minetest-mm/mods/rubiks/init.lua

--Okay, so we're making a Rubik's Cube!
--Let's start with the basics.
local colors = {
	'green',  -- +Y
	'blue',   -- -Y
	'red',    -- +X
	'orange', -- -X
	'white',  -- +Z
	'yellow', -- -Z
}

local materials = {} --what you craft the spawner with
local tiles = {} --Base colors
local spawntex = {} --what is on the spawner
local cubetex = {} --what is on the cubelets
for color = 1, #colors do
	materials[color] = 'wool:'..colors[color]
	tiles[color] = 'wool_'..colors[color]..'.png'
	spawntex[color] = tiles[color]..'^rubiks_three.png'
	cubetex[color] = tiles[color]..'^rubiks_outline.png'
end

--is this the center of a face, on the edge, or is it a corner?
local function get_axesoff(pos)
	axesoff = 0
	dir = {x=0, y=0, z=0}
	center = {unpack(pos)}
	local meta = minetest.env:get_meta(pos)
	local string = meta:get_string('cube_center')
	if string ~= nil then
		center = minetest.string_to_pos(string)
		if center ~= nil then
			dir = {x=pos.x-center.x, y=pos.y-center.y, z=pos.z-center.z}
			axesoff = (dir.x ~= 0 and 1 or 0)
			+ (dir.y ~= 0 and 1 or 0)
			+ (dir.z ~= 0 and 1 or 0)
		end
	end
	return axesoff, dir, center
end

--this isn't in the cubelets' on_construct
--because the meta already needs to be set
local function set_cubelet_formspec(pos, size)
	axesoff, dir, center = get_axesoff(pos)
	if axesoff == 1 then
		local meta = minetest.env:get_meta(pos)
		meta:set_string("formspec",
			"size["..size..","..size.."]"..
			
			"image_button_exit[0,0;1,1;"..minetest.inventorycube(
				tiles[1]..'^rubiks_four.png',
				tiles[6]..'^rubiks_four.png',
				tiles[3]..'^rubiks_four.png')..
			";larger;]"..

			"image_button_exit[0,1;1,1;"..minetest.inventorycube(
				spawntex[1],
				spawntex[6],
				spawntex[3])..
			";reset;]"..

			--"image_button_exit[0,2;1,1;rubiks_scramble.png;scramble;]"..
			"image_button_exit[0,2;1,1;"..minetest.inventorycube(
				tiles[1]..'^rubiks_two.png',
				tiles[6]..'^rubiks_two.png',
				tiles[3]..'^rubiks_two.png')..
			";smaller;]"..

			"image_button_exit[1,0;1,1;"..minetest.inventorycube(
				spawntex[1],
				spawntex[4],
				spawntex[6])..
			";L3;]"..

			"image_button_exit[1,1;1,1;"..minetest.inventorycube(
				spawntex[1],
				tiles[6]..'^rubiks_with_orange.png^rubiks_three.png',
				tiles[3]..'^rubiks_with_yellow.png^rubiks_three.png')..
			";L1;]"..

			"image_button_exit[1,2;1,1;"..minetest.inventorycube(
				spawntex[1],
				tiles[6]..'^rubiks_with_orange.png^rubiks_three.png^[transformR180',
				tiles[3]..'^rubiks_with_yellow.png^rubiks_three.png^[transformR180')..
			";L2;]"..
			
			"image_button_exit[2,0;1,1;"..minetest.inventorycube(
				spawntex[1],
				spawntex[3],
				spawntex[5])..
			";R3;]"..

			"image_button_exit[2,1;1,1;"..minetest.inventorycube(
				spawntex[1],
				tiles[6]..'^rubiks_with_red.png^rubiks_three.png',
				tiles[3]..'^rubiks_with_white.png^rubiks_three.png')..
			";R1;]"..

			"image_button_exit[2,2;1,1;"..minetest.inventorycube(
				spawntex[1],
				tiles[6]..'^rubiks_with_red.png^rubiks_three.png^[transformR180',
				tiles[3]..'^rubiks_with_white.png^rubiks_three.png^[transformR180')..
				";R2;]"..
		'')
	end
end

local function expand_cube(pos, spawn)
	for x = pos.x-1, pos.x+1 do
	for y = pos.y-1, pos.y+1 do
	for z = pos.z-1, pos.z+1 do
	pos2 = {x=x, y=y, z=z}
		if spawn then --create
			--don't overwrite the spawner
			if not(pos2.x==pos.x and pos2.y==pos.y and pos2.z==pos.z) then
				--always starts the same direction
				name = 'rubiks:cubelet'
				minetest.env:add_node(pos2, {name = name})
				--keep track of center for the purpose of rotating the cube
				local meta = minetest.env:get_meta(pos2)
				meta:set_string('cube_center',
					minetest.pos_to_string(pos)
				)
				set_cubelet_formspec(pos2, 3)
			end
		else --delete
			minetest.env:remove_node(pos2)
		end
	end
	end
	end
	if create then
		--keep a record so you can't get two cubes from one, or something like that
		local meta = minetest.env:get_meta(pos)
		meta:set_int('has_spawned', 1)
	end
end

--can't make a rubik's cube without the cube
minetest.register_node('rubiks:cube', {
	--spawner because I don't get the uv pos yet
	description  = "Rubik's Cube",
	tiles = spawntex,
	--show green, yellow, red sides to look 3d in inventory
	inventory_image = minetest.inventorycube(spawntex[1], spawntex[6], spawntex[3]),
	--want it to be diggable, quickly
	groups = {crumbly=3},
	on_punch = function(pos, node, puncher)
		for x = pos.x-1, pos.x+1 do
		for y = pos.y-1, pos.y+1 do
		for z = pos.z-1, pos.z+1 do
			if not(pos.x==x and pos.y==y and pos.z==z) then
				if minetest.env:get_node({x=x, y=y, z=z}).name ~= 'air' then
					--put it on a pedestal then remove the pedestal
					minetest.chat_send_player(puncher:get_player_name(), "Clear some space for Rubik's cube to expand")
					return
				end
			end
		end
		end
		end
		--surrounded by air, so
		expand_cube(pos, true)
	end,
	can_dig = function(pos, digger)
		--digging the center of a spawned cube yields
		--an extra cube without this - don't cheat when flying
		local meta = minetest.env:get_meta(pos)
		if meta:get_int('has_spawned') == 1 then
			return false
		end
		return true
	end,

})

--100% wool, need a way to get wool now.
minetest.register_craft({
	type = "shapeless",
	output = "rubiks:cube",
	recipe = materials,
})

local function rotate_cube(pos, dir, clockwise, layer)
	--save cube to rotate without losing data
	cube = {}
	for x = -1, 1 do cube[x] = {}
	for y = -1, 1 do cube[x][y] = {}
	for z = -1, 1 do
		--read absolute position, save relative position
		pos2 = {x=pos.x+x, y=pos.y+y, z=pos.z+z}
		cube[x][y][z] = {
			node = minetest.env:get_node(pos2),
			meta = minetest.env:get_meta(pos2):to_table()
		}
	end
	end
	end

	--what side of the cube will be rotated on what axes
	loadpos, axes = {0, 0, 0}, {}
	if dir.x ~= 0 then
		loadpos[1] = dir.x
		for l=1, layer-1 do
			loadpos[1] = loadpos[1] - dir.x
		end
		axes[1] = 3--z
		axes[2] = 2--y
	end
	if dir.y ~= 0 then
		loadpos[2] = dir.y
		for l=1, layer-1 do
			loadpos[2] = loadpos[2] - dir.y
		end
		axes[1] = 1--x
		axes[2] = 3--z

	end
	if dir.z ~= 0 then
		loadpos[3] = dir.z
		for l=1, layer-1 do
			loadpos[3] = loadpos[3] - dir.z
		end
		axes[1] = 2--y
		axes[2] = 1--x
	end

	sign = true
	if dir.x == -1 or dir.y == -1 or dir.z == -1 then
		clockwise = not clockwise
		--still clockwise, just from the opposite perspective
		sign = false
	end

	--start rotating
	for firstaxis = -1, 1 do loadpos[axes[1]] = firstaxis
	for secondaxis = -1, 1 do loadpos[axes[2]] = secondaxis

		--don't lose data here either
		writepos = {unpack(loadpos)}

		--rotate around center of face
		writepos[axes[1]] = loadpos[axes[2]] * (clockwise and 1 or -1)
		writepos[axes[2]] = loadpos[axes[1]] * (clockwise and -1 or 1)

		--get absolute position
		pos2 = {x=pos.x+writepos[1], y=pos.y+writepos[2], z=pos.z+writepos[3]}

		--rotate cubelet itself
		loadcubelet = cube[loadpos[1]][loadpos[2]][loadpos[3]]
		name = loadcubelet.node.name
		if name ~= 'rubiks:cube' then--continue end
			--turnaxis = dir.x and 1 or dir.y and 2 or dir.z and 3
			    if dir.x ~= 0 then turnaxis = 1
			elseif dir.y ~= 0 then turnaxis = 2
			else turnaxis = 3 end
			--print(minetest.registered_nodes['rubiks:cubelet'].tiles[getface(loadcubelet.node.param2, turnaxis, negative)])
			--place it
			minetest.env:add_node(pos2, {name = name, param2 =
				axisRotate(loadcubelet.node.param2, turnaxis, clockwise and 90 or -90)
			})
			--
			--print(colors[getface(loadcubelet.node.param2, turnaxis, sign)])
			--
			local meta = minetest.env:get_meta(pos2)
			meta:from_table(loadcubelet.meta)
		end
	end
	end
end

local function start_rotation(pos, clockwise, layer)
	axesoff, dir, center = get_axesoff(pos)
	if axesoff == 1 then --center
		if layer == 6 then
			for layer = 1, 3 do
				rotate_cube(center, dir, clockwise, layer)
			end
		else
			rotate_cube(center, dir, clockwise, layer)
		end
	elseif axesoff == 2 then --edge

	else --corner

	end
end

local function register_cubelets()
	minetest.register_node('rubiks:cubelet', {
		description = "Rubik's Cubelet",
		tiles = cubetex,
		inventory_image = minetest.inventorycube(cubetex[1], cubetex[6], cubetex[3]),
		groups = {crumbly=2, not_in_creative_inventory = 1},
		after_dig_node = function(pos, oldnode, oldmeta, digger)
			local string = oldmeta.fields.cube_center
			if string ~= nil then
				pos = minetest.string_to_pos(string)
				expand_cube(pos, false)
			end
		end,
		drop = 'rubiks:cube',
		on_punch = function(pos, node, puncher)
			start_rotation(pos, true, 1)
		end,
		--cubelets not in the center of the face never get formspecs
		on_receive_fields = function(pos, formname, fields, sender)
			if fields.L1 then
				start_rotation(pos, false, 1)
			elseif fields.L2 then
				start_rotation(pos, false, 3)
			elseif fields.L3 then
				start_rotation(pos, false, 6)
			elseif fields.R1 then
				start_rotation(pos, true, 1)
			elseif fields.R2 then
				start_rotation(pos, true, 3)
			elseif fields.R3 then
				start_rotation(pos, true, 6)
			elseif fields.larger then
				minetest.chat_send_player(sender:get_player_name(),
					'TODO: make the cube have more layers'
				)
			elseif fields.smaller then
				minetest.chat_send_player(sender:get_player_name(),
					'TODO: make the cube have less layers'
				)
			else --reset
				minetest.chat_send_player(sender:get_player_name(),
					'TODO: toggle between reset/scramble'
				)
			end
		end,
		paramtype2 = 'facedir',
	})
end register_cubelets()

--temporary aliases to update cleanly
for rotations = 1, 6 do
	minetest.register_alias('rubiks:cubelet'..rotations, 'rubiks:cubelet')
end

--Stealable Code
--You may edit this for coding style
--Do not use this in your mod. This is for sharing only.
--Put this somewhere where all modders can get to it
-------------------------------------------------------------------------------

function axisRotate(facedir, turnaxis, turnrot)
	turnrot = math.floor(turnrot / 90) % 4
	axis = math.floor(facedir / 4)
	rot = facedir % 4
	    if turnaxis == 1 then --x
		if 3 == axis or axis == 4 then
			if axis == 4 then turnrot = -turnrot end
			rot = (rot + turnrot) % 4
		else
			for r = 0, turnrot-1 do
				    if axis == 0 then	axis = 1
				elseif axis == 1 then	axis = 5
							rot=(rot+2)%4
				elseif axis == 5 then	axis = 2
							rot=(rot-2)%4
				elseif axis == 2 then	axis = 0
				else
					error("axisRotate: my bad")
				end
			end
		end
	elseif turnaxis == 2 then --y
		if 0 == axis or axis == 5 then
			if axis == 5 then turnrot = -turnrot end
			rot = (rot + turnrot) % 4
		else
			for r = 0, turnrot-1 do
				    if axis == 1 then	axis = 3
				elseif axis == 3 then	axis = 2
				elseif axis == 2 then	axis = 4
				elseif axis == 4 then	axis = 1
				else
					error("axisRotate: my bad")
				end	rot = (rot + 1) % 4
			end
		end
	elseif turnaxis == 3 then --z
		if 1 == axis or axis == 2 then
			if axis == 2 then turnrot = -turnrot end
			rot = (rot + turnrot) % 4
		else
			for r = 0, turnrot-1 do
				    if axis == 0 then	axis = 4
				elseif axis == 4 then	axis = 5
				elseif axis == 5 then	axis = 3
				elseif axis == 3 then	axis = 0
				else
					error("axisRotate: my bad")
				end
			end
		end
	else
		error("axisRotate: turnaxis not 1-3")
	end
	facedir = axis * 4 + rot
	return facedir
end
local function rotfaces(faces, turnaxis, turnrot)
	turnrot = turnrot % 4 
	for r = 0, turnrot-1 do
		    if turnaxis == 1 then --x
			torot = {1, 5, 2, 6}
		elseif turnaxis == 2 then --y
			torot = {6, 4, 5, 3}
		elseif turnaxis == 3 then --z
			torot = {1, 4, 2, 3}
		else
			error("rotfaces: turnaxis: my bad")
		end
		     wraparound = faces[torot[3]]
		faces[torot[3]] = faces[torot[2]]
		faces[torot[2]] = faces[torot[1]]
		faces[torot[1]] = wraparound
	end
	return faces
end

function getfaces(facedir)
	--FIXME?
	--tiles		±Y±X±Z
	--facedir axes	+Y±Z±X-Y
	
	axis = math.floor(facedir / 4)
	rot = facedir % 4

	--      +Y -Y +X -X +Z -Z
	faces = {1, 2, 3, 4, 5, 6}
	    if axis == 0 then -- +Y
		turnaxis = 2
	elseif axis == 1 then -- +Z
		faces = rotfaces(faces, 1, 1) -- +X
		turnaxis = 3
	elseif axis == 2 then -- -Z
		faces = rotfaces(faces, 1, -1) -- -X
		turnaxis = 3
		rot = -rot
	elseif axis == 3 then -- +X
		faces = rotfaces(faces, 3, -1) -- -Z
		turnaxis = 1
	elseif axis == 4 then -- -X
		faces = rotfaces(faces, 3, 1) -- +Z
		turnaxis = 1
		rot = -rot
	elseif axis == 5 then -- -Y
		faces = rotfaces(faces, 3, 2)-- ±Z
		turnaxis = 2
		rot = -rot
	else
		error("getfaces: bad facedir: "..facedir..' '..axis..' '..rot)
	end
	return rotfaces(faces, turnaxis, rot)
end

function getface(facedir, axis, sign)
	faces = getfaces(facedir)
	return faces[
		axis == 1 and (sign and 3 or 4) or (
			axis == 2 and (sign and 1 or 2) or (
				axis == 3 and (sign and 5 or 6)
			)
		)
	]
end