    • Other values are reserved for future functionality extensions
  • Return value, the comparison status:
    • false: Mapblock does not fulfill the wanted condition
    • true: Mapblock meets the requirement
    • nil: Unsupported condition value

• core.request_insecure_environment(): returns an environment containing insecure functions if the calling mod has been listed as trusted in the secure.trusted_mods setting or security is disabled, otherwise returns nil.

  • Only works at init time and must be called from the mod's main scope (ie: the init.lua of the mod, not from another Lua file or within a function).
  • DO NOT ALLOW ANY OTHER MODS TO ACCESS THE RETURNED ENVIRONMENT, STORE IT IN A LOCAL VARIABLE!

• core.global_exists(name)

  • Checks if a global variable has been set, without triggering a warning.

• core.register_portable_metatable(name, mt):

  • Register a metatable that should be preserved when Lua data is transferred between environments (via IPC or handle_async).
  • name is a string that identifies the metatable. It is recommended to follow the modname:name convention for this identifier.
  • mt is the metatable to register.
  • Note that the same metatable can be registered under multiple names, but multiple metatables must not be registered under the same name.
  • You must register the metatable in both the main environment and the async environment for this mechanism to work.

Global objects

• core.env: EnvRef of the server environment and world.
  • Any function in the core namespace can be called using the syntax core.env:somefunction(somearguments) instead of core.somefunction(somearguments)
  • Deprecated, but support is not to be dropped soon
• minetest: alias for the core namespace
  • Deprecated, but support is not to be dropped soon

Global tables

Registered definition tables

• core.registered_items
  • Map of registered items, indexed by name
• core.registered_nodes
  • Map of registered node definitions, indexed by name
• core.registered_craftitems
  • Map of registered craft item definitions, indexed by name
• core.registered_tools
  • Map of registered tool definitions, indexed by name
• core.registered_entities
  • Map of registered entity prototypes, indexed by name
  • Values in this table may be modified directly. Note: changes to initial properties will only affect entities spawned afterwards, as they are only read when spawning.
• core.object_refs
  • Map of object references, indexed by active object id
• core.luaentities
  • Map of Lua entities, indexed by active object id
• core.registered_abms
  • List of ABM definitions
• core.registered_lbms
  • List of LBM definitions
• core.registered_aliases
  • Map of registered aliases, indexed by name
• core.registered_ores
  • Map of registered ore definitions, indexed by the name field.
  • If name is nil, the key is the object handle returned by core.register_ore.
• core.registered_biomes
  • Map of registered biome definitions, indexed by the name field.
  • If name is nil, the key is the object handle returned by core.register_biome.
• core.registered_decorations
  • Map of registered decoration definitions, indexed by the name field.
  • If name is nil, the key is the object handle returned by core.register_decoration.
• core.registered_chatcommands
  • Map of registered chat command definitions, indexed by name
• core.registered_privileges
  • Map of registered privilege definitions, indexed by name
  • Registered privileges can be modified directly in this table.

Registered callback tables

All callbacks registered with [Global callback registration functions] are added to corresponding core.registered_* tables.

For historical reasons, the use of an -s suffix in these names is inconsistent.

• core.registered_on_chat_messages
• core.registered_on_chatcommands
• core.registered_globalsteps
• core.registered_on_punchnodes
• core.registered_on_placenodes
• core.registered_on_dignodes
• core.registered_on_generateds
• core.registered_on_newplayers
• core.registered_on_dieplayers
• core.registered_on_respawnplayers
• core.registered_on_prejoinplayers
• core.registered_on_joinplayers
• core.registered_on_leaveplayers
• core.registered_on_player_receive_fields
• core.registered_on_cheats
• core.registered_on_crafts
• core.registered_craft_predicts
• core.registered_on_item_eats
• core.registered_on_item_pickups
• core.registered_on_punchplayers
• core.registered_on_authplayers
• core.registered_on_player_inventory_actions
• core.registered_allow_player_inventory_actions
• core.registered_on_rightclickplayers
• core.registered_on_mods_loaded
• core.registered_on_shutdown
• core.registered_on_protection_violation
• core.registered_on_priv_grant
• core.registered_on_priv_revoke
• core.registered_can_bypass_userlimit
• core.registered_on_modchannel_message
• core.registered_on_liquid_transformed
• core.registered_on_mapblocks_changed

Class reference

Sorted alphabetically.

AreaStore

AreaStore is a data structure to calculate intersections of 3D cuboid volumes and points. The data field (string) may be used to store and retrieve any mod-relevant information to the specified area.

Despite its name, mods must take care of persisting AreaStore data. They may use the provided load and write functions for this.

Methods

• AreaStore(type_name)
  • Returns a new AreaStore instance
  • type_name: optional, forces the internally used API.
    • Possible values: "LibSpatial" (default).
    • When other values are specified, or SpatialIndex is not available, the custom Luanti functions are used.

• get_area(id, include_corners, include_data)

  • Returns the area information about the specified ID.
  • Returned values are either of these: lua nil -- Area not found true -- Without `include_corners` and `include_data` { min = pos, max = pos -- `include_corners == true` data = string -- `include_data == true` }

• get_areas_for_pos(pos, include_corners, include_data)

  • Returns all areas as table, indexed by the area ID.
  • Table values: see get_area.

• get_areas_in_area(corner1, corner2, accept_overlap, include_corners, include_data)

  • Returns all areas that contain all nodes inside the area specified by corner1 and corner2 (inclusive).
  • accept_overlap: if true, areas are returned that have nodes in common (intersect) with the specified area.
  • Returns the same values as get_areas_for_pos.

• insert_area(corner1, corner2, data, [id]): inserts an area into the store.

  • Returns the new area's ID, or nil if the insertion failed.
  • The (inclusive) positions corner1 and corner2 describe the area.
  • data is a string stored with the area.
  • id (optional): will be used as the internal area ID if it is a unique number between 0 and 2^32-2.

• reserve(count)

  • Requires SpatialIndex, no-op function otherwise.
  • Reserves resources for count many contained areas to improve efficiency when working with many area entries. Additional areas can still be inserted afterwards at the usual complexity.

• remove_area(id): removes the area with the given id from the store, returns success.

• set_cache_params(params): sets params for the included prefiltering cache. Calling invalidates the cache, so that its elements have to be newly generated.

  • params is a table with the following fields: lua { enabled = boolean, -- Whether to enable, default true block_radius = int, -- The radius (in nodes) of the areas the cache -- generates prefiltered lists for, minimum 16, -- default 64 limit = int, -- The cache size, minimum 20, default 1000 }

• to_string(): Experimental. Returns area store serialized as a (binary) string.

• to_file(filename): Experimental. Like to_string(), but writes the data to a file.

• from_string(str): Experimental. Deserializes string and loads it into the AreaStore. Returns success and, optionally, an error message.

• from_file(filename): Experimental. Like from_string(), but reads the data from a file.

InvRef

An InvRef is a reference to an inventory.

Methods

• is_empty(listname): return true if list is empty
• get_size(listname): get size of a list
• set_size(listname, size): set size of a list
  • If listname is not known, a new list will be created
  • Setting size to 0 deletes a list
  • returns false on error (e.g. invalid listname or size)
• get_width(listname): get width of a list
• set_width(listname, width): set width of list; currently used for crafting
  • returns false on error (e.g. invalid listname or width)
• get_stack(listname, i): get a copy of stack index i in list
• set_stack(listname, i, stack): copy stack to index i in list
• get_list(listname): returns full list (list of ItemStacks) or nil if list doesn't exist (size 0)
• set_list(listname, list): set full list (size will not change)
• get_lists(): returns table that maps listnames to inventory lists
• set_lists(lists): sets inventory lists (size will not change)
• add_item(listname, stack): add item somewhere in list, returns leftover ItemStack.
• room_for_item(listname, stack): returns true if the stack of items can be fully added to the list
• contains_item(listname, stack, [match_meta]): returns true if the stack of items can be fully taken from the list. If match_meta is false, only the items' names are compared (default: false).
• remove_item(listname, stack): take as many items as specified from the list, returns the items that were actually removed (as an ItemStack) -- note that any item metadata is ignored, so attempting to remove a specific unique item this way will likely remove the wrong one -- to do that use set_stack with an empty ItemStack.
• get_location(): returns a location compatible to core.get_inventory(location).
  • returns {type="undefined"} in case location is not known

Callbacks

Detached & nodemeta inventories provide the following callbacks for move actions:

Before

The allow_* callbacks return how many items can be moved.

• allow_move/allow_metadata_inventory_move: Moving items in the inventory
• allow_take/allow_metadata_inventory_take: Taking items from the inventory
• allow_put/allow_metadata_inventory_put: Putting items to the inventory

After

The on_* callbacks are called after the items have been placed in the inventories.

• on_move/on_metadata_inventory_move: Moving items in the inventory
• on_take/on_metadata_inventory_take: Taking items from the inventory
• on_put/on_metadata_inventory_put: Putting items to the inventory

Swapping

When a player tries to put an item to a place where another item is, the items are swapped. This means that all callbacks will be called twice (once for each action).

ItemStack

An ItemStack is a stack of items.

It can be created via ItemStack(x), where x is an ItemStack, an itemstring, a table or nil.

Methods

• is_empty(): returns true if stack is empty.
• get_name(): returns item name (e.g. "default:stone").
• set_name(item_name): returns a boolean indicating whether the item was cleared.
• get_count(): Returns number of items on the stack.
• set_count(count): returns a boolean indicating whether the item was cleared
  • count: number, unsigned 16 bit integer
• get_wear(): returns tool wear (0-65535), 0 for non-tools.
• set_wear(wear): returns boolean indicating whether item was cleared
  • wear: number, unsigned 16 bit integer
• get_meta(): returns ItemStackMetaRef. See section for more details
• get_metadata(): Deprecated. Returns metadata (a string attached to an item stack).
  • If you need to access this to maintain backwards compatibility, use stack:get_meta():get_string("") instead.
• set_metadata(metadata): Deprecated. Returns true.
  • If you need to set this to maintain backwards compatibility, use stack:get_meta():set_string("", metadata) instead.
• get_description(): returns the description shown in inventory list tooltips.
  • The engine uses this when showing item descriptions in tooltips.
  • Fields for finding the description, in order:
    • description in item metadata (See [Item Metadata].)
    • description in item definition
    • item name
• get_short_description(): returns the short description or nil.
  • Unlike the description, this does not include new lines.
  • Fields for finding the short description, in order:
    • short_description in item metadata (See [Item Metadata].)
    • short_description in item definition
    • first line of the description (From item meta or def, see get_description().)
    • Returns nil if none of the above are set
• clear(): removes all items from the stack, making it empty.
• replace(item): replace the contents of this stack.
  • item can also be an itemstring or table.
• to_string(): returns the stack in itemstring form.
• to_table(): returns the stack in Lua table form.
• get_stack_max(): returns the maximum size of the stack (depends on the item).
• get_free_space(): returns get_stack_max() - get_count().
• is_known(): returns true if the item name refers to a defined item type.
• get_definition(): returns the item definition table.
• get_tool_capabilities(): returns the digging properties of the item, or those of the hand if none are defined for this item type
• add_wear(amount)
  • Increases wear by amount if the item is a tool, otherwise does nothing
  • Valid amount range is [0,65536]
  • amount: number, integer
• add_wear_by_uses(max_uses)
  • Increases wear in such a way that, if only this function is called, the item breaks after max_uses times
  • Valid max_uses range is [0,65536]
  • Does nothing if item is not a tool or if max_uses is 0
• get_wear_bar_params(): returns the wear bar parameters of the item, or nil if none are defined for this item type or in the stack's meta
• add_item(item): returns leftover ItemStack
  • Put some item or stack onto this stack
• item_fits(item): returns true if item or stack can be fully added to this one.
• take_item(n): returns taken ItemStack
  • Take (and remove) up to n items from this stack
  • n: number, default: 1
• peek_item(n): returns taken ItemStack
  • Copy (don't remove) up to n items from this stack
  • n: number, default: 1
• equals(other):
  • returns true if this stack is identical to other.
  • Note: stack1:to_string() == stack2:to_string() is not reliable, as stack metadata can be serialized in arbitrary order.
  • Note: if other is an itemstring or table representation of an ItemStack, this will always return false, even if it is "equivalent".

Operators

• stack1 == stack2:
  • Returns whether stack1 and stack2 are identical.
  • Note: stack1:to_string() == stack2:to_string() is not reliable, as stack metadata can be serialized in arbitrary order.
  • Note: if stack2 is an itemstring or table representation of an ItemStack, this will always return false, even if it is "equivalent".

ItemStackMetaRef

ItemStack metadata: reference extra data and functionality stored in a stack. Can be obtained via item:get_meta().

Methods

• All methods in MetaDataRef
• set_tool_capabilities([tool_capabilities])
  • Overrides the item's tool capabilities
  • A nil value will clear the override data and restore the original behavior.
• set_wear_bar_params([wear_bar_params])
  • Overrides the item's wear bar parameters (see "Wear Bar Color" section)
  • A nil value will clear the override data and restore the original behavior.

MetaDataRef

Base class used by [StorageRef], [NodeMetaRef], [ItemStackMetaRef], and [PlayerMetaRef].

Note: If a metadata value is in the format ${k}, an attempt to get the value will return the value associated with key k. There is a low recursion limit. This behavior is deprecated and will be removed in a future version. Usage of the ${k} syntax in formspecs is not deprecated.

Methods

• contains(key): Returns true if key present, otherwise false.
  • Returns nil when the MetaData is inexistent.
• get(key): Returns nil if key not present, else the stored string.
• set_string(key, value): Value of "" will delete the key.
• get_string(key): Returns "" if key not present.
• set_int(key, value)
  • The range for the value is system-dependent (usually 32 bits). The value will be converted into a string when stored.
• get_int(key): Returns 0 if key not present.
• set_float(key, value)
  • The range for the value is system-dependent (usually 32 bits). The value will be converted into a string when stored.
• get_float(key): Returns 0 if key not present.
• get_keys(): returns a list of all keys in the metadata.
• to_table():
  • Returns a metadata table (see below) or nil on failure.
• from_table(data)
  • Imports metadata from a metadata table
  • If data is a metadata table (see below), the metadata it represents will replace all metadata of this MetaDataRef object
  • Any non-table value for data will clear all metadata
  • Item table values the inventory field may also be itemstrings
  • Returns true on success
• equals(other)
  • returns true if this metadata has the same key-value pairs as other

Metadata tables

Metadata tables represent MetaDataRef in a Lua table form (see from_table/to_table).

A metadata table is a table that has the following keys:

• fields: key-value storage of metadata fields
  • all values are stored as strings
  • numbers must be converted to strings first
• inventory (for NodeMetaRef only): A node inventory in table form
  • inventory table keys are inventory list names
  • inventory table values are item tables
  • item table keys are slot IDs (starting with 1)
  • item table values are ItemStacks

Example:

metadata_table = {
    -- metadata fields (key/value store)
    fields = {
        infotext = "Container",
        another_key = "Another Value",
    },

    -- inventory data (for nodes)
    inventory = {
        -- inventory list "main" with 4 slots
        main = {
            -- list of all item slots
            [1] = "example:dirt",
            [2] = "example:stone 25",
            [3] = "", -- empty slot
            [4] = "example:pickaxe",
        },
        -- inventory list "hidden" with 1 slot
        hidden = {
            [1] = "example:diamond",
        },
    },
}

ModChannel

An interface to use mod channels on client and server

Methods

• leave(): leave the mod channel.
  • Server leaves channel channel_name.
  • No more incoming or outgoing messages can be sent to this channel from server mods.
  • This invalidate all future object usage.
  • Ensure you set mod_channel to nil after that to free Lua resources.
• is_writeable(): returns true if channel is writeable and mod can send over it.
• send_all(message): Send message though the mod channel.
  • If mod channel is not writeable or invalid, message will be dropped.
  • Message size is limited to 65535 characters by protocol.

NodeMetaRef

Node metadata: reference extra data and functionality stored in a node. Can be obtained via core.get_meta(pos).

Methods

• All methods in MetaDataRef
• get_inventory(): returns InvRef
• mark_as_private(name or {name1, name2, ...}): Mark specific vars as private This will prevent them from being sent to the client. Note that the "private" status will only be remembered if an associated key-value pair exists, meaning it's best to call this when initializing all other meta (e.g. on_construct).

NodeTimerRef

Node Timers: a high resolution persistent per-node timer. Can be gotten via core.get_node_timer(pos).

Methods

• set(timeout,elapsed)
  • set a timer's state
  • timeout is in seconds, and supports fractional values (0.1 etc)
  • elapsed is in seconds, and supports fractional values (0.1 etc)
  • will trigger the node's on_timer function after (timeout - elapsed) seconds.
• start(timeout)
  • start a timer
  • equivalent to set(timeout,0)
• stop()
  • stops the timer
• get_timeout(): returns current timeout in seconds
  • if timeout equals 0, timer is inactive
• get_elapsed(): returns current elapsed time in seconds
  • the node's on_timer function will be called after (timeout - elapsed) seconds.
• is_started(): returns boolean state of timer
  • returns true if timer is started, otherwise false

ObjectRef

Moving things in the game are generally these. This is basically a reference to a C++ ServerActiveObject.

Advice on handling ObjectRefs

When you receive an ObjectRef as a callback argument or from another API function, it is possible to store the reference somewhere and keep it around. It will keep functioning until the object is unloaded or removed.

However, doing this is NOT recommended - ObjectRefs should be "let go" of as soon as control is returned from Lua back to the engine.

Doing so is much less error-prone and you will never need to wonder if the object you are working with still exists.

If this is not feasible, you can test whether an ObjectRef is still valid via object:is_valid().

Getters may be called for invalid objects and will return nothing then. All other methods should not be called on invalid objects.

Attachments

It is possible to attach objects to other objects (set_attach method).

When an object is attached, it is positioned relative to the parent's position and rotation. get_pos and get_rotation will always return the parent's values and changes via their setter counterparts are ignored.

To change position or rotation call set_attach again with the new values.

Note: Just like model dimensions, the relative position in set_attach must be multiplied by 10 compared to world positions.

It is also possible to attach to a bone of the parent object. In that case the child will follow movement and rotation of that bone.

Methods

• is_valid(): returns whether the object is valid.
  • See "Advice on handling ObjectRefs" above.
• get_pos(): returns position as vector {x=num, y=num, z=num}
• set_pos(pos):
  • Sets the position of the object.
  • No-op if object is attached.
  • pos is a vector {x=num, y=num, z=num}
• add_pos(pos):
  • Changes position by adding to the current position.
  • No-op if object is attached.
  • pos is a vector {x=num, y=num, z=num}.
  • In comparison to using set_pos, add_pos will avoid synchronization problems.
• get_velocity(): returns the velocity, a vector.
• add_velocity(vel)
  • Changes velocity by adding to the current velocity.
  • vel is a vector, e.g. {x=0.0, y=2.3, z=1.0}
  • In comparison to using get_velocity, adding the velocity and then using set_velocity, add_velocity is supposed to avoid synchronization problems. Additionally, players also do not support set_velocity.
  • If object is a player:
    • Does not apply during free_move.
    • Note that since the player speed is normalized at each move step, increasing e.g. Y velocity beyond what would usually be achieved (see: physics overrides) will cause existing X/Z velocity to be reduced.
    • Example: add_velocity({x=0, y=6.5, z=0}) is equivalent to pressing the jump key (assuming default settings)
• move_to(pos, continuous=false)
  • Does an interpolated move for Lua entities for visually smooth transitions.
  • If continuous is true, the Lua entity will not be moved to the current position before starting the interpolated move.
  • For players this does the same as set_pos,continuous is ignored.
  • no-op if object is attached
• punch(puncher, time_from_last_punch, tool_capabilities, dir)
  • punches the object, triggering all consequences a normal punch would have
  • puncher: another ObjectRef which punched the object or nil
  • dir: direction vector of punch
  • Other arguments: See on_punch for entities
  • Arguments time_from_last_punch, tool_capabilities, and dir will be replaced with a default value when the caller sets them to nil.
• right_click(clicker):
  • simulates using the 'place/use' key on the object
  • triggers all consequences as if a real player had done this
  • clicker is another ObjectRef which has clicked
  • note: this is called right_click for historical reasons only
• get_hp(): returns number of health points
• set_hp(hp, reason): set number of health points
  • See reason in register_on_player_hpchange
  • Is limited to the range of 0 ... 65535 (2^16 - 1)
  • For players: HP are also limited by hp_max specified in object properties
• get_inventory(): returns an InvRef for players, otherwise returns nil
• get_wield_list(): returns the name of the inventory list the wielded item is in.
• get_wield_index(): returns the wield list index of the wielded item (starting with 1)
• get_wielded_item(): returns a copy of the wielded item as an ItemStack
• set_wielded_item(item): replaces the wielded item, returns true if successful.
• get_armor_groups():
  • returns a table with all of the object's armor group ratings
  • syntax: the table keys are the armor group names, the table values are the corresponding group ratings
  • see section 'ObjectRef armor groups' for details
• set_armor_groups({group1=rating, group2=rating, ...})
  • sets the object's full list of armor groups
  • same table syntax as for get_armor_groups
  • note: all armor groups not in the table will be removed
• set_animation(frame_range, frame_speed, frame_blend, frame_loop)
  • Sets the object animation parameters and (re)starts the animation
  • Animations only work with a "mesh" visual
  • frame_range: Beginning and end frame (as specified in the mesh file).
    • Syntax: {x=start_frame, y=end_frame}
    • Animation interpolates towards the end frame but stops when it is reached
    • If looped, there is no interpolation back to the start frame
    • If looped, the model should look identical at start and end
    • default: {x=1.0, y=1.0}
  • frame_speed: How fast the animation plays, in frames per second (number)
    • default: 15.0
  • frame_blend: number, default: 0.0
  • frame_loop: If true, animation will loop. If false, it will play once
    • default: true
• get_animation(): returns current animation parameters set by set_animation:
  • frame_range, frame_speed, frame_blend, frame_loop.
• set_animation_frame_speed(frame_speed)
  • Sets the frame speed of the object's animation
  • Unlike set_animation, this will not restart the animation
  • frame_speed: See set_animation
• set_attach(parent[, bone, position, rotation, forced_visible])
  • Attaches object to parent
  • See 'Attachments' section for details
  • parent: ObjectRef to attach to
  • bone: Bone to attach to. Default is "" (the root bone)
  • position: relative position, default {x=0, y=0, z=0}
  • rotation: relative rotation in degrees, default {x=0, y=0, z=0}
  • forced_visible: Boolean to control whether the attached entity should appear in first person, default false.
  • This command may fail silently (do nothing) when it would result in circular attachments.
• get_attach():
  • returns current attachment parameters or nil if it isn't attached
  • If attached, returns parent, bone, position, rotation, forced_visible
• get_children(): returns a list of ObjectRefs that are attached to the object.
• set_detach(): Detaches object. No-op if object was not attached.
• set_bone_position([bone, position, rotation])
  • Sets absolute bone overrides, e.g. it is equivalent to lua obj:set_bone_override(bone, { position = {vec = position, absolute = true}, rotation = {vec = rotation:apply(math.rad), absolute = true} })
  • Note: Rotation is in degrees, not radians.
  • Deprecated: Use set_bone_override instead.
• get_bone_position(bone): returns the previously set position and rotation of the bone
  • Shorthand for get_bone_override(bone).position.vec, get_bone_override(bone).rotation.vec:apply(math.deg).
  • Note: Returned rotation is in degrees, not radians.
  • Deprecated: Use get_bone_override instead.
• set_bone_override(bone, override)
  • bone: string
  • override: { position = property, rotation = property, scale = property } or nil
  • override = nil (including omission) is shorthand for override = {} which clears the override
  • Each property is a table of the form { vec = vector, interpolation = 0, absolute = false } or nil
    • vec is in the same coordinate system as the model, and in radians for rotation. It defaults to vector.zero() for translation and rotation and vector.new(1, 1, 1) for scale.
    • interpolation: The old and new overrides are interpolated over this timeframe (in seconds).
    • absolute: If set to false (which is the default), the override will be relative to the animated property:
      • Translation in the case of position;
      • Composition in the case of rotation;
      • Per-axis multiplication in the case of scale
  • property = nil is equivalent to no override on that property
  • Note: Unlike set_bone_position, the rotation is in radians, not degrees.
  • Compatibility note: Clients prior to 5.9.0 only support absolute position and rotation. All values are treated as absolute and are set immediately (no interpolation).
• get_bone_override(bone): returns override in the above format
  • Note: Unlike get_bone_position, the returned rotation is in radians, not degrees.
• get_bone_overrides(): returns all bone overrides as table {[bonename] = override, ...}
• set_properties(object property table)
• get_properties(): returns a table of all object properties
• set_observers(observers): sets observers (players this object is sent to)
  • If observers is nil, the object's observers are "unmanaged": The object is sent to all players as governed by server settings. This is the default.
  • observers is a "set" of player names: {name1 = true, name2 = true, ...}
    • A set is a table where the keys are the elements of the set (in this case, valid player names) and the values are all true.
  • Attachments: The effective observers of an object are made up of all players who can observe the object and are also effective observers of its parent object (if there is one).
  • Players are automatically added to their own observer sets. Players must effectively observe themselves.
  • Object activation and deactivation are unaffected by observability.
  • Attached sounds do not work correctly and thus should not be used on objects with managed observers yet.
• get_observers():
  • throws an error if the object is invalid
  • returns nil if the observers are unmanaged
  • returns a table with all observer names as keys and true values (a "set") otherwise
• get_effective_observers():
  • Like get_observers(), but returns the "effective" observers, taking into account attachments
  • Time complexity: O(nm)
    • n: number of observers of the involved entities
    • m: number of ancestors along the attachment chain
• is_player(): returns true for players, false otherwise
• get_nametag_attributes()
  • returns a table with the attributes of the nametag of an object
  • a nametag is a HUD text rendered above the object
  • lua { text = "", color = {a=0..255, r=0..255, g=0..255, b=0..255}, bgcolor = {a=0..255, r=0..255, g=0..255, b=0..255}, }
• set_nametag_attributes(attributes)
  • sets the attributes of the nametag of an object
  • attributes: lua { text = "My Nametag", color = ColorSpec, -- ^ Text color bgcolor = ColorSpec or false, -- ^ Sets background color of nametag -- `false` will cause the background to be set automatically based on user settings -- Default: false }

Lua entity only (no-op for other objects)

• remove(): remove object
  • The object is removed after returning from Lua. However the ObjectRef itself instantly becomes unusable with all further method calls having no effect and returning nil.
• set_velocity(vel)
  • Sets the velocity
  • vel is a vector, e.g. {x=0.0, y=2.3, z=1.0}
• set_acceleration(acc)
  • Sets the acceleration
  • acc is a vector
• get_acceleration(): returns the acceleration, a vector
• set_rotation(rot)
  • Sets the rotation
  • rot is a vector (radians). X is pitch (elevation), Y is yaw (heading) and Z is roll (bank).
  • Does not reset rotation incurred through automatic_rotate. Remove & re-add your objects to force a certain rotation.
• get_rotation(): returns the rotation, a vector (radians)
• set_yaw(yaw): sets the yaw in radians (heading).
• get_yaw(): returns number in radians
• set_texture_mod(mod)
  • Set a texture modifier to the base texture, for sprites and meshes.
  • When calling set_texture_mod again, the previous one is discarded.
  • mod the texture modifier. See [Texture modifiers].
• get_texture_mod() returns current texture modifier
• set_sprite(start_frame, num_frames, framelength, select_x_by_camera)
  • Specifies and starts a sprite animation
  • Only used by sprite and upright_sprite visuals
  • Animations iterate along the frame y position.
  • start_frame: {x=column number, y=row number}, the coordinate of the first frame, default: {x=0, y=0}
  • num_frames: Total frames in the texture, default: 1
  • framelength: Time per animated frame in seconds, default: 0.2
  • select_x_by_camera: Only for visual = sprite. Changes the frame x position according to the view direction. default: false.
    • First column: subject facing the camera
    • Second column: subject looking to the left
    • Third column: subject backing the camera
    • Fourth column: subject looking to the right
    • Fifth column: subject viewed from above
    • Sixth column: subject viewed from below
• get_luaentity():
  • Returns the object's associated luaentity table, if there is one
  • Otherwise returns nil (e.g. for players)
• get_entity_name():
  • Deprecated: Will be removed in a future version, use :get_luaentity().name instead.

Player only (no-op for other objects)

• get_player_name(): Returns player name or "" if is not a player
• get_player_velocity(): DEPRECATED, use get_velocity() instead. table {x, y, z} representing the player's instantaneous velocity in nodes/s
• add_player_velocity(vel): DEPRECATED, use add_velocity(vel) instead.
• get_look_dir(): get camera direction as a unit vector
• get_look_vertical(): pitch in radians
  • Angle ranges between -pi/2 and pi/2, which are straight up and down respectively.
• get_look_horizontal(): yaw in radians
  • Angle is counter-clockwise from the +z direction.
• set_look_vertical(radians): sets look pitch
  • radians: Angle from looking forward, where positive is downwards.
• set_look_horizontal(radians): sets look yaw
  • radians: Angle from the +z direction, where positive is counter-clockwise.
• get_look_pitch(): pitch in radians - Deprecated as broken. Use get_look_vertical.
  • Angle ranges between -pi/2 and pi/2, which are straight down and up respectively.
• get_look_yaw(): yaw in radians - Deprecated as broken. Use get_look_horizontal.
  • Angle is counter-clockwise from the +x direction.
• set_look_pitch(radians): sets look pitch - Deprecated. Use set_look_vertical.
• set_look_yaw(radians): sets look yaw - Deprecated. Use set_look_horizontal.
• get_breath(): returns player's breath
• set_breath(value): sets player's breath
  • values:
    • 0: player is drowning
    • max: bubbles bar is not shown
    • See [Object properties] for more information
  • Is limited to range 0 ... 65535 (2^16 - 1)
• set_fov(fov, is_multiplier, transition_time): Sets player's FOV
  • fov: Field of View (FOV) value.
  • is_multiplier: Set to true if the FOV value is a multiplier. Defaults to false.
  • transition_time: If defined, enables smooth FOV transition. Interpreted as the time (in seconds) to reach target FOV. If set to 0, FOV change is instantaneous. Defaults to 0.
  • Set fov to 0 to clear FOV override.
• get_fov(): Returns the following:
  • Server-sent FOV value. Returns 0 if an FOV override doesn't exist.
  • Boolean indicating whether the FOV value is a multiplier.
  • Time (in seconds) taken for the FOV transition. Set by set_fov.
• set_attribute(attribute, value): DEPRECATED, use get_meta() instead
  • Sets an extra attribute with value on player.
  • value must be a string, or a number which will be converted to a string.
  • If value is nil, remove attribute from player.
• get_attribute(attribute): DEPRECATED, use get_meta() instead
  • Returns value (a string) for extra attribute.
  • Returns nil if no attribute found.
• get_meta(): Returns metadata associated with the player (a PlayerMetaRef).
• set_inventory_formspec(formspec)
  • Redefine player's inventory form
  • Should usually be called in on_joinplayer
  • If formspec is "", the player's inventory is disabled.
• get_inventory_formspec(): returns a formspec string
• set_formspec_prepend(formspec):
  • the formspec string will be added to every formspec shown to the user, except for those with a no_prepend[] tag.
  • This should be used to set style elements such as background[] and bgcolor[], any non-style elements (eg: label) may result in weird behavior.
  • Only affects formspecs shown after this is called.
• get_formspec_prepend(): returns a formspec string.
• get_player_control(): returns table with player input
  • The table contains the following boolean fields representing the pressed keys: up, down, left, right, jump, aux1, sneak, dig, place, LMB, RMB and zoom.
  • The fields LMB and RMB are equal to dig and place respectively, and exist only to preserve backwards compatibility.
  • The table also contains the fields movement_x and movement_y.
    • They represent the movement of the player. Values are numbers in the range [-1.0,+1.0].
    • They take both keyboard and joystick input into account.
    • You should prefer them over up, down, left and right to support different input methods correctly.
  • Returns an empty table {} if the object is not a player.
• get_player_control_bits(): returns integer with bit packed player pressed keys.
  • Bits:
    • 0 - up
    • 1 - down
    • 2 - left
    • 3 - right
    • 4 - jump
    • 5 - aux1
    • 6 - sneak
    • 7 - dig
    • 8 - place
    • 9 - zoom
  • Returns 0 (no bits set) if the object is not a player.

• set_physics_override(override_table)

  • Overrides the physics attributes of the player
  • override_table is a table with the following fields:
    • speed: multiplier to all movement speed (speed_*) and acceleration (acceleration_*) values (default: 1)
    • speed_walk: multiplier to default walk speed value (default: 1)
      • Note: The actual walk speed is the product of speed and speed_walk
    • speed_climb: multiplier to default climb speed value (default: 1)
      • Note: The actual climb speed is the product of speed and speed_climb
    • speed_crouch: multiplier to default sneak speed value (default: 1)
      • Note: The actual sneak speed is the product of speed and speed_crouch
    • speed_fast: multiplier to default speed value in Fast Mode (default: 1)
      • Note: The actual fast speed is the product of speed and speed_fast
    • jump: multiplier to default jump value (default: 1)
    • gravity: multiplier to default gravity value (default: 1)
    • liquid_fluidity: multiplier to liquid movement resistance value (for nodes with liquid_move_physics); the higher this value, the lower the resistance to movement. At math.huge, the resistance is zero and you can move through any liquid like air. (default: 1)
      • Warning: Values below 1 are currently unsupported.
    • liquid_fluidity_smooth: multiplier to default maximum liquid resistance value (for nodes with liquid_move_physics); controls deceleration when entering node at high speed. At higher values you come to a halt more quickly (default: 1)
    • liquid_sink: multiplier to default liquid sinking speed value; (for nodes with liquid_move_physics) (default: 1)
    • acceleration_default: multiplier to horizontal and vertical acceleration on ground or when climbing (default: 1)
      • Note: The actual acceleration is the product of speed and acceleration_default
    • acceleration_air: multiplier to acceleration when jumping or falling (default: 1)
      • Note: The actual acceleration is the product of speed and acceleration_air
    • acceleration_fast: multiplier to acceleration in Fast Mode (default: 1)
      • Note: The actual acceleration is the product of speed and acceleration_fast
    • sneak: whether player can sneak (default: true)
    • sneak_glitch: whether player can use the new move code replications of the old sneak side-effects: sneak ladders and 2 node sneak jump (default: false)
    • new_move: use new move/sneak code. When false the exact old code is used for the specific old sneak behavior (default: true)
  • Note: All numeric fields above modify a corresponding movement_* setting.
  • For games, we recommend for simpler code to first modify the movement_* settings (e.g. via the game's minetest.conf) to set a global base value for all players and only use set_physics_override when you need to change from the base value on a per-player basis
  • Note: Some of the fields don't exist in old API versions, see feature physics_overrides_v2.

• get_physics_override(): returns the table given to set_physics_override

• hud_add(hud definition): add a HUD element described by HUD def, returns ID number on success

• hud_remove(id): remove the HUD element of the specified id

• hud_change(id, stat, value): change a value of a previously added HUD element.

  • stat supports the same keys as in the hud definition table except for "type" (or the deprecated "hud_elem_type").

• hud_get(id): gets the HUD element definition structure of the specified ID

• hud_get_all():

  • Returns a table in the form { [id] = HUD definition, [id] = ... }.
  • A mod should keep track of its introduced IDs and only use this to access foreign elements.
  • It is discouraged to change foreign HUD elements.

• hud_set_flags(flags): sets specified HUD flags of player.

  • flags: A table with the following fields set to boolean values
    • hotbar
    • healthbar
    • crosshair
    • wielditem
    • breathbar
    • minimap: Modifies the client's permission to view the minimap. The client may locally elect to not view the minimap.
    • minimap_radar: is only usable when minimap is true
    • basic_debug: Allow showing basic debug info that might give a gameplay advantage. This includes map seed, player position, look direction, the pointed node and block bounds. Does not affect players with the debug privilege.
    • chat: Modifies the client's permission to view chat on the HUD. The client may locally elect to not view chat. Does not affect the console.
  • If a flag equals nil, the flag is not modified

• hud_get_flags(): returns a table of player HUD flags with boolean values.

  • See hud_set_flags for a list of flags that can be toggled.

• hud_set_hotbar_itemcount(count): sets number of items in builtin hotbar

  • count: number of items, must be between 1 and 32
  • If count exceeds the "main" list size, the list size will be used instead.

• hud_get_hotbar_itemcount(): returns number of visible items

  • This value is also clamped by the "main" list size.

• hud_set_hotbar_image(texturename)

  • sets background image for hotbar

• hud_get_hotbar_image(): returns texturename

• hud_set_hotbar_selected_image(texturename)

  • sets image for selected item of hotbar

• hud_get_hotbar_selected_image(): returns texturename

• set_minimap_modes({mode, mode, ...}, selected_mode)

  • Overrides the available minimap modes (and toggle order), and changes the selected mode.
  • mode is a table consisting of up to four fields:
    • type: Available type:
      • off: Minimap off
      • surface: Minimap in surface mode
      • radar: Minimap in radar mode
      • texture: Texture to be displayed instead of terrain map (texture is centered around 0,0 and can be scaled). Texture size is limited to 512 x 512 pixel.
    • label: Optional label to display on minimap mode toggle The translation must be handled within the mod.
    • size: Sidelength or diameter, in number of nodes, of the terrain displayed in minimap
    • texture: Only for texture type, name of the texture to display
    • scale: Only for texture type, scale of the texture map in nodes per pixel (for example a scale of 2 means each pixel represents a 2x2 nodes square)
  • selected_mode is the mode index to be selected after modes have been changed (0 is the first mode).

• set_sky(sky_parameters)

  • The presence of the function set_sun, set_moon or set_stars indicates whether set_sky accepts this format. Check the legacy format otherwise.
  • Passing no arguments resets the sky to its default values.
  • sky_parameters is a table with the following optional fields:
    • base_color: ColorSpec, meaning depends on type (default: #ffffff)
    • body_orbit_tilt: Float, rotation angle of sun/moon orbit in degrees. By default, orbit is controlled by a client-side setting, and this field is not set. After a value is assigned, it can only be changed to another float value. Valid range -60.0,60.0
    • type: Available types:
      • "regular": Uses 0 textures, base_color ignored
      • "skybox": Uses 6 textures, base_color used as fog.
      • "plain": Uses 0 textures, base_color used as both fog and sky. (default: "regular")
    • textures: A table containing up to six textures in the following order: Y+ (top), Y- (bottom), X+ (east), X- (west), Z- (south), Z+ (north). The top and bottom textures are oriented in-line with the east (X+) face (the top edge of the bottom texture and the bottom edge of the top texture touch the east face). Some top and bottom textures expect to be aligned with the north face and will need to be rotated by -90 and 90 degrees, respectively, to fit the eastward orientation.
    • clouds: Boolean for whether clouds appear. (default: true)
    • sky_color: A table used in "regular" type only, containing the following values (alpha is ignored):
      • day_sky: ColorSpec, for the top half of the sky during the day. (default: #61b5f5)
      • day_horizon: ColorSpec, for the bottom half of the sky during the day. (default: #90d3f6)
      • dawn_sky: ColorSpec, for the top half of the sky during dawn/sunset. (default: #b4bafa) The resulting sky color will be a darkened version of the ColorSpec. Warning: The darkening of the ColorSpec is subject to change.
      • dawn_horizon: ColorSpec, for the bottom half of the sky during dawn/sunset. (default: #bac1f0) The resulting sky color will be a darkened version of the ColorSpec. Warning: The darkening of the ColorSpec is subject to change.
      • night_sky: ColorSpec, for the top half of the sky during the night. (default: #006bff) The resulting sky color will be a dark version of the ColorSpec. Warning: The darkening of the ColorSpec is subject to change.
      • night_horizon: ColorSpec, for the bottom half of the sky during the night. (default: #4090ff) The resulting sky color will be a dark version of the ColorSpec. Warning: The darkening of the ColorSpec is subject to change.
      • indoors: ColorSpec, for when you're either indoors or underground. (default: #646464)
      • fog_sun_tint: ColorSpec, changes the fog tinting for the sun at sunrise and sunset. (default: #f47d1d)
      • fog_moon_tint: ColorSpec, changes the fog tinting for the moon at sunrise and sunset. (default: #7f99cc)
      • fog_tint_type: string, changes which mode the directional fog abides by, "custom" uses sun_tint and moon_tint, while "default" uses the classic Luanti sun and moon tinting. Will use tonemaps, if set to "default". (default: "default")
    • fog: A table with following optional fields:
      • fog_distance: integer, set an upper bound for the client's viewing_range. Any value >= 0 sets the desired upper bound for viewing_range, disables range_all and prevents disabling fog (F3 key by default). Any value < 0 resets the behavior to being client-controlled. (default: -1)
      • fog_start: float, override the client's fog_start. Fraction of the visible distance at which fog starts to be rendered. Any value between [0.0, 0.99] set the fog_start as a fraction of the viewing_range. Any value < 0, resets the behavior to being client-controlled. (default: -1)
      • fog_color: ColorSpec, override the color of the fog. Unlike base_color above this will apply regardless of the skybox type. (default: "#00000000", which means no override)

• set_sky(base_color, type, {texture names}, clouds)

  • Deprecated. Use set_sky(sky_parameters)
  • base_color: ColorSpec, defaults to white
  • type: Available types:
    • "regular": Uses 0 textures, bgcolor ignored
    • "skybox": Uses 6 textures, bgcolor used
    • "plain": Uses 0 textures, bgcolor used
  • clouds: Boolean for whether clouds appear in front of "skybox" or "plain" custom skyboxes (default: true)

• get_sky(as_table):

  • as_table: boolean that determines whether the deprecated version of this function is being used.
    • true returns a table containing sky parameters as defined in set_sky(sky_parameters).
    • Deprecated: false or nil returns base_color, type, table of textures, clouds.

• get_sky_color():

  • Deprecated: Use get_sky(as_table) instead.
  • returns a table with the sky_color parameters as in set_sky.

• set_sun(sun_parameters):

  • Passing no arguments resets the sun to its default values.
  • sun_parameters is a table with the following optional fields:
    • visible: Boolean for whether the sun is visible. (default: true)
    • texture: A regular texture for the sun. Setting to "" will re-enable the mesh sun. (default: "sun.png", if it exists) The texture appears non-rotated at sunrise and rotated 180 degrees (upside down) at sunset.
    • tonemap: A 512x1 texture containing the tonemap for the sun (default: "sun_tonemap.png")
    • sunrise: A regular texture for the sunrise texture. (default: "sunrisebg.png")
    • sunrise_visible: Boolean for whether the sunrise texture is visible. (default: true)
    • scale: Float controlling the overall size of the sun. (default: 1) Note: For legacy reasons, the sun is bigger than the moon by a factor of about 1.57 for equal scale values.

• get_sun(): returns a table with the current sun parameters as in set_sun.

• set_moon(moon_parameters):

  • Passing no arguments resets the moon to its default values.
  • moon_parameters is a table with the following optional fields:
    • visible: Boolean for whether the moon is visible. (default: true)
    • texture: A regular texture for the moon. Setting to "" will re-enable the mesh moon. (default: "moon.png", if it exists) The texture appears non-rotated at sunrise / moonset and rotated 180 degrees (upside down) at sunset / moonrise. Note: Relative to the sun, the moon texture is hence rotated by 180°. You can use the ^[transformR180 texture modifier to achieve the same orientation.
    • tonemap: A 512x1 texture containing the tonemap for the moon (default: "moon_tonemap.png")
    • scale: Float controlling the overall size of the moon (default: 1) Note: For legacy reasons, the sun is bigger than the moon by a factor of about 1.57 for equal scale values.

• get_moon(): returns a table with the current moon parameters as in set_moon.

• set_stars(star_parameters):

  • Passing no arguments resets stars to their default values.
  • star_parameters is a table with the following optional fields:
    • visible: Boolean for whether the stars are visible. (default: true)
    • day_opacity: Float for maximum opacity of stars at day. No effect if visible is false. (default: 0.0; maximum: 1.0; minimum: 0.0)
    • count: Integer number to set the number of stars in the skybox. Only applies to "skybox" and "regular" sky types. (default: 1000)
    • star_color: ColorSpec, sets the colors of the stars, alpha channel is used to set overall star brightness. (default: #ebebff69)
    • scale: Float controlling the overall size of the stars (default: 1)

• get_stars(): returns a table with the current stars parameters as in set_stars.

• set_clouds(cloud_parameters): set cloud parameters

  • Passing no arguments resets clouds to their default values.
  • cloud_parameters is a table with the following optional fields:
    • density: from 0 (no clouds) to 1 (full clouds) (default 0.4)
    • color: basic cloud color with alpha channel, ColorSpec (default #fff0f0e5).
    • ambient: cloud color lower bound, use for a "glow at night" effect. ColorSpec (alpha ignored, default #000000)
    • height: cloud height, i.e. y of cloud base (default per conf, usually 120)
    • thickness: cloud thickness in nodes (default 16). if set to zero the clouds are rendered flat.
    • speed: 2D cloud speed + direction in nodes per second (default {x=0, z=-2}).
    • shadow: shadow color, applied to the base of the cloud (default #cccccc).

• get_clouds(): returns a table with the current cloud parameters as in set_clouds.

• override_day_night_ratio(ratio or nil)

  • 0...1: Overrides day-night ratio, controlling sunlight to a specific amount.
  • Passing no arguments disables override, defaulting to sunlight based on day-night cycle
  • See also core.time_to_day_night_ratio,

• get_day_night_ratio(): returns the ratio or nil if it isn't overridden

• set_local_animation(idle, walk, dig, walk_while_dig, frame_speed): set animation for player model in third person view.

  • Every animation equals to a {x=starting frame, y=ending frame} table.
  • frame_speed sets the animations frame speed. Default is 30.

• get_local_animation(): returns idle, walk, dig, walk_while_dig tables and frame_speed.

• set_eye_offset([firstperson, thirdperson_back, thirdperson_front]): Sets camera offset vectors.

  • firstperson: Offset in first person view. Defaults to vector.zero() if unspecified.
  • thirdperson_back: Offset in third person back view. Clamped between vector.new(-10, -10, -5) and vector.new(10, 15, 5). Defaults to vector.zero() if unspecified.
  • thirdperson_front: Offset in third person front view. Same limits as for thirdperson_back apply. Defaults to thirdperson_back if unspecified.

• get_eye_offset(): Returns camera offset vectors as set via set_eye_offset.

• send_mapblock(blockpos):

  • Sends an already loaded mapblock to the player.
  • Returns false if nothing was sent (note that this can also mean that the client already has the block)
  • Resource intensive - use sparsely

• set_lighting(light_definition): sets lighting for the player

  • Passing no arguments resets lighting to its default values.
  • light_definition is a table with the following optional fields:
    • saturation sets the saturation (vividness; default: 1.0).
    • It is applied according to the function result = b*(1-s) + c*s, where:
      • c is the original color
      • b is the greyscale version of the color with the same luma
      • s is the saturation set here
    • The resulting color always has the same luma (perceived brightness) as the original.
    • This means that:
      • values > 1 oversaturate
      • values < 1 down to 0 desaturate, 0 being entirely greyscale
      • values < 0 cause an effect similar to inversion, but keeping original luma and being symmetrical in terms of saturation (eg. -1 and 1 is the same saturation and luma, but different hues)
    • This value has no effect on clients who have shaders or post-processing disabled.
    • shadows is a table that controls ambient shadows
    • This has no effect on clients who have the "Dynamic Shadows" effect disabled.
    • intensity sets the intensity of the shadows from 0 (no shadows, default) to 1 (blackness)
    • tint tints the shadows with the provided color, with RGB values ranging from 0 to 255. (default {r=0, g=0, b=0})
    • exposure is a table that controls automatic exposure. The basic exposure factor equation is e = 2^exposure_correction / clamp(luminance, 2^luminance_min, 2^luminance_max)
    • This has no effect on clients who have the "Automatic Exposure" effect disabled.
    • luminance_min set the lower luminance boundary to use in the calculation (default: -3.0)
    • luminance_max set the upper luminance boundary to use in the calculation (default: -3.0)
    • exposure_correction correct observed exposure by the given EV value (default: 0.0)
    • speed_dark_bright set the speed of adapting to bright light (default: 1000.0)
    • speed_bright_dark set the speed of adapting to dark scene (default: 1000.0)
    • center_weight_power set the power factor for center-weighted luminance measurement (default: 1.0)
    • bloom is a table that controls bloom.
    • This has no effect on clients with protocol version < 46 or clients who have the "Bloom" effect disabled.
    • intensity defines much bloom is applied to the rendered image.
      • Recommended range: from 0.0 to 1.0, default: 0.05
      • If set to 0, bloom is disabled.
      • The default value is to be changed from 0.05 to 0 in the future. If you wish to keep the current default value, you should set it explicitly.
    • strength_factor defines the magnitude of bloom overexposure.
      • Recommended range: from 0.1 to 10.0, default: 1.0
    • radius is a logical value that controls how far the bloom effect spreads from the bright objects.
      • Recommended range: from 0.1 to 8.0, default: 1.0
    • The behavior of values outside the recommended range is unspecified.
    • volumetric_light: is a table that controls volumetric light (a.k.a. "godrays")
    • This has no effect on clients who have the "Volumetric Lighting" or "Bloom" effects disabled.
    • strength: sets the strength of the volumetric light effect from 0 (off, default) to 1 (strongest).
      • 0.2 is a reasonable standard value.
      • Currently, bloom intensity and strength_factor affect volumetric lighting strength and vice versa. This behavior is to be changed in the future, do not rely on it.

• get_lighting(): returns the current state of lighting for the player.

  • Result is a table with the same fields as light_definition in set_lighting.

• respawn(): Respawns the player using the same mechanism as the death screen, including calling on_respawnplayer callbacks.

• get_flags(): returns a table of player flags (the following boolean fields):

  • breathing: Whether breathing (regaining air) is enabled, default true.
  • drowning: Whether drowning (losing air) is enabled, default true.
  • node_damage: Whether the player takes damage from nodes, default true.

• set_flags(flags): sets flags

  • takes a table in the same format as returned by get_flags
  • absent fields are left unchanged

PcgRandom

A 32-bit pseudorandom number generator. Uses PCG32, an algorithm of the permuted congruential generator family, offering very strong randomness.

• constructor PcgRandom(seed, [seq])
  • seed: 64-bit unsigned seed
  • seq: 64-bit unsigned sequence, optional

Methods

• next(): return next integer random number [-2147483648...2147483647]
• next(min, max): return next integer random number [min...max]
• rand_normal_dist(min, max, num_trials=6): return normally distributed random number [min...max].
  • This is only a rough approximation of a normal distribution with:
  • mean = (max - min) / 2, and
  • variance = (((max - min + 1) ^ 2) - 1) / (12 * num_trials)
  • Increasing num_trials improves accuracy of the approximation
• get_state(): return generator state encoded in string
• set_state(state_string): restore generator state from encoded string

PerlinNoise

A perlin noise generator. It can be created via PerlinNoise() or core.get_perlin(). For core.get_perlin(), the actual seed used is the noiseparams seed plus the world seed, to create world-specific noise.

PerlinNoise(noiseparams) PerlinNoise(seed, octaves, persistence, spread) (Deprecated).

core.get_perlin(noiseparams) core.get_perlin(seeddiff, octaves, persistence, spread) (Deprecated).

Methods

• get_2d(pos): returns 2D noise value at pos={x=,y=}
• get_3d(pos): returns 3D noise value at pos={x=,y=,z=}

PerlinNoiseMap

A fast, bulk perlin noise generator.

It can be created via PerlinNoiseMap(noiseparams, size) or core.get_perlin_map(noiseparams, size). For core.get_perlin_map(), the actual seed used is the noiseparams seed plus the world seed, to create world-specific noise.

Format of size is {x=dimx, y=dimy, z=dimz}. The z component is omitted for 2D noise, and it must be larger than 1 for 3D noise (otherwise nil is returned).

For each of the functions with an optional buffer parameter: If buffer is not nil, this table will be used to store the result instead of creating a new table.

Methods

• get_2d_map(pos): returns a <size.x> times <size.y> 2D array of 2D noise with values starting at pos={x=,y=}
• get_3d_map(pos): returns a <size.x> times <size.y> times <size.z> 3D array of 3D noise with values starting at pos={x=,y=,z=}.
• get_2d_map_flat(pos, buffer): returns a flat <size.x * size.y> element array of 2D noise with values starting at pos={x=,y=}
• get_3d_map_flat(pos, buffer): Same as get2dMap_flat, but 3D noise
• calc_2d_map(pos): Calculates the 2d noise map starting at pos. The result is stored internally.
• calc_3d_map(pos): Calculates the 3d noise map starting at pos. The result is stored internally.
• get_map_slice(slice_offset, slice_size, buffer): In the form of an array, returns a slice of the most recently computed noise results. The result slice begins at coordinates slice_offset and takes a chunk of slice_size. E.g. to grab a 2-slice high horizontal 2d plane of noise starting at buffer offset y = 20: noisevals = noise:get_map_slice({y=20}, {y=2}) It is important to note that slice_offset offset coordinates begin at 1, and are relative to the starting position of the most recently calculated noise. To grab a single vertical column of noise starting at map coordinates x = 1023, y=1000, z = 1000: noise:calc_3d_map({x=1000, y=1000, z=1000}) noisevals = noise:get_map_slice({x=24, z=1}, {x=1, z=1})

PlayerMetaRef

Player metadata. Uses the same method of storage as the deprecated player attribute API, so data there will also be in player meta. Can be obtained using player:get_meta().

Methods

• All methods in MetaDataRef

PseudoRandom

A 16-bit pseudorandom number generator. Uses a well-known LCG algorithm introduced by K&R.

Note: PseudoRandom is slower and has worse random distribution than PcgRandom. Use PseudoRandom only if you need output to match the well-known LCG algorithm introduced by K&R. Otherwise, use PcgRandom.

• constructor PseudoRandom(seed)
  • seed: 32-bit signed number

Methods

• next(): return next integer random number [0...32767]
• next(min, max): return next integer random number [min...max]
  • Either max - min == 32767 or max - min <= 6553 must be true due to the simple implementation making a bad distribution otherwise.
• get_state(): return state of pseudorandom generator as number
  • use returned number as seed in PseudoRandom constructor to restore

Raycast

A raycast on the map. It works with selection boxes. Can be used as an iterator in a for loop as:

local ray = Raycast(...)
for pointed_thing in ray do
    ...
end

The map is loaded as the ray advances. If the map is modified after the Raycast is created, the changes may or may not have an effect on the object.

It can be created via Raycast(pos1, pos2, objects, liquids) or core.raycast(pos1, pos2, objects, liquids) where:

• pos1: start of the ray
• pos2: end of the ray
• objects: if false, only nodes will be returned. Default is true.
• liquids: if false, liquid nodes (liquidtype ~= "none") won't be returned. Default is false.

Limitations

Raycasts don't always work properly for attached objects as the server has no knowledge of models & bones.

Rotated selectionboxes paired with automatic_rotate are not reliable either since the server can't reliably know the total rotation of the objects on different clients (which may differ on a per-client basis). The server calculates the total rotation incurred through automatic_rotate as a "best guess" assuming the object was active & rotating on the client all the time since its creation. This may be significantly out of sync with what clients see. Additionally, network latency and delayed property sending may create a mismatch of client- & server rotations.

In singleplayer mode, raycasts on objects with rotated selectionboxes & automatic rotate will usually only be slightly off; toggling automatic rotation may however cause errors to add up.

In multiplayer mode, the error may be arbitrarily large.

Methods

• next(): returns a pointed_thing with exact pointing location
  • Returns the next thing pointed by the ray or nil.

SecureRandom

Interface for the operating system's crypto-secure PRNG.

It can be created via SecureRandom(). The constructor throws an error if a secure random device cannot be found on the system.

Methods

• next_bytes([count]): return next count (default 1, capped at 2048) many random bytes, as a string.

Settings

An interface to read config files in the format of minetest.conf.

core.settings is a Settings instance that can be used to access the main config file (minetest.conf). Instances for other config files can be created via Settings(filename).

Engine settings on the core.settings object have internal defaults that will be returned if a setting is unset. The engine does not (yet) read settingtypes.txt for this purpose. This means that no defaults will be returned for mod settings.

Methods

• get(key): returns a value
  • Returns nil if key is not found.
• get_bool(key, [default]): returns a boolean
  • default is the value returned if key is not found.
  • Returns nil if key is not found and default not specified.
• get_np_group(key): returns a NoiseParams table
  • Returns nil if key is not found.
• get_flags(key):
  • Returns {flag = true/false, ...} according to the set flags.
  • Is currently limited to mapgen flags mg_flags and mapgen-specific flags like mgv5_spflags.
  • Returns nil if key is not found.
• get_pos(key):
  • Returns a vector
  • Returns nil if no value is found or parsing failed.
• set(key, value)
  • Setting names can't contain whitespace or any of ="{}#.
  • Setting values can't contain the sequence \n""".
  • Setting names starting with "secure." can't be set on the main settings object (core.settings).
• set_bool(key, value)
  • See documentation for set() above.
• set_np_group(key, value)
  • value is a NoiseParams table.
  • Also, see documentation for set() above.
• set_pos(key, value)
  • value is a vector.
  • Also, see documentation for set() above.
• remove(key): returns a boolean (true for success)
• get_names(): returns {key1,...}
• has(key):
  • Returns a boolean indicating whether key exists.
  • In contrast to the various getter functions, has() doesn't consider any default values.
  • This means that on the main settings object (core.settings), get(key) might return a value even if has(key) returns false.
• write(): returns a boolean (true for success)
  • Writes changes to file.
• to_table(): returns {[key1]=value1,...}

Format

The settings have the format key = value. Example:

foo = example text
bar = """
Multiline
value
"""

StorageRef

Mod metadata: per mod metadata, saved automatically. Can be obtained via core.get_mod_storage() during load time.

WARNING: This storage backend is incapable of saving raw binary data due to restrictions of JSON.

Methods

• All methods in MetaDataRef

Definition tables

Object properties

Used by ObjectRef methods. Part of an Entity definition. These properties are not persistent, but are applied automatically to the corresponding Lua entity using the given registration fields. Player properties need to be saved manually.

{
    hp_max = 10,
    -- Defines the maximum and default HP of the object.
    -- For Lua entities, the maximum is not enforced.
    -- For players, this defaults to `core.PLAYER_MAX_HP_DEFAULT` (20).
    -- For Lua entities, the default is 10.

    breath_max = 0,
    -- For players only. Defines the maximum amount of "breath" for the player.
    -- Defaults to `core.PLAYER_MAX_BREATH_DEFAULT` (10).

    zoom_fov = 0.0,
    -- For players only. Zoom FOV in degrees.
    -- Note that zoom loads and/or generates world beyond the server's
    -- maximum send and generate distances, so acts like a telescope.
    -- Smaller zoom_fov values increase the distance loaded/generated.
    -- Defaults to 15 in creative mode, 0 in survival mode.
    -- zoom_fov = 0 disables zooming for the player.

    eye_height = 1.625,
    -- For players only. Camera height above feet position in nodes.

    physical = false,
    -- Collide with `walkable` nodes.

    collide_with_objects = true,
    -- Collide with other objects if physical = true

    collisionbox = { -0.5, -0.5, -0.5, 0.5, 0.5, 0.5 },  -- default
    selectionbox = { -0.5, -0.5, -0.5, 0.5, 0.5, 0.5, rotate = false },
    -- { xmin, ymin, zmin, xmax, ymax, zmax } in nodes from object position.
    -- Collision boxes cannot rotate, setting `rotate = true` on it has no effect.
    -- If not set, the selection box copies the collision box, and will also not rotate.
    -- If `rotate = false`, the selection box will not rotate with the object itself, remaining fixed to the axes.
    -- If `rotate = true`, it will match the object's rotation and any attachment rotations.
    -- Raycasts use the selection box and object's rotation, but do *not* obey attachment rotations.
    -- For server-side raycasts to work correctly,
    -- the selection box should extend at most 5 units in each direction.


    pointable = true,
    -- Can be `true` if it is pointable, `false` if it can be pointed through,
    -- or `"blocking"` if it is pointable but not selectable.
    -- Clients older than 5.9.0 interpret `pointable = "blocking"` as `pointable = true`.
    -- Can be overridden by the `pointabilities` of the held item.

    visual = "cube" / "sprite" / "upright_sprite" / "mesh" / "wielditem" / "item",
    -- "cube" is a node-sized cube.
    -- "sprite" is a flat texture always facing the player.
    -- "upright_sprite" is a vertical flat texture.
    -- "mesh" uses the defined mesh model.
    -- "wielditem" is used for dropped items.
    --   (see builtin/game/item_entity.lua).
    --   For this use 'wield_item = itemname'.
    --   Setting 'textures = {itemname}' has the same effect, but is deprecated.
    --   If the item has a 'wield_image' the object will be an extrusion of
    --   that, otherwise:
    --   If 'itemname' is a cubic node or nodebox the object will appear
    --   identical to 'itemname'.
    --   If 'itemname' is a plantlike node the object will be an extrusion
    --   of its texture.
    --   Otherwise for non-node items, the object will be an extrusion of
    --   'inventory_image'.
    --   If 'itemname' contains a ColorString or palette index (e.g. from
    --   `core.itemstring_with_palette()`), the entity will inherit the color.
    --   Wielditems are scaled a bit. If you want a wielditem to appear
    --   to be as large as a node, use `0.667` in `visual_size`
    -- "item" is similar to "wielditem" but ignores the 'wield_image' parameter.

    visual_size = {x = 1, y = 1, z = 1},
    -- Multipliers for the visual size. If `z` is not specified, `x` will be used
    -- to scale the entity along both horizontal axes.

    mesh = "model.obj",
    -- File name of mesh when using "mesh" visual

    textures = {},
    -- Number of required textures depends on visual.
    -- "cube" uses 6 textures just like a node, but all 6 must be defined.
    -- "sprite" uses 1 texture.
    -- "upright_sprite" uses 2 textures: {front, back}.
    -- "mesh" requires one texture for each mesh buffer/material (in order)
    -- Deprecated usage of "wielditem" expects 'textures = {itemname}' (see 'visual' above).

    colors = {},
    -- Number of required colors depends on visual

    use_texture_alpha = false,
    -- Use texture's alpha channel.
    -- Excludes "upright_sprite" and "wielditem".
    -- Note: currently causes visual issues when viewed through other
    -- semi-transparent materials such as water.

    spritediv = {x = 1, y = 1},
    -- Used with spritesheet textures for animation and/or frame selection
    -- according to position relative to player.
    -- Defines the number of columns and rows in the spritesheet:
    -- {columns, rows}.

    initial_sprite_basepos = {x = 0, y = 0},
    -- Used with spritesheet textures.
    -- Defines the {column, row} position of the initially used frame in the
    -- spritesheet.

    is_visible = true,
    -- If false, object is invisible and can't be pointed.

    makes_footstep_sound = false,
    -- If true, is able to make footstep sounds of nodes
    -- (see node sound definition for details).

    automatic_rotate = 0,
    -- Set constant rotation in radians per second, positive or negative.
    -- Object rotates along the local Y-axis, and works with set_rotation.
    -- Set to 0 to disable constant rotation.

    stepheight = 0,
    -- If positive number, object will climb upwards when it moves
    -- horizontally against a `walkable` node, if the height difference
    -- is within `stepheight`.

    automatic_face_movement_dir = 0.0,
    -- Automatically set yaw to movement direction, offset in degrees.
    -- 'false' to disable.

    automatic_face_movement_max_rotation_per_sec = -1,
    -- Limit automatic rotation to this value in degrees per second.
    -- No limit if value <= 0.

    backface_culling = true,
    -- Set to false to disable backface_culling for model

    glow = 0,
    -- Add this much extra lighting when calculating texture color.
    -- Value < 0 disables light's effect on texture color.
    -- For faking self-lighting, UI style entities, or programmatic coloring
    -- in mods.

    nametag = "",
    -- The name to display on the head of the object. By default empty.
    -- If the object is a player, a nil or empty nametag is replaced by the player's name.
    -- For all other objects, a nil or empty string removes the nametag.
    -- To hide a nametag, set its color alpha to zero. That will disable it entirely.

    nametag_color = <ColorSpec>,
    -- Sets text color of nametag

    nametag_bgcolor = <ColorSpec>,
    -- Sets background color of nametag
    -- `false` will cause the background to be set automatically based on user settings.
    -- Default: false

    infotext = "",
    -- Same as infotext for nodes. Empty by default

    static_save = true,
    -- If false, never save this object statically. It will simply be
    -- deleted when the block gets unloaded.
    -- The get_staticdata() callback is never called then.
    -- Defaults to 'true'.

    damage_texture_modifier = "^[brighten",
    -- Texture modifier to be applied for a short duration when object is hit

    shaded = true,
    -- Setting this to 'false' disables diffuse lighting of entity

    show_on_minimap = false,
    -- Defaults to true for players, false for other entities.
    -- If set to true the entity will show as a marker on the minimap.
}

Entity definition

Used by core.register_entity. The entity definition table becomes a metatable of a newly created per-entity luaentity table, meaning its fields (e.g. initial_properties) will be shared between all instances of an entity.

{
    initial_properties = {
        visual = "mesh",
        mesh = "boats_boat.obj",
        ...,
    },
    -- A table of object properties, see the `Object properties` section.
    -- The properties in this table are applied to the object
    -- once when it is spawned.

    -- Refer to the "Registered entities" section for explanations
    on_activate = function(self, staticdata, dtime_s) end,
    on_deactivate = function(self, removal) end,
    on_step = function(self, dtime, moveresult) end,
    on_punch = function(self, puncher, time_from_last_punch, tool_capabilities, dir, damage) end,
    on_death = function(self, killer) end,
    on_rightclick = function(self, clicker) end,
    on_attach_child = function(self, child) end,
    on_detach_child = function(self, child) end,
    on_detach = function(self, parent) end,
    get_staticdata = function(self) end,

    _custom_field = whatever,
    -- You can define arbitrary member variables here (see Item definition
    -- for more info) by using a '_' prefix
}

ABM (ActiveBlockModifier) definition

Used by core.register_abm.

{
    label = "Lava cooling",
    -- Descriptive label for profiling purposes (optional).
    -- Definitions with identical labels will be listed as one.

    nodenames = {"default:lava_source"},
    -- Apply `action` function to these nodes.
    -- `group:groupname` can also be used here.

    neighbors = {"default:water_source", "default:water_flowing"},
    -- Only apply `action` to nodes that have one of, or any
    -- combination of, these neighbors.
    -- If left out or empty, any neighbor will do.
    -- `group:groupname` can also be used here.

    without_neighbors = {"default:lava_source", "default:lava_flowing"},
    -- Only apply `action` to nodes that have no one of these neighbors.
    -- If left out or empty, it has no effect.
    -- `group:groupname` can also be used here.

    interval = 10.0,
    -- Operation interval in seconds

    chance = 50,
    -- Probability of triggering `action` per-node per-interval is 1.0 / chance (integers only)

    min_y = -32768,
    max_y = 32767,
    -- min and max height levels where ABM will be processed (inclusive)
    -- can be used to reduce CPU usage

    catch_up = true,
    -- If true, catch-up behavior is enabled: The `chance` value is
    -- temporarily reduced when returning to an area to simulate time lost
    -- by the area being unattended. Note that the `chance` value can often
    -- be reduced to 1.

    action = function(pos, node, active_object_count, active_object_count_wider),
    -- Function triggered for each qualifying node.
    -- `active_object_count` is number of active objects in the node's
    -- mapblock.
    -- `active_object_count_wider` is number of active objects in the node's
    -- mapblock plus all 26 neighboring mapblocks. If any neighboring
    -- mapblocks are unloaded an estimate is calculated for them based on
    -- loaded mapblocks.
}

LBM (LoadingBlockModifier) definition

Used by core.register_lbm.

A loading block modifier (LBM) is used to define a function that is called for specific nodes (defined by nodenames) when a mapblock which contains such nodes gets activated (not loaded!).

Note: LBMs operate on a "snapshot" of node positions taken once before they are triggered. That means if an LBM callback adds a node, it won't be taken into account. However the engine guarantees that when the callback is called that all given position(s) contain a matching node.

{
    label = "Upgrade legacy doors",
    -- Descriptive label for profiling purposes (optional).
    -- Definitions with identical labels will be listed as one.

    name = "modname:replace_legacy_door",
    -- Identifier of the LBM, should follow the modname:<whatever> convention

    nodenames = {"default:lava_source"},
    -- List of node names to trigger the LBM on.
    -- Names of non-registered nodes and groups (as group:groupname)
    -- will work as well.

    run_at_every_load = false,
    -- Whether to run the LBM's action every time a block gets activated,
    -- and not only the first time the block gets activated after the LBM
    -- was introduced.

    action = function(pos, node, dtime_s) end,
    -- Function triggered for each qualifying node.
    -- `dtime_s` is the in-game time (in seconds) elapsed since the block
    -- was last active.

    bulk_action = function(pos_list, dtime_s) end,
    -- Function triggered with a list of all applicable node positions at once.
    -- This can be provided as an alternative to `action` (not both).
    -- Available since `core.features.bulk_lbms` (5.10.0)
    -- `dtime_s`: as above
}

Tile definition

• "image.png"
• {name="image.png", animation={Tile Animation definition}}
• {name="image.png", backface_culling=bool, align_style="node"/"world"/"user", scale=int}
  • backface culling enabled by default for most nodes
  • align style determines whether the texture will be rotated with the node or kept aligned with its surroundings. "user" means that client setting will be used, similar to glasslike_framed_optional. Note: supported by solid nodes and nodeboxes only.
  • scale is used to make texture span several (exactly scale) nodes, instead of just one, in each direction. Works for world-aligned textures only. Note that as the effect is applied on per-mapblock basis, 16 should be equally divisible by scale or you may get wrong results.
• {name="image.png", color=ColorSpec}
  • the texture's color will be multiplied with this color.
  • the tile's color overrides the owning node's color in all cases.
• deprecated, yet still supported field names:
  • image (name)

Tile animation definition

{
    type = "vertical_frames",

    aspect_w = 16,
    -- Width of a frame in pixels

    aspect_h = 16,
    -- Height of a frame in pixels

    length = 3.0,
    -- Full loop length
}

{
    type = "sheet_2d",

    frames_w = 5,
    -- Width in number of frames

    frames_h = 3,
    -- Height in number of frames

    frame_length = 0.5,
    -- Length of a single frame
}

Item definition

Used by core.register_node, core.register_craftitem, and core.register_tool.

{
    description = "",
    -- Can contain new lines. "\n" has to be used as new line character.
    -- See also: `get_description` in [`ItemStack`]

    short_description = "",
    -- Must not contain new lines.
    -- Defaults to nil.
    -- Use an [`ItemStack`] to get the short description, e.g.:
    --   ItemStack(itemname):get_short_description()

    groups = {},
    -- key = name, value = rating; rating = <number>.
    -- If rating not applicable, use 1.
    -- e.g. {wool = 1, fluffy = 3}
    --      {soil = 2, outerspace = 1, crumbly = 1}
    --      {bendy = 2, snappy = 1},
    --      {hard = 1, metal = 1, spikes = 1}

    inventory_image = "",
    -- Texture shown in the inventory GUI
    -- Defaults to a 3D rendering of the node if left empty.

    inventory_overlay = "",
    -- An overlay texture which is not affected by colorization

    wield_image = "",
    -- Texture shown when item is held in hand
    -- Defaults to a 3D rendering of the node if left empty.

    wield_overlay = "",
    -- Like inventory_overlay but only used in the same situation as wield_image

    wield_scale = {x = 1, y = 1, z = 1},
    -- Scale for the item when held in hand

    palette = "",
    -- An image file containing the palette of a node.
    -- You can set the currently used color as the "palette_index" field of
    -- the item stack metadata.
    -- The palette is always stretched to fit indices between 0 and 255, to
    -- ensure compatibility with "colorfacedir" (and similar) nodes.

    color = "#ffffffff",
    -- Color the item is colorized with. The palette overrides this.

    stack_max = 99,
    -- Maximum amount of items that can be in a single stack.
    -- The default can be changed by the setting `default_stack_max`

    range = 4.0,
    -- Range of node and object pointing that is possible with this item held
    -- Can be overridden with itemstack meta.

    liquids_pointable = false,
    -- If true, item can point to all liquid nodes (`liquidtype ~= "none"`),
    -- even those for which `pointable = false`

    pointabilities = {
        nodes = {
            ["default:stone"] = "blocking",
            ["group:leaves"] = false,
        },
        objects = {
            ["modname:entityname"] = true,
            ["group:ghosty"] = true, -- (an armor group)
        },
    },
    -- Contains lists to override the `pointable` property of nodes and objects.
    -- The index can be a node/entity name or a group with the prefix `"group:"`.
    -- (For objects `armor_groups` are used and for players the entity name is irrelevant.)
    -- If multiple fields fit, the following priority order is applied:
    -- 1. value of matching node/entity name
    -- 2. `true` for any group
    -- 3. `false` for any group
    -- 4. `"blocking"` for any group
    -- 5. `liquids_pointable` if it is a liquid node
    -- 6. `pointable` property of the node or object

    light_source = 0,
    -- When used for nodes: Defines amount of light emitted by node.
    -- Otherwise: Defines texture glow when viewed as a dropped item
    -- To set the maximum (14), use the value 'core.LIGHT_MAX'.
    -- A value outside the range 0 to core.LIGHT_MAX causes undefined
    -- behavior.

    -- See "Tool Capabilities" section for an example including explanation
    tool_capabilities = {
        full_punch_interval = 1.0,
        max_drop_level = 0,
        groupcaps = {
            -- For example:
            choppy = {times = {2.50, 1.40, 1.00}, uses = 20, maxlevel = 2},
        },
        damage_groups = {groupname = damage},
        -- Damage values must be between -32768 and 32767 (2^15)

        punch_attack_uses = nil,
        -- Amount of uses this tool has for attacking players and entities
        -- by punching them (0 = infinite uses).
        -- For compatibility, this is automatically set from the first
        -- suitable groupcap using the formula "uses * 3^(maxlevel - 1)".
        -- It is recommend to set this explicitly instead of relying on the
        -- fallback behavior.
    },

    -- Set wear bar color of the tool by setting color stops and blend mode
    -- See "Wear Bar Color" section for further explanation including an example
    wear_color = {
        -- interpolation mode: 'constant' or 'linear'
        -- (nil defaults to 'constant')
        blend = "linear",
        color_stops = {
            [0.0] = "#ff0000",
            [0.5] = "#ffff00",
            [1.0] = "#00ff00",
        }
    },

    node_placement_prediction = nil,
    -- If nil and item is node, prediction is made automatically.
    -- If nil and item is not a node, no prediction is made.
    -- If "" and item is anything, no prediction is made.
    -- Otherwise should be name of node which the client immediately places
    -- on ground when the player places the item. Server will always update
    -- with actual result shortly.

    node_dig_prediction = "air",
    -- if "", no prediction is made.
    -- if "air", node is removed.
    -- Otherwise should be name of node which the client immediately places
    -- upon digging. Server will always update with actual result shortly.

    touch_interaction = <TouchInteractionMode> OR {
        pointed_nothing = <TouchInteractionMode>,
        pointed_node    = <TouchInteractionMode>,
        pointed_object  = <TouchInteractionMode>,
    },
      -- Only affects touchscreen clients.
      -- Defines the meaning of short and long taps with the item in hand.
      -- If specified as a table, the field to be used is selected according to
      -- the current `pointed_thing`.
      -- There are three possible TouchInteractionMode values:
      -- * "long_dig_short_place" (long tap  = dig, short tap = place)
      -- * "short_dig_long_place" (short tap = dig, long tap  = place)
      -- * "user":
      --   * For `pointed_object`: Equivalent to "short_dig_long_place" if the
      --     client-side setting "touch_punch_gesture" is "short_tap" (the
      --     default value) and the item is able to punch (i.e. has no on_use
      --     callback defined).
      --     Equivalent to "long_dig_short_place" otherwise.
      --   * For `pointed_node` and `pointed_nothing`:
      --     Equivalent to "long_dig_short_place".
      --   * The behavior of "user" may change in the future.
      -- The default value is "user".

    sound = {
        -- Definition of item sounds to be played at various events.
        -- All fields in this table are optional.

        breaks = <SimpleSoundSpec>,
        -- When tool breaks due to wear. Ignored for non-tools

        eat = <SimpleSoundSpec>,
        -- When item is eaten with `core.do_item_eat`

        punch_use = <SimpleSoundSpec>,
        -- When item is used with the 'punch/mine' key pointing at a node or entity

        punch_use_air = <SimpleSoundSpec>,
        -- When item is used with the 'punch/mine' key pointing at nothing (air)
    },

    on_place = function(itemstack, placer, pointed_thing),
    -- When the 'place' key was pressed with the item in hand
    -- and a node was pointed at.
    -- Shall place item and return the leftover itemstack
    -- or nil to not modify the inventory.
    -- The placer may be any ObjectRef or nil.
    -- default: core.item_place

    on_secondary_use = function(itemstack, user, pointed_thing),
    -- Same as on_place but called when not pointing at a node.
    -- Function must return either nil if inventory shall not be modified,
    -- or an itemstack to replace the original itemstack.
    -- The user may be any ObjectRef or nil.
    -- default: nil

    on_drop = function(itemstack, dropper, pos),
    -- Shall drop item and return the leftover itemstack.
    -- The dropper may be any ObjectRef or nil.
    -- default: core.item_drop

    on_pickup = function(itemstack, picker, pointed_thing, time_from_last_punch, ...),
    -- Called when a dropped item is punched by a player.
    -- Shall pick-up the item and return the leftover itemstack or nil to not
    -- modify the dropped item.
    -- Parameters:
    -- * `itemstack`: The `ItemStack` to be picked up.
    -- * `picker`: Any `ObjectRef` or `nil`.
    -- * `pointed_thing` (optional): The dropped item (a `"__builtin:item"`
    --   luaentity) as `type="object"` `pointed_thing`.
    -- * `time_from_last_punch, ...` (optional): Other parameters from
    --   `luaentity:on_punch`.
    -- default: `core.item_pickup`

    on_use = function(itemstack, user, pointed_thing),
    -- default: nil
    -- When user pressed the 'punch/mine' key with the item in hand.
    -- Function must return either nil if inventory shall not be modified,
    -- or an itemstack to replace the original itemstack.
    -- e.g. itemstack:take_item(); return itemstack
    -- Otherwise, the function is free to do what it wants.
    -- The user may be any ObjectRef or nil.
    -- The default functions handle regular use cases.

    after_use = function(itemstack, user, node, digparams),
    -- default: nil
    -- If defined, should return an itemstack and will be called instead of
    -- wearing out the item (if tool). If returns nil, does nothing.
    -- If after_use doesn't exist, it is the same as:
    --   function(itemstack, user, node, digparams)
    --     itemstack:add_wear(digparams.wear)
    --     return itemstack
    --   end
    -- The user may be any ObjectRef or nil.

    _custom_field = whatever,
    -- Add your own custom fields. By convention, all custom field names
    -- should start with `_` to avoid naming collisions with future engine
    -- usage.
}

Node definition

Used by core.register_node.

{
    -- <all fields allowed in item definitions>

    drawtype = "normal",  -- See "Node drawtypes"

    visual_scale = 1.0,
    -- Supported for drawtypes "plantlike", "signlike", "torchlike",
    -- "firelike", "mesh", "nodebox", "allfaces".
    -- For plantlike and firelike, the image will start at the bottom of the
    -- node. For torchlike, the image will start at the surface to which the
    -- node "attaches". For the other drawtypes the image will be centered
    -- on the node.

    tiles = {tile definition 1, def2, def3, def4, def5, def6},
    -- Textures of node; +Y, -Y, +X, -X, +Z, -Z
    -- List can be shortened to needed length.

    overlay_tiles = {tile definition 1, def2, def3, def4, def5, def6},
    -- Same as `tiles`, but these textures are drawn on top of the base
    -- tiles. You can use this to colorize only specific parts of your
    -- texture. If the texture name is an empty string, that overlay is not
    -- drawn. Since such tiles are drawn twice, it is not recommended to use
    -- overlays on very common nodes.

    special_tiles = {tile definition 1, Tile definition 2},
    -- Special textures of node; used rarely.
    -- List can be shortened to needed length.

    color = ColorSpec,
    -- The node's original color will be multiplied with this color.
    -- If the node has a palette, then this setting only has an effect in
    -- the inventory and on the wield item.

    use_texture_alpha = ...,
    -- Specifies how the texture's alpha channel will be used for rendering.
    -- Possible values:
    -- * "opaque":
    --   Node is rendered opaque regardless of alpha channel.
    -- * "clip":
    --   A given pixel is either fully see-through or opaque
    --   depending on the alpha channel being below/above 50% in value.
    --   Use this for nodes with fully transparent and fully opaque areas.
    -- * "blend":
    --   The alpha channel specifies how transparent a given pixel
    --   of the rendered node is. This comes at a performance cost.
    --   Only use this when correct rendering
    --   among semitransparent nodes is necessary.
    -- The default is "opaque" for drawtypes normal, liquid and flowingliquid,
    -- mesh and nodebox or "clip" otherwise.
    -- If set to a boolean value (deprecated): true either sets it to blend
    -- or clip, false sets it to clip or opaque mode depending on the drawtype.

    palette = "",
    -- The node's `param2` is used to select a pixel from the image.
    -- Pixels are arranged from left to right and from top to bottom.
    -- The node's color will be multiplied with the selected pixel's color.
    -- Tiles can override this behavior.
    -- Only when `paramtype2` supports palettes.

    post_effect_color = "#00000000",
    -- Screen tint if a player is inside this node, see `ColorSpec`.
    -- Color is alpha-blended over the screen.

    post_effect_color_shaded = false,
    -- Determines whether `post_effect_color` is affected by lighting.

    paramtype = "none",  -- See "Nodes"

    paramtype2 = "none",  -- See "Nodes"

    place_param2 = 0,
    -- Value for param2 that is set when player places node

    wallmounted_rotate_vertical = false,
    -- If true, place_param2 is nil, and this is a wallmounted node,
    -- this node might use the special 90° rotation when placed
    -- on the floor or ceiling, depending on the direction.
    -- See the explanation about wallmounted for details.
    -- Otherwise, the rotation is always the same on vertical placement.

    is_ground_content = true,
    -- If false, the cave generator and dungeon generator will not carve
    -- through this node.
    -- Specifically, this stops mod-added nodes being removed by caves and
    -- dungeons when those generate in a neighbor mapchunk and extend out
    -- beyond the edge of that mapchunk.

    sunlight_propagates = false,
    -- If true, sunlight will go infinitely through this node

    walkable = true,  -- If true, objects collide with node

    pointable = true,
    -- Can be `true` if it is pointable, `false` if it can be pointed through,
    -- or `"blocking"` if it is pointable but not selectable.
    -- Clients older than 5.9.0 interpret `pointable = "blocking"` as `pointable = true`.
    -- Can be overridden by the `pointabilities` of the held item.
    -- A client may be able to point non-pointable nodes, since it isn't checked server-side.

    diggable = true,  -- If false, can never be dug

    climbable = false,  -- If true, can be climbed on like a ladder

    move_resistance = 0,
    -- Slows down movement of players through this node (max. 7).
    -- If this is nil, it will be equal to liquid_viscosity.
    -- Note: If liquid movement physics apply to the node
    -- (see `liquid_move_physics`), the movement speed will also be
    -- affected by the `movement_liquid_*` settings.

    buildable_to = false,  -- If true, placed nodes can replace this node

    floodable = false,
    -- If true, liquids flow into and replace this node.
    -- Warning: making a liquid node 'floodable' will cause problems.

    liquidtype = "none",  -- specifies liquid flowing physics
    -- * "none":    no liquid flowing physics
    -- * "source":  spawns flowing liquid nodes at all 4 sides and below;
    --              recommended drawtype: "liquid".
    -- * "flowing": spawned from source, spawns more flowing liquid nodes
    --              around it until `liquid_range` is reached;
    --              will drain out without a source;
    --              recommended drawtype: "flowingliquid".
    -- If it's "source" or "flowing", then the
    -- `liquid_alternative_*` fields _must_ be specified

    liquid_alternative_flowing = "",
    liquid_alternative_source = "",
    -- These fields may contain node names that represent the
    -- flowing version (`liquid_alternative_flowing`) and
    -- source version (`liquid_alternative_source`) of a liquid.
    --
    -- Specifically, these fields are required if `liquidtype ~= "none"` or
    -- `drawtype == "flowingliquid"`.
    --
    -- Liquids consist of up to two nodes: source and flowing.
    --
    -- There are two ways to define a liquid:
    -- 1) Source node and flowing node. This requires both fields to be
    --    specified for both nodes.
    -- 2) Standalone source node (cannot flow). `liquid_alternative_source`
    --    must be specified and `liquid_range` must be set to 0.
    --
    -- Example:
    --     liquid_alternative_flowing = "example:water_flowing",
    --     liquid_alternative_source = "example:water_source",

    liquid_viscosity = 0,
    -- Controls speed at which the liquid spreads/flows (max. 7).
    -- 0 is fastest, 7 is slowest.
    -- By default, this also slows down movement of players inside the node
    -- (can be overridden using `move_resistance`)

    liquid_renewable = true,
    -- If true, a new liquid source can be created by placing two or more
    -- sources nearby

    liquid_move_physics = nil, -- specifies movement physics if inside node
    -- * false: No liquid movement physics apply.
    -- * true: Enables liquid movement physics. Enables things like
    --   ability to "swim" up/down, sinking slowly if not moving,
    --   smoother speed change when falling into, etc. The `movement_liquid_*`
    --   settings apply.
    -- * nil: Will be treated as true if `liquidtype ~= "none"`
    --   and as false otherwise.

    air_equivalent = nil,
    -- unclear meaning, the engine sets this to true for 'air' and 'ignore'
    -- deprecated.

    leveled = 0,
    -- Only valid for "nodebox" drawtype with 'type = "leveled"'.
    -- Allows defining the nodebox height without using param2.
    -- The nodebox height is 'leveled' / 64 nodes.
    -- The maximum value of 'leveled' is `leveled_max`.

    leveled_max = 127,
    -- Maximum value for `leveled` (0-127), enforced in
    -- `core.set_node_level` and `core.add_node_level`.
    -- Values above 124 might causes collision detection issues.

    liquid_range = 8,
    -- Maximum distance that flowing liquid nodes can spread around
    -- source on flat land;
    -- maximum = 8; set to 0 to disable liquid flow

    drowning = 0,
    -- Player will take this amount of damage if no bubbles are left

    damage_per_second = 0,
    -- If player is inside node, this damage is caused

    node_box = {type = "regular"},  -- See "Node boxes"

    connects_to = {},
    -- Used for nodebox nodes with the type == "connected".
    -- Specifies to what neighboring nodes connections will be drawn.
    -- e.g. `{"group:fence", "default:wood"}` or `"default:stone"`

    connect_sides = {},
    -- Tells connected nodebox nodes to connect only to these sides of this
    -- node. possible: "top", "bottom", "front", "left", "back", "right"

    mesh = "",
    -- File name of mesh when using "mesh" drawtype

    selection_box = {
        -- see [Node boxes] for possibilities
    },
    -- Custom selection box definition. Multiple boxes can be defined.
    -- If "nodebox" drawtype is used and selection_box is nil, then node_box
    -- definition is used for the selection box.

    collision_box = {
        -- see [Node boxes] for possibilities
    },
    -- Custom collision box definition. Multiple boxes can be defined.
    -- If "nodebox" drawtype is used and collision_box is nil, then node_box
    -- definition is used for the collision box.

    -- Support maps made in and before January 2012
    legacy_facedir_simple = false,
    legacy_wallmounted = false,

    waving = 0,
    -- Valid for drawtypes:
    -- mesh, nodebox, plantlike, allfaces_optional, liquid, flowingliquid.
    -- 1 - wave node like plants (node top moves side-to-side, bottom is fixed)
    -- 2 - wave node like leaves (whole node moves side-to-side)
    -- 3 - wave node like liquids (whole node moves up and down)
    -- Not all models will properly wave.
    -- plantlike drawtype can only wave like plants.
    -- allfaces_optional drawtype can only wave like leaves.
    -- liquid, flowingliquid drawtypes can only wave like liquids.

    sounds = {
        -- Definition of node sounds to be played at various events.
        -- All fields in this table are optional.

        footstep = <SimpleSoundSpec>,
        -- If walkable, played when object walks on it. If node is
        -- climbable or a liquid, played when object moves through it.
        -- Sound is played at the base of the object's collision-box.
        -- Gain is multiplied by `0.6`.
        -- For local player, it's played position-less, with normal gain.

        dig = <SimpleSoundSpec> or "__group",
        -- While digging node.
        -- If `"__group"`, then the sound will be
        -- `{name = "default_dig_<groupname>", gain = 0.5}` , where `<groupname>` is the
        -- name of the item's digging group with the fastest digging time.
        -- In case of a tie, one of the sounds will be played (but we
        -- cannot predict which one)
        -- Default value: `"__group"`

        dug = <SimpleSoundSpec>,
        -- Node was dug

        place = <SimpleSoundSpec>,
        -- Node was placed. Also played after falling

        place_failed = <SimpleSoundSpec>,
        -- When node placement failed.
        -- Note: This happens if the _built-in_ node placement failed.
        -- This sound will still be played if the node is placed in the
        -- `on_place` callback manually.

        fall = <SimpleSoundSpec>,
        -- When node starts to fall or is detached
    },

    drop = "",
    -- Name of dropped item when dug.
    -- Default dropped item is the node itself.

    -- Using a table allows multiple items, drop chances and item filtering:
    drop = {
        max_items = 1,
        -- Maximum number of item lists to drop.
        -- The entries in 'items' are processed in order. For each:
        -- Item filtering is applied, chance of drop is applied, if both are
        -- successful the entire item list is dropped.
        -- Entry processing continues until the number of dropped item lists
        -- equals 'max_items'.
        -- Therefore, entries should progress from low to high drop chance.
        items = {
            -- Examples:
            {
                -- 1 in 1000 chance of dropping a diamond.
                -- Default rarity is '1'.
                rarity = 1000,
                items = {"default:diamond"},
            },
            {
                -- Only drop if using an item whose name is identical to one
                -- of these.
                tools = {"default:shovel_mese", "default:shovel_diamond"},
                rarity = 5,
                items = {"default:dirt"},
                -- Whether all items in the dropped item list inherit the
                -- hardware coloring palette color from the dug node.
                -- Default is 'false'.
                inherit_color = true,
            },
            {
                -- Only drop if using an item whose name contains
                -- "default:shovel_" (this item filtering by string matching
                -- is deprecated, use tool_groups instead).
                tools = {"~default:shovel_"},
                rarity = 2,
                -- The item list dropped.
                items = {"default:sand", "default:desert_sand"},
            },
            {
                -- Only drop if using an item in the "magicwand" group, or
                -- an item that is in both the "pickaxe" and the "lucky"
                -- groups.
                tool_groups = {
                    "magicwand",
                    {"pickaxe", "lucky"}
                },
                items = {"default:coal_lump"},
            },
        },
    },

    on_construct = function(pos),
    -- Node constructor; called after adding node.
    -- Can set up metadata and stuff like that.
    -- Not called for bulk node placement (i.e. schematics and VoxelManip).
    -- Note: Within an on_construct callback, core.set_node can cause an
    -- infinite loop if it invokes the same callback.
    --  Consider using core.swap_node instead.
    -- default: nil

    on_destruct = function(pos),
    -- Node destructor; called before removing node.
    -- Not called for bulk node placement.
    -- default: nil

    after_destruct = function(pos, oldnode),
    -- Node destructor; called after removing node.
    -- Not called for bulk node placement.
    -- default: nil

    on_flood = function(pos, oldnode, newnode),
    -- Called when a liquid (newnode) is about to flood oldnode, if it has
    -- `floodable = true` in the nodedef. Not called for bulk node placement
    -- (i.e. schematics and VoxelManip) or air nodes. If return true the
    -- node is not flooded, but on_flood callback will most likely be called
    -- over and over again every liquid update interval.
    -- Default: nil
    -- Warning: making a liquid node 'floodable' will cause problems.

    preserve_metadata = function(pos, oldnode, oldmeta, drops),
    -- Called when `oldnode` is about be converted to an item, but before the
    -- node is deleted from the world or the drops are added. This is
    -- generally the result of either the node being dug or an attached node
    -- becoming detached.
    -- * `pos`: node position
    -- * `oldnode`: node table of node before it was deleted
    -- * `oldmeta`: metadata of node before it was deleted, as a metadata table
    -- * `drops`: a table of `ItemStack`s, so any metadata to be preserved can
    --   be added directly to one or more of the dropped items. See
    --   "ItemStackMetaRef".
    -- default: `nil`

    after_place_node = function(pos, placer, itemstack, pointed_thing),
    -- Called after constructing node when node was placed using
    -- core.item_place_node / core.place_node.
    -- If return true no item is taken from itemstack.
    -- `placer` may be any valid ObjectRef or nil.
    -- default: nil

    after_dig_node = function(pos, oldnode, oldmetadata, digger),
    -- Called after destructing the node when node was dug using
    -- `core.node_dig` / `core.dig_node`.
    -- * `pos`: node position
    -- * `oldnode`: node table of node before it was dug
    -- * `oldmetadata`: metadata of node before it was dug,
    --                  as a metadata table
    -- * `digger`: ObjectRef of digger
    -- default: nil

    can_dig = function(pos, [player]),
    -- Returns true if node can be dug, or false if not.
    -- default: nil

    on_punch = function(pos, node, puncher, pointed_thing),
    -- default: core.node_punch
    -- Called when puncher (an ObjectRef) punches the node at pos.
    -- By default calls core.register_on_punchnode callbacks.

    on_rightclick = function(pos, node, clicker, itemstack, pointed_thing),
    -- default: nil
    -- Called when clicker (an ObjectRef) used the 'place/build' key
    -- (not necessarily an actual rightclick)
    -- while pointing at the node at pos with 'node' being the node table.
    -- itemstack will hold clicker's wielded item.
    -- Shall return the leftover itemstack.
    -- Note: pointed_thing can be nil, if a mod calls this function.
    -- This function does not get triggered by clients <=0.4.16 if the
    -- "formspec" node metadata field is set.

    on_dig = function(pos, node, digger),
    -- default: core.node_dig
    -- By default checks privileges, wears out item (if tool) and removes node.
    -- return true if the node was dug successfully, false otherwise.
    -- Deprecated: returning nil is the same as returning true.

    on_timer = function(pos, elapsed),
    -- default: nil
    -- called by NodeTimers, see core.get_node_timer and NodeTimerRef.
    -- elapsed is the total time passed since the timer was started.
    -- return true to run the timer for another cycle with the same timeout
    -- value.

    on_receive_fields = function(pos, formname, fields, sender),
    -- fields = {name1 = value1, name2 = value2, ...}
    -- formname should be the empty string; you **must not** use formname.
    -- Called when an UI form (e.g. sign text input) returns data.
    -- See core.register_on_player_receive_fields for more info.
    -- default: nil

    allow_metadata_inventory_move = function(pos, from_list, from_index, to_list, to_index, count, player),
    -- Called when a player wants to move items inside the inventory.
    -- Return value: number of items allowed to move.

    allow_metadata_inventory_put = function(pos, listname, index, stack, player),
    -- Called when a player wants to put something into the inventory.
    -- Return value: number of items allowed to put.
    -- Return value -1: Allow and don't modify item count in inventory.

    allow_metadata_inventory_take = function(pos, listname, index, stack, player),
    -- Called when a player wants to take something out of the inventory.
    -- Return value: number of items allowed to take.
    -- Return value -1: Allow and don't modify item count in inventory.

    on_metadata_inventory_move = function(pos, from_list, from_index, to_list, to_index, count, player),
    on_metadata_inventory_put = function(pos, listname, index, stack, player),
    on_metadata_inventory_take = function(pos, listname, index, stack, player),
    -- Called after the actual action has happened, according to what was
    -- allowed.
    -- No return value.

    on_blast = function(pos, intensity),
    -- intensity: 1.0 = mid range of regular TNT.
    -- If defined, called when an explosion touches the node, instead of
    -- removing the node.

    mod_origin = "modname",
    -- stores which mod actually registered a node
    -- If the source could not be determined it contains "??"
    -- Useful for getting which mod truly registered something
    -- example: if a node is registered as ":othermodname:nodename",
    -- nodename will show "othermodname", but mod_origin will say "modname"
}

Wear Bar Color

'Wear Bar' is a property of items that defines the coloring of the bar that appears under damaged tools. If it is absent, the default behavior of green-yellow-red is used.

Wear bar colors definition

Syntax

{
    -- 'constant' or 'linear'
    -- (nil defaults to 'constant')
    blend = "linear",
    color_stops = {
        [0.0] = "#ff0000",
        [0.5] = "slateblue",
        [1.0] = {r=0, g=255, b=0, a=150},
    }
}

Blend mode blend

• linear: blends smoothly between each defined color point.
• constant: each color starts at its defined point, and continues up to the next point

Color stops color_stops

Specified as ColorSpec color values assigned to float durability keys.

"Durability" is defined as 1 - (wear / 65535).

Shortcut usage

Wear bar color can also be specified as a single ColorSpec instead of a table.

Crafting recipes

Crafting converts one or more inputs to one output itemstack of arbitrary count (except for fuels, which don't have an output). The conversion reduces each input ItemStack by 1.

Craft recipes are registered by core.register_craft and use a table format. The accepted parameters are listed below.

Recipe input items can either be specified by item name (item count = 1) or by group (see "Groups in crafting recipes" for details).

The following sections describe the types and syntaxes of recipes.

Shaped

This is the default recipe type (when no type is specified).

A shaped recipe takes one or multiple items as input and has a single item stack as output. The input items must be specified in a 2-dimensional matrix (see parameters below) to specify the exact arrangement (the "shape") in which the player must place them in the crafting grid.

For example, for a 3x3 recipe, the recipes table must have 3 rows and 3 columns.

In order to craft the recipe, the players' crafting grid must have equal or larger dimensions (both width and height).

Parameters:

• type = "shaped": (optional) specifies recipe type as shaped
• output: Itemstring of output itemstack (item counts >= 1 are allowed)
• recipe: A 2-dimensional matrix of items, with a width w and height h.
  • w and h are chosen by you, they don't have to be equal but must be at least 1
  • The matrix is specified as a table containing tables containing itemnames
  • The inner tables are the rows. There must be h tables, specified from the top to the bottom row
  • Values inside of the inner table are the columns. Each inner table must contain a list of w items, specified from left to right
  • Empty slots must be filled with the empty string
• replacements: (optional) Allows you to replace input items with some other items when something is crafted
  • Provided as a list of item pairs of the form { old_item, new_item } where old_item is the input item to replace (same syntax as for a regular input slot; groups are allowed) and new_item is an itemstring for the item stack it will become
  • When the output is crafted, Luanti iterates through the list of input items if the crafting grid. For each input item stack, it checks if it matches with an old_item in the item pair list.
    • If it matches, the item will be replaced. Also, this item pair will not be applied again for the remaining items
    • If it does not match, the item is consumed (reduced by 1) normally
  • The new_item will appear in one of 3 places:
    • Crafting grid, if the input stack size was exactly 1
    • Player inventory, if input stack size was larger
    • Drops as item entity, if it fits neither in craft grid or inventory

Examples

A typical shaped recipe:

-- Stone pickaxe
{
    output = "example:stone_pickaxe",
    -- A 3x3 recipe which needs 3 stone in the 1st row,
    -- and 1 stick in the horizontal middle in each of the 2nd and 3nd row.
    -- The 4 remaining slots have to be empty.
    recipe = {
        {"example:stone", "example:stone", "example:stone"}, -- row 1
        {"",              "example:stick", ""             }, -- row 2
        {"",              "example:stick", ""             }, -- row 3
    --   ^ column 1       ^ column 2       ^ column 3
    },
    -- There is no replacements table, so every input item
    -- will be consumed.
}

Simple replacement example:

-- Wet sponge
{
    output = "example:wet_sponge",
    -- 1x2 recipe with a water bucket above a dry sponge
    recipe = {
        {"example:water_bucket"},
        {"example:dry_sponge"},
    },
    -- When the wet sponge is crafted, the water bucket
    -- in the input slot is replaced with an empty
    -- bucket
    replacements = {
        {"example:water_bucket", "example:empty_bucket"},
    },
}

Complex replacement example 1:

-- Very wet sponge
{
    output = "example:very_wet_sponge",
    -- 3x3 recipe with a wet sponge in the center
    -- and 4 water buckets around it
    recipe = {
        {"","example:water_bucket",""},
        {"example:water_bucket","example:wet_sponge","example:water_bucket"},
        {"","example:water_bucket",""},
    },
    -- When the wet sponge is crafted, all water buckets
    -- in the input slot become empty
    replacements = {
        -- Without these repetitions, only the first
        -- water bucket would be replaced.
        {"example:water_bucket", "example:empty_bucket"},
        {"example:water_bucket", "example:empty_bucket"},
        {"example:water_bucket", "example:empty_bucket"},
        {"example:water_bucket", "example:empty_bucket"},
    },
}

Complex replacement example 2:

-- Magic book:
-- 3 magic orbs + 1 book crafts a magic book,
-- and the orbs will be replaced with 3 different runes.
{
    output = "example:magic_book",
    -- 3x2 recipe
    recipe = {
        -- 3 items in the group `magic_orb` on top of a book in the middle
        {"group:magic_orb", "group:magic_orb", "group:magic_orb"},
        {"", "example:book", ""},
    },
    -- When the book is crafted, the 3 magic orbs will be turned into
    -- 3 runes: ice rune, earth rune and fire rune (from left to right)
    replacements = {
        {"group:magic_orb", "example:ice_rune"},
        {"group:magic_orb", "example:earth_rune"},
        {"group:magic_orb", "example:fire_rune"},
    },
}

Shapeless

Takes a list of input items (at least 1). The order or arrangement of input items does not matter.

In order to craft the recipe, the players' crafting grid must have matching or larger count of slots. The grid dimensions do not matter.

Parameters:

• type = "shapeless": Mandatory
• output: Same as for shaped recipe
• recipe: List of item names
• replacements: Same as for shaped recipe

Example

{
    -- Craft a mushroom stew from a bowl, a brown mushroom and a red mushroom
    -- (no matter where in the input grid the items are placed)
    type = "shapeless",
    output = "example:mushroom_stew",
    recipe = {
        "example:bowl",
        "example:mushroom_brown",
        "example:mushroom_red",
    },
}

Tool repair

Syntax:

{
    type = "toolrepair",
    additional_wear = -0.02, -- multiplier of 65536
}

Adds a shapeless recipe for every tool that doesn't have the disable_repair=1 group. If this recipe is used, repairing is possible with any crafting grid with at least 2 slots. The player can put 2 equal tools in the craft grid to get one "repaired" tool back. The wear of the output is determined by the wear of both tools, plus a 'repair bonus' given by additional_wear. To reduce the wear (i.e. 'repair'), you want additional_wear to be negative.

The formula used to calculate the resulting wear is:

65536 * (1 - ( (1 - tool_1_wear) + (1 - tool_2_wear) + additional_wear))

The result is rounded and can't be lower than 0. If the result is 65536 or higher, no crafting is possible.

Cooking

A cooking recipe has a single input item, a single output item stack and a cooking time. It represents cooking/baking/smelting/etc. items in an oven, furnace, or something similar; the exact meaning is up for games to decide, if they choose to use cooking at all.

The engine does not implement anything specific to cooking recipes, but the recipes can be retrieved later using core.get_craft_result to have a consistent interface across different games/mods.

Parameters:

• type = "cooking": Mandatory
• output: Same as for shaped recipe
• recipe: An itemname of the single input item
• cooktime: (optional) Time it takes to cook this item, in seconds. A floating-point number. (default: 3.0)
• replacements: Same meaning as for shaped recipes, but the mods that utilize cooking recipes (e.g. for adding a furnace node) need to implement replacements on their own

Note: Games and mods are free to re-interpret the cooktime in special cases, e.g. for a super furnace that cooks items twice as fast.

Example

Cooking sand to glass in 3 seconds:

{
    type = "cooking",
    output = "example:glass",
    recipe = "example:sand",
    cooktime = 3.0,
}

Fuel

A fuel recipe is an item associated with a "burning time" and an optional item replacement. There is no output. This is usually used as fuel for furnaces, ovens, stoves, etc.

Like with cooking recipes, the engine does not do anything specific with fuel recipes and it's up to games and mods to use them by retrieving them via core.get_craft_result.

Parameters:

• type = "fuel": Mandatory
• recipe: Itemname of the item to be used as fuel
• burntime: (optional) Burning time this item provides, in seconds. A floating-point number. (default: 1.0)
• replacements: Same meaning as for shaped recipes, but the mods that utilize fuels need to implement replacements on their own

Note: Games and mods are free to re-interpret the burntime in special cases, e.g. for an efficient furnace in which fuels burn twice as long.

Examples

Coal lump with a burntime of 20 seconds. Will be consumed when used.

{
    type = "fuel",
    recipe = "example:coal_lump",
    burntime = 20.0,
}

Lava bucket with a burn time of 60 seconds. Will become an empty bucket if used:

{
    type = "fuel",
    recipe = "example:lava_bucket",
    burntime = 60.0,
    replacements = {{"example:lava_bucket", "example:empty_bucket"}},
}

Ore definition

Used by core.register_ore.

See [Ores] section above for essential information.

{
    ore_type = "",
    -- Supported: "scatter", "sheet", "puff", "blob", "vein", "stratum"

    ore = "",
    -- Ore node to place

    ore_param2 = 0,
    -- Param2 to set for ore (e.g. facedir rotation)

    wherein = "",
    -- Node to place ore in. Multiple are possible by passing a list.

    clust_scarcity = 8 * 8 * 8,
    -- Ore has a 1 out of clust_scarcity chance of spawning in a node.
    -- If the desired average distance between ores is 'd', set this to
    -- d * d * d.

    clust_num_ores = 8,
    -- Number of ores in a cluster

    clust_size = 3,
    -- Size of the bounding box of the cluster.
    -- In this example, there is a 3 * 3 * 3 cluster where 8 out of the 27
    -- nodes are coal ore.

    y_min = -31000,
    y_max = 31000,
    -- Lower and upper limits for ore (inclusive)

    flags = "",
    -- Attributes for the ore generation, see 'Ore attributes' section above

    noise_threshold = 0,
    -- If noise is above this threshold, ore is placed. Not needed for a
    -- uniform distribution.

    noise_params = {
        offset = 0,
        scale = 1,
        spread = {x = 100, y = 100, z = 100},
        seed = 23,
        octaves = 3,
        persistence = 0.7
    },
    -- NoiseParams structure describing one of the perlin noises used for
    -- ore distribution.
    -- Needed by "sheet", "puff", "blob" and "vein" ores.
    -- Omit from "scatter" ore for a uniform ore distribution.
    -- Omit from "stratum" ore for a simple horizontal strata from y_min to
    -- y_max.

    biomes = {"desert", "rainforest"},
    -- List of biomes in which this ore occurs.
    -- Occurs in all biomes if this is omitted, and ignored if the Mapgen
    -- being used does not support biomes.
    -- Can be a list of (or a single) biome names, IDs, or definitions.

    -- Type-specific parameters

    -- "sheet"
    column_height_min = 1,
    column_height_max = 16,
    column_midpoint_factor = 0.5,

    -- "puff"
    np_puff_top = {
        offset = 4,
        scale = 2,
        spread = {x = 100, y = 100, z = 100},
        seed = 47,
        octaves = 3,
        persistence = 0.7
    },
    np_puff_bottom = {
        offset = 4,
        scale = 2,
        spread = {x = 100, y = 100, z = 100},
        seed = 11,
        octaves = 3,
        persistence = 0.7
    },

    -- "vein"
    random_factor = 1.0,

    -- "stratum"
    np_stratum_thickness = {
        offset = 8,
        scale = 4,
        spread = {x = 100, y = 100, z = 100},
        seed = 17,
        octaves = 3,
        persistence = 0.7
    },
    stratum_thickness = 8, -- only used if no noise defined
}

Biome definition

Used by core.register_biome.

The maximum number of biomes that can be used is 65535. However, using an excessive number of biomes will slow down map generation. Depending on desired performance and computing power the practical limit is much lower.

{
    name = "tundra",

    node_dust = "default:snow",
    -- Node dropped onto upper surface after all else is generated

    node_top = "default:dirt_with_snow",
    depth_top = 1,
    -- Node forming surface layer of biome and thickness of this layer

    node_filler = "default:permafrost",
    depth_filler = 3,
    -- Node forming lower layer of biome and thickness of this layer

    node_stone = "default:bluestone",
    -- Node that replaces all stone nodes between roughly y_min and y_max.

    node_water_top = "default:ice",
    depth_water_top = 10,
    -- Node forming a surface layer in seawater with the defined thickness

    node_water = "",
    -- Node that replaces all seawater nodes not in the surface layer

    node_river_water = "default:ice",
    -- Node that replaces river water in mapgens that use
    -- default:river_water

    node_riverbed = "default:gravel",
    depth_riverbed = 2,
    -- Node placed under river water and thickness of this layer

    node_cave_liquid = "default:lava_source",
    node_cave_liquid = {"default:water_source", "default:lava_source"},
    -- Nodes placed inside 50% of the medium size caves.
    -- Multiple nodes can be specified, each cave will use a randomly
    -- chosen node from the list.
    -- If this field is left out or 'nil', cave liquids fall back to
    -- classic behavior of lava and water distributed using 3D noise.
    -- For no cave liquid, specify "air".

    node_dungeon = "default:cobble",
    -- Node used for primary dungeon structure.
    -- If absent, dungeon nodes fall back to the 'mapgen_cobble' mapgen
    -- alias, if that is also absent, dungeon nodes fall back to the biome
    -- 'node_stone'.
    -- If present, the following two nodes are also used.

    node_dungeon_alt = "default:mossycobble",
    -- Node used for randomly-distributed alternative structure nodes.
    -- If alternative structure nodes are not wanted leave this absent.

    node_dungeon_stair = "stairs:stair_cobble",
    -- Node used for dungeon stairs.
    -- If absent, stairs fall back to 'node_dungeon'.

    y_max = 31000,
    y_min = 1,
    -- Upper and lower limits for biome.
    -- Alternatively you can use xyz limits as shown below.

    max_pos = {x = 31000, y = 128, z = 31000},
    min_pos = {x = -31000, y = 9, z = -31000},
    -- xyz limits for biome, an alternative to using 'y_min' and 'y_max'.
    -- Biome is limited to a cuboid defined by these positions.
    -- Any x, y or z field left undefined defaults to -31000 in 'min_pos' or
    -- 31000 in 'max_pos'.

    vertical_blend = 8,
    -- Vertical distance in nodes above 'y_max' over which the biome will
    -- blend with the biome above.
    -- Set to 0 for no vertical blend. Defaults to 0.

    heat_point = 0,
    humidity_point = 50,
    -- Characteristic temperature and humidity for the biome.
    -- These values create 'biome points' on a voronoi diagram with heat and
    -- humidity as axes. The resulting voronoi cells determine the
    -- distribution of the biomes.
    -- Heat and humidity have average values of 50, vary mostly between
    -- 0 and 100 but can exceed these values.

    weight = 1.0,
    -- Relative weight of the biome in the Voronoi diagram.
    -- A value of 0 (or less) is ignored and equivalent to 1.0.
}

Decoration definition

See [Decoration types]. Used by core.register_decoration.

{
    deco_type = "simple",
    -- Type. "simple", "schematic" or "lsystem" supported

    place_on = "default:dirt_with_grass",
    -- Node (or list of nodes) that the decoration can be placed on

    sidelen = 8,
    -- Size of the square (X / Z) divisions of the mapchunk being generated.
    -- Determines the resolution of noise variation if used.
    -- If the chunk size is not evenly divisible by sidelen, sidelen is made
    -- equal to the chunk size.

    fill_ratio = 0.02,
    -- The value determines 'decorations per surface node'.
    -- Used only if noise_params is not specified.
    -- If >= 10.0 complete coverage is enabled and decoration placement uses
    -- a different and much faster method.

    noise_params = {
        offset = 0,
        scale = 0.45,
        spread = {x = 100, y = 100, z = 100},
        seed = 354,
        octaves = 3,
        persistence = 0.7,
        lacunarity = 2.0,
        flags = "absvalue"
    },
    -- NoiseParams structure describing the perlin noise used for decoration
    -- distribution.
    -- A noise value is calculated for each square division and determines
    -- 'decorations per surface node' within each division.
    -- If the noise value >= 10.0 complete coverage is enabled and
    -- decoration placement uses a different and much faster method.

    biomes = {"Oceanside", "Hills", "Plains"},
    -- List of biomes in which this decoration occurs. Occurs in all biomes
    -- if this is omitted, and ignored if the Mapgen being used does not
    -- support biomes.
    -- Can be a list of (or a single) biome names, IDs, or definitions.

    y_min = -31000,
    y_max = 31000,
    -- Lower and upper limits for decoration (inclusive).
    -- These parameters refer to the Y coordinate of the 'place_on' node.

    spawn_by = "default:water",
    -- Node (or list of nodes) that the decoration only spawns next to.
    -- Checks the 8 neighboring nodes on the same height,
    -- and also the ones at the height plus the check_offset, excluding both center nodes.

    check_offset = -1,
    -- Specifies the offset that spawn_by should also check
    -- The default value of -1 is useful to e.g check for water next to the base node.
    -- 0 disables additional checks, valid values: {-1, 0, 1}

    num_spawn_by = 1,
    -- Number of spawn_by nodes that must be surrounding the decoration
    -- position to occur.
    -- If absent or -1, decorations occur next to any nodes.

    flags = "liquid_surface, force_placement, all_floors, all_ceilings",
    -- Flags for all decoration types.
    -- "liquid_surface": Find the highest liquid (not solid) surface under
    --   open air. Search stops and fails on the first solid node.
    --   Cannot be used with "all_floors" or "all_ceilings" below.
    -- "force_placement": Nodes other than "air" and "ignore" are replaced
    --   by the decoration.
    -- "all_floors", "all_ceilings": Instead of placement on the highest
    --   surface in a mapchunk the decoration is placed on all floor and/or
    --   ceiling surfaces, for example in caves and dungeons.
    --   Ceiling decorations act as an inversion of floor decorations so the
    --   effect of 'place_offset_y' is inverted.
    --   Y-slice probabilities do not function correctly for ceiling
    --   schematic decorations as the behavior is unchanged.
    --   If a single decoration registration has both flags the floor and
    --   ceiling decorations will be aligned vertically.

    ----- Simple-type parameters

    decoration = "default:grass",
    -- The node name used as the decoration.
    -- If instead a list of strings, a randomly selected node from the list
    -- is placed as the decoration.

    height = 1,
    -- Decoration height in nodes.
    -- If height_max is not 0, this is the lower limit of a randomly
    -- selected height.

    height_max = 0,
    -- Upper limit of the randomly selected height.
    -- If absent, the parameter 'height' is used as a constant.

    param2 = 0,
    -- Param2 value of decoration nodes.
    -- If param2_max is not 0, this is the lower limit of a randomly
    -- selected param2.

    param2_max = 0,
    -- Upper limit of the randomly selected param2.
    -- If absent, the parameter 'param2' is used as a constant.

    place_offset_y = 0,
    -- Y offset of the decoration base node relative to the standard base
    -- node position.
    -- Can be positive or negative. Default is 0.
    -- Effect is inverted for "all_ceilings" decorations.
    -- Ignored by 'y_min', 'y_max' and 'spawn_by' checks, which always refer
    -- to the 'place_on' node.

    ----- Schematic-type parameters

    schematic = "foobar.mts",
    -- If schematic is a string, it is the filepath relative to the current
    -- working directory of the specified Luanti schematic file.
    -- Could also be the ID of a previously registered schematic.

    schematic = {
        size = {x = 4, y = 6, z = 4},
        data = {
            {name = "default:cobble", param1 = 255, param2 = 0},
            {name = "default:dirt_with_grass", param1 = 255, param2 = 0},
            {name = "air", param1 = 255, param2 = 0},
              ...
        },
        yslice_prob = {
            {ypos = 2, prob = 128},
            {ypos = 5, prob = 64},
              ...
        },
    },
    -- Alternative schematic specification by supplying a table. The fields
    -- size and data are mandatory whereas yslice_prob is optional.
    -- See 'Schematic specifier' for details.

    replacements = {["oldname"] = "convert_to", ...},
    -- Map of node names to replace in the schematic after reading it.

    flags = "place_center_x, place_center_y, place_center_z",
    -- Flags for schematic decorations. See 'Schematic attributes'.

    rotation = "90",
    -- Rotation can be "0", "90", "180", "270", or "random"

    place_offset_y = 0,
    -- If the flag 'place_center_y' is set this parameter is ignored.
    -- Y offset of the schematic base node layer relative to the 'place_on'
    -- node.
    -- Can be positive or negative. Default is 0.
    -- Effect is inverted for "all_ceilings" decorations.
    -- Ignored by 'y_min', 'y_max' and 'spawn_by' checks, which always refer
    -- to the 'place_on' node.

    ----- L-system-type parameters

    treedef = {},
    -- Same as for `core.spawn_tree`.
    -- See section [L-system trees] for more details.
}

Chat command definition

Used by core.register_chatcommand.

Specifies the function to be called and the privileges required when a player issues the command. A help message that is the concatenation of the params and description fields is shown when the "/help" chatcommand is issued.

{
    params = "",
    -- Short parameter description.  See the below note.

    description = "",
    -- General description of the command's purpose.

    privs = {},
    -- Required privileges to run. See `core.check_player_privs()` for
    -- the format and see [Privileges] for an overview of privileges.

    func = function(name, param),
    -- Called when command is run.
    -- * `name` is the name of the player who issued the command.
    -- * `param` is a string with the full arguments to the command.
    -- Returns a boolean for success and a string value.
    -- The string is shown to the issuing player upon exit of `func` or,
    -- if `func` returns `false` and no string, the help message is shown.
}

Note that in params, the conventional use of symbols is as follows:

• <> signifies a placeholder to be replaced when the command is used. For example, when a player name is needed: <name>
• [] signifies param is optional and not required when the command is used. For example, if you require param1 but param2 is optional: <param1> [<param2>]
• | signifies exclusive or. The command requires one param from the options provided. For example: <param1> | <param2>
• () signifies grouping. For example, when param1 and param2 are both required, or only param3 is required: (<param1> <param2>) | <param3>

Example:

{
    params = "<name> <privilege>",

    description = "Remove privilege from player",

    privs = {privs=true},  -- Require the "privs" privilege to run

    func = function(name, param),
}

Privilege definition

Used by core.register_privilege.

{
    description = "",
    -- Privilege description

    give_to_singleplayer = true,
    -- Whether to grant the privilege to singleplayer.

    give_to_admin = true,
    -- Whether to grant the privilege to the server admin.
    -- Uses value of 'give_to_singleplayer' by default.

    on_grant = function(name, granter_name),
    -- Called when given to player 'name' by 'granter_name'.
    -- 'granter_name' will be nil if the priv was granted by a mod.

    on_revoke = function(name, revoker_name),
    -- Called when taken from player 'name' by 'revoker_name'.
    -- 'revoker_name' will be nil if the priv was revoked by a mod.

    -- Note that the above two callbacks will be called twice if a player is
    -- responsible, once with the player name, and then with a nil player
    -- name.
    -- Return true in the above callbacks to stop register_on_priv_grant or
    -- revoke being called.
}

Detached inventory callbacks

Used by core.create_detached_inventory.

{
    allow_move = function(inv, from_list, from_index, to_list, to_index, count, player),
    -- Called when a player wants to move items inside the inventory.
    -- Return value: number of items allowed to move.

    allow_put = function(inv, listname, index, stack, player),
    -- Called when a player wants to put something into the inventory.
    -- Return value: number of items allowed to put.
    -- Return value -1: Allow and don't modify item count in inventory.

    allow_take = function(inv, listname, index, stack, player),
    -- Called when a player wants to take something out of the inventory.
    -- Return value: number of items allowed to take.
    -- Return value -1: Allow and don't modify item count in inventory.

    on_move = function(inv, from_list, from_index, to_list, to_index, count, player),
    on_put = function(inv, listname, index, stack, player),
    on_take = function(inv, listname, index, stack, player),
    -- Called after the actual action has happened, according to what was
    -- allowed.
    -- No return value.
}

HUD Definition

Since most values have multiple different functions, please see the documentation in [HUD] section.

Used by ObjectRef:hud_add. Returned by ObjectRef:hud_get.

{
    type = "image",
    -- Type of element, can be "compass", "hotbar" (46 ¹), "image", "image_waypoint",
    -- "inventory", "minimap" (44 ¹), "statbar", "text" or "waypoint"
    -- ¹: minimal protocol version for client-side support
    -- If undefined "text" will be used.

    hud_elem_type = "image",
    -- Deprecated, same as `type`.
    -- In case both are specified `type` will be used.

    position = {x=0.5, y=0.5},
    -- Top left corner position of element

    name = "<name>",

    scale = {x = 1, y = 1},

    text = "<text>",

    text2 = "<text>",

    number = 0,

    item = 0,

    direction = 0,
    -- Direction: 0: left-right, 1: right-left, 2: top-bottom, 3: bottom-top

    alignment = {x=0, y=0},

    offset = {x=0, y=0},

    world_pos = {x=0, y=0, z=0},

    size = {x=0, y=0},

    z_index = 0,
    -- Z index: lower z-index HUDs are displayed behind higher z-index HUDs

    style = 0,
}

Particle definition

Used by core.add_particle.

{
    pos = {x=0, y=0, z=0},
    velocity = {x=0, y=0, z=0},
    acceleration = {x=0, y=0, z=0},
    -- Spawn particle at pos with velocity and acceleration

    expirationtime = 1,
    -- Disappears after expirationtime seconds

    size = 1,
    -- Scales the visual size of the particle texture.
    -- If `node` is set, size can be set to 0 to spawn a randomly-sized
    -- particle (just like actual node dig particles).

    collisiondetection = false,
    -- If true collides with `walkable` nodes and, depending on the
    -- `object_collision` field, objects too.

    collision_removal = false,
    -- If true particle is removed when it collides.
    -- Requires collisiondetection = true to have any effect.

    object_collision = false,
    -- If true particle collides with objects that are defined as
    -- `physical = true,` and `collide_with_objects = true,`.
    -- Requires collisiondetection = true to have any effect.

    vertical = false,
    -- If true faces player using y axis only

    texture = "image.png",
    -- The texture of the particle
    -- v5.6.0 and later: also supports the table format described in the
    -- following section, but due to a bug this did not take effect
    -- (beyond the texture name).
    -- v5.9.0 and later: fixes the bug.
    -- Note: "texture.animation" is ignored here. Use "animation" below instead.

    playername = "singleplayer",
    -- Optional, if specified spawns particle only on the player's client

    animation = {Tile Animation definition},
    -- Optional, specifies how to animate the particle texture

    glow = 0
    -- Optional, specify particle self-luminescence in darkness.
    -- Values 0-14.

    node = {name = "ignore", param2 = 0},
    -- Optional, if specified the particle will have the same appearance as
    -- node dig particles for the given node.
    -- `texture` and `animation` will be ignored if this is set.

    node_tile = 0,
    -- Optional, only valid in combination with `node`
    -- If set to a valid number 1-6, specifies the tile from which the
    -- particle texture is picked.
    -- Otherwise, the default behavior is used. (currently: any random tile)

    drag = {x=0, y=0, z=0},
    -- v5.6.0 and later: Optional drag value, consult the following section
    -- Note: Only a vector is supported here. Alternative forms like a single
    -- number are not supported.

    jitter = {min = ..., max = ..., bias = 0},
    -- v5.6.0 and later: Optional jitter range, consult the following section

    bounce = {min = ..., max = ..., bias = 0},
    -- v5.6.0 and later: Optional bounce range, consult the following section
}

ParticleSpawner definition

Used by core.add_particlespawner.

Before v5.6.0, particlespawners used a different syntax and had a more limited set of features. Definition fields that are the same in both legacy and modern versions are shown in the next listing, and the fields that are used by legacy versions are shown separated by a comment; the modern fields are too complex to compactly describe in this manner and are documented after the listing.

The older syntax can be used in combination with the newer syntax (e.g. having minpos, maxpos, and pos all set) to support older servers. On newer servers, the new syntax will override the older syntax; on older servers, the newer syntax will be ignored.

{
    -------------------
    -- Common fields --
    -------------------
    -- (same name and meaning in both new and legacy syntax)

    amount = 1,
    -- Number of particles spawned over the time period `time`.

    time = 1,
    -- Lifespan of spawner in seconds.
    -- If time is 0 spawner has infinite lifespan and spawns the `amount` on
    -- a per-second basis.

    collisiondetection = false,
    -- If true collide with `walkable` nodes and, depending on the
    -- `object_collision` field, objects too.

    collision_removal = false,
    -- If true particles are removed when they collide.
    -- Requires collisiondetection = true to have any effect.

    object_collision = false,
    -- If true particles collide with objects that are defined as
    -- `physical = true,` and `collide_with_objects = true,`.
    -- Requires collisiondetection = true to have any effect.

    attached = ObjectRef,
    -- If defined, particle positions, velocities and accelerations are
    -- relative to this object's position and yaw

    vertical = false,
    -- If true face player using y axis only

    texture = "image.png",
    -- The texture of the particle
    -- v5.6.0 and later: also supports the table format described in the
    -- following section.

    playername = "singleplayer",
    -- Optional, if specified spawns particles only on the player's client

    animation = {Tile Animation definition},
    -- Optional, specifies how to animate the particles' texture
    -- v5.6.0 and later: set length to -1 to synchronize the length
    -- of the animation with the expiration time of individual particles.
    -- (-2 causes the animation to be played twice, and so on)

    glow = 0,
    -- Optional, specify particle self-luminescence in darkness.
    -- Values 0-14.

    node = {name = "ignore", param2 = 0},
    -- Optional, if specified the particles will have the same appearance as
    -- node dig particles for the given node.
    -- `texture` and `animation` will be ignored if this is set.

    node_tile = 0,
    -- Optional, only valid in combination with `node`
    -- If set to a valid number 1-6, specifies the tile from which the
    -- particle texture is picked.
    -- Otherwise, the default behavior is used. (currently: any random tile)

    -------------------
    -- Legacy fields --
    -------------------

    minpos = {x=0, y=0, z=0},
    maxpos = {x=0, y=0, z=0},
    minvel = {x=0, y=0, z=0},
    maxvel = {x=0, y=0, z=0},
    minacc = {x=0, y=0, z=0},
    maxacc = {x=0, y=0, z=0},
    minexptime = 1,
    maxexptime = 1,
    minsize = 1,
    maxsize = 1,
    -- The particles' properties are random values between the min and max
    -- values.
    -- applies to: pos, velocity, acceleration, expirationtime, size
    -- If `node` is set, min and maxsize can be set to 0 to spawn
    -- randomly-sized particles (just like actual node dig particles).
}

Modern definition fields

After v5.6.0, spawner properties can be defined in several different ways depending on the level of control you need. pos for instance can be set as a single vector, in which case all particles will appear at that exact point throughout the lifetime of the spawner. Alternately, it can be specified as a min-max pair, specifying a cubic range the particles can appear randomly within. Finally, some properties can be animated by suffixing their key with _tween (e.g. pos_tween) and supplying a tween table.

The following definitions are all equivalent, listed in order of precedence from lowest (the legacy syntax) to highest (tween tables). If multiple forms of a property definition are present, the highest-precedence form will be selected and all lower-precedence fields will be ignored, allowing for graceful degradation in older clients).

{
  -- old syntax
  maxpos = {x = 0, y = 0, z = 0},
  minpos = {x = 0, y = 0, z = 0},

  -- absolute value
  pos = 0,
  -- all components of every particle's position vector will be set to this
  -- value

  -- vec3
  pos = vector.new(0,0,0),
  -- all particles will appear at this exact position throughout the lifetime
  -- of the particlespawner

  -- vec3 range
  pos = {
        -- the particle will appear at a position that is picked at random from
        -- within a cubic range

        min = vector.new(0,0,0),
        -- `min` is the minimum value this property will be set to in particles
        -- spawned by the generator

        max = vector.new(0,0,0),
        -- `max` is the minimum value this property will be set to in particles
        -- spawned by the generator

        bias = 0,
        -- when `bias` is 0, all random values are exactly as likely as any
        -- other. when it is positive, the higher it is, the more likely values
        -- will appear towards the minimum end of the allowed spectrum. when
        -- it is negative, the lower it is, the more likely values will appear
        -- towards the maximum end of the allowed spectrum. the curve is
        -- exponential and there is no particular maximum or minimum value
    },

    -- tween table
    pos_tween = {...},
    -- a tween table should consist of a list of frames in the same form as the
    -- untweened pos property above, which the engine will interpolate between,
    -- and optionally a number of properties that control how the interpolation
    -- takes place. currently **only two frames**, the first and the last, are
    -- used, but extra frames are accepted for the sake of forward compatibility.
    -- any of the above definition styles can be used here as well in any combination
    -- supported by the property type

    pos_tween = {
        style = "fwd",
        -- linear animation from first to last frame (default)
        style = "rev",
        -- linear animation from last to first frame
        style = "pulse",
        -- linear animation from first to last then back to first again
        style = "flicker",
        -- like "pulse", but slightly randomized to add a bit of stutter

        reps = 1,
        -- number of times the animation is played over the particle's lifespan

        start = 0.0,
        -- point in the spawner's lifespan at which the animation begins. 0 is
        -- the very beginning, 1 is the very end

        -- frames can be defined in a number of different ways, depending on the
        -- underlying type of the property. for now, all but the first and last
        -- frame are ignored

        -- frames

            -- floats
            0, 0,

            -- vec3s
            vector.new(0,0,0),
            vector.new(0,0,0),

            -- vec3 ranges
            { min = vector.new(0,0,0), max = vector.new(0,0,0), bias = 0 },
            { min = vector.new(0,0,0), max = vector.new(0,0,0), bias = 0 },

            -- mixed
            0, { min = vector.new(0,0,0), max = vector.new(0,0,0), bias = 0 },
    },
}

All of the properties that can be defined in this way are listed in the next section, along with the datatypes they accept.

List of particlespawner properties

All properties in this list of type "vec3 range", "float range" or "vec3" can be animated with *_tween tables. For example, jitter can be tweened by setting a jitter_tween table instead of (or in addition to) a jitter table/value.

In this section, a float range is a table defined as so: { min = A, max = B } A and B are your supplemented values. For a vec3 range this means they are vectors. Types used are defined in the previous section.

• vec3 range pos: the position at which particles can appear

• vec3 range vel: the initial velocity of the particle

• vec3 range acc: the direction and speed with which the particle accelerates

• float range size: scales the visual size of the particle texture. if node is set, this can be set to 0 to spawn randomly-sized particles (just like actual node dig particles).

• vec3 range jitter: offsets the velocity of each particle by a random amount within the specified range each frame. used to create Brownian motion.

• vec3 range drag: the amount by which absolute particle velocity along each axis is decreased per second. a value of 1.0 means that the particle will be slowed to a stop over the space of a second; a value of -1.0 means that the particle speed will be doubled every second. to avoid interfering with gravity provided by acc, a drag vector like vector.new(1,0,1) can be used instead of a uniform value.

• float range bounce: how bouncy the particles are when collisiondetection is turned on. values less than or equal to 0 turn off particle bounce; 1 makes the particles bounce without losing any velocity, and 2 makes them double their velocity with every bounce. bounce is not bounded but values much larger than 1.0 probably aren't very useful.

• float range exptime: the number of seconds after which the particle disappears.

• table attract: sets the birth orientation of particles relative to various shapes defined in world coordinate space. this is an alternative means of setting the velocity which allows particles to emerge from or enter into some entity or node on the map, rather than simply being assigned random velocity values within a range. the velocity calculated by this method will be added to that specified by vel if vel is also set, so in most cases vel should be set to 0. attract has the fields:

  • string kind: selects the kind of shape towards which the particles will be oriented. it must have one of the following values:

  • "none": no attractor is set and the attractor table is ignored

  • "point": the particles are attracted to a specific point in space. use this also if you want a sphere-like effect, in combination with the radius property.

  • "line": the particles are attracted to an (infinite) line passing through the points origin and angle. use this for e.g. beacon effects, energy beam effects, etc.

  • "plane": the particles are attracted to an (infinite) plane on whose surface origin designates a point in world coordinate space. use this for e.g. particles entering or emerging from a portal.

  • float range strength: the speed with which particles will move towards attractor. If negative, the particles will instead move away from that point.

  • vec3 origin: the origin point of the shape towards which particles will initially be oriented. functions as an offset if origin_attached is also set.

  • vec3 direction: sets the direction in which the attractor shape faces. for lines, this sets the angle of the line; e.g. a vector of (0,1,0) will create a vertical line that passes through origin. for planes, direction is the surface normal of an infinite plane on whose surface origin is a point. functions as an offset if direction_attached is also set.

  • ObjectRef origin_attached: allows the origin to be specified as an offset from the position of an entity rather than a coordinate in world space.

  • ObjectRef direction_attached: allows the direction to be specified as an offset from the position of an entity rather than a coordinate in world space.

  • bool die_on_contact: if true, the particles' lifetimes are adjusted so that they will die as they cross the attractor threshold. this behavior is the default but is undesirable for some kinds of animations; set it to false to allow particles to live out their natural lives.

• vec3 range radius: if set, particles will be arranged in a sphere around pos. A constant can be used to create a spherical shell of particles, a vector to create an ovoid shell, and a range to create a volume; e.g. {min = 0.5, max = 1, bias = 1} will allow particles to appear between 0.5 and 1 nodes away from pos but will cluster them towards the center of the sphere. Usually if radius is used, pos should be a single point, but it can still be a range if you really know what you're doing (e.g. to create a "roundcube" emitter volume).

Textures

In versions before v5.6.0, particle/particlespawner textures could only be specified as a single texture string. After v5.6.0, textures can now be specified as a table as well. This table contains options that allow simple animations to be applied to the texture.

texture = {
    name = "mymod_particle_texture.png",
    -- the texture specification string

    alpha = 1.0,
    -- controls how visible the particle is; at 1.0 the particle is fully
    -- visible, at 0, it is completely invisible.

    alpha_tween = {1, 0},
    -- can be used instead of `alpha` to animate the alpha value over the
    -- particle's lifetime. these tween tables work identically to the tween
    -- tables used in particlespawner properties, except that time references
    -- are understood with respect to the particle's lifetime, not the
    -- spawner's. {1,0} fades the particle out over its lifetime.

    scale = 1,
    scale = {x = 1, y = 1},
    -- scales the texture onscreen

    scale_tween = {
        {x = 1, y = 1},
        {x = 0, y = 1},
    },
    -- animates the scale over the particle's lifetime. works like the
    -- alpha_tween table, but can accept two-dimensional vectors as well as
    -- integer values. the example value would cause the particle to shrink
    -- in one dimension over the course of its life until it disappears

    blend = "alpha",
    -- (default) blends transparent pixels with those they are drawn atop
    -- according to the alpha channel of the source texture. useful for
    -- e.g. material objects like rocks, dirt, smoke, or node chunks
    -- note: there will be rendering bugs when particles interact with
    -- translucent nodes. particles are also not transparency-sorted
    -- relative to each other.
    blend = "clip",
    -- pixels are either fully opaque or fully transparent,
    -- depending on whether alpha is greater than or less than 50%
    -- (just like `use_texture_alpha = "clip"` for nodes).
    -- you should prefer this if you don't need semi-transparency, as it's faster.
    blend = "add",
    -- adds the value of pixels to those underneath them, modulo the sources
    -- alpha channel. useful for e.g. bright light effects like sparks or fire
    blend = "screen",
    -- like "add" but less bright. useful for subtler light effects. note that
    -- this is NOT formally equivalent to the "screen" effect used in image
    -- editors and compositors, as it does not respect the alpha channel of
    -- of the image being blended
    blend = "sub",
    -- the inverse of "add"; the value of the source pixel is subtracted from
    -- the pixel underneath it. a white pixel will turn whatever is underneath
    -- it black; a black pixel will be "transparent". useful for creating
    -- darkening effects

    animation = {Tile Animation definition},
    -- overrides the particlespawner's global animation property for a single
    -- specific texture
}

For particlespawners, it is also possible to set the texpool property instead of a single texture definition. A texpool consists of a list of possible particle textures. Every time a particle is spawned, the engine will pick a texture at random from the texpool and assign it as that particle's texture. You can also specify a texture in addition to a texpool; the texture value will be ignored on newer clients but will be sent to older (pre-v5.6.0) clients that do not implement texpools.

texpool = {
    "mymod_particle_texture.png";
    { name = "mymod_spark.png", alpha_tween = {1, 0} },
    {
      name = "mymod_dust.png",
      alpha = 0.3,
      scale = 1.5,
      animation = {
            type = "vertical_frames",
            aspect_w = 16, aspect_h = 16,

            length = 3,
            -- the animation lasts for 3s and then repeats
            length = -3,
            -- repeat the animation three times over the particle's lifetime
            -- (post-v5.6.0 clients only)
      },
    },
}

List of animatable texture properties

While animated particlespawner values vary over the course of the particlespawner's lifetime, animated texture properties vary over the lifespans of the individual particles spawned with that texture. So a particle with the texture property

alpha_tween = {
    0.0, 1.0,
    style = "pulse",
    reps = 4,
}

would be invisible at its spawning, pulse visible four times throughout its lifespan, and then vanish again before expiring.

• float alpha (0.0 - 1.0): controls the visibility of the texture
• vec2 scale: controls the size of the displayed billboard onscreen. Its units are multiples of the parent particle's assigned size (see the size property above)

HTTPRequest definition

Used by HTTPApiTable.fetch and HTTPApiTable.fetch_async.

{
    url = "http://example.org",

    timeout = 10,
    -- Timeout for request to be completed in seconds. Default depends on engine settings.

    method = "GET", "POST", "PUT" or "DELETE"
    -- The http method to use. Defaults to "GET".

    data = "Raw request data string" OR {field1 = "data1", field2 = "data2"},
    -- Data for the POST, PUT or DELETE request.
    -- Accepts both a string and a table. If a table is specified, encodes
    -- table as x-www-form-urlencoded key-value pairs.

    user_agent = "ExampleUserAgent",
    -- Optional, if specified replaces the default Luanti user agent with
    -- given string

    extra_headers = { "Accept-Language: en-us", "Accept-Charset: utf-8" },
    -- Optional, if specified adds additional headers to the HTTP request.
    -- You must make sure that the header strings follow HTTP specification
    -- ("Key: Value").

    multipart = boolean
    -- Optional, if true performs a multipart HTTP request.
    -- Default is false.
    -- Post only, data must be array

    post_data = "Raw POST request data string" OR {field1 = "data1", field2 = "data2"},
    -- Deprecated, use `data` instead. Forces `method = "POST"`.
}

HTTPRequestResult definition

Passed to HTTPApiTable.fetch callback. Returned by HTTPApiTable.fetch_async_get.

{
    completed = true,
    -- If true, the request has finished (either succeeded, failed or timed
    -- out)

    succeeded = true,
    -- If true, the request was successful

    timeout = false,
    -- If true, the request timed out

    code = 200,
    -- HTTP status code

    data = "response"
}

Authentication handler definition

Used by core.register_authentication_handler.

{
    get_auth = function(name),
    -- Get authentication data for existing player `name` (`nil` if player
    -- doesn't exist).
    -- Returns following structure:
    -- `{password=<string>, privileges=<table>, last_login=<number or nil>}`

    create_auth = function(name, password),
    -- Create new auth data for player `name`.
    -- Note that `password` is not plain-text but an arbitrary
    -- representation decided by the engine.

    delete_auth = function(name),
    -- Delete auth data of player `name`.
    -- Returns boolean indicating success (false if player is nonexistent).

    set_password = function(name, password),
    -- Set password of player `name` to `password`.
    -- Auth data should be created if not present.

    set_privileges = function(name, privileges),
    -- Set privileges of player `name`.
    -- `privileges` is in table form: keys are privilege names, values are `true`;
    -- auth data should be created if not present.

    reload = function(),
    -- Reload authentication data from the storage location.
    -- Returns boolean indicating success.

    record_login = function(name),
    -- Called when player joins, used for keeping track of last_login

    iterate = function(),
    -- Returns an iterator (use with `for` loops) for all player names
    -- currently in the auth database
}

Bit Library

Functions: bit.tobit, bit.tohex, bit.bnot, bit.band, bit.bor, bit.bxor, bit.lshift, bit.rshift, bit.arshift, bit.rol, bit.ror, bit.bswap

See http://bitop.luajit.org/ for advanced information.

Tracy Profiler

Luanti can be built with support for the Tracy profiler, which can also be useful for profiling mods and is exposed to Lua as the global tracy.

See doc/developing/misc.md for details.

Note: This is a development feature and not covered by compatibility promises.

Error Handling

When an error occurs that is not caught, Luanti calls the function core.error_handler with the error object as its first argument. The second argument is the stack level where the error occurred. The return value is the error string that should be shown. By default this is a backtrace from debug.traceback. If the error object is not a string, it is first converted with tostring before being displayed. This means that you can use tables as error objects so long as you give them __tostring metamethods.

You can override core.error_handler. You should call the previous handler with the correct stack level in your implementation.