musttest_game/mods/ingots/api.lua

--[[
	Ingots - allows the placemant of ingots in the world
	Copyright (C) 2018  Skamiz Kazzarch

	This library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Lesser General Public
	License as published by the Free Software Foundation; either
	version 2.1 of the License, or (at your option) any later version.

	This library is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public
	License along with this library; if not, write to the Free Software
	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
]]--

-- takes an item name and a texture name and a boolean whether the ingots are big
function ingots.register_ingots(ingot_item, texture, is_big)

	--checks, whether the item name is a valid item (thanks 'puzzlecube')
	if not minetest.registered_items[ingot_item] then
		minetest.log("warning", ingot_item.." is not registered. Skipping ingot registration")
		return
	end

	-- de hardcoded modname, which allows the api to be properly used from within other mods (thanks 'argyle')
	local mod_name = minetest.get_current_modname()
	local mod_prefix = mod_name .. ":"

	local stack_size = 64
	local texture_prefix = "ingot_"
	--gets item name witout mod part, to be used in the deffinition of the new nodes
	local ingot_name = string.sub(ingot_item, string.find(ingot_item, ":", 1, true) +1, -1)

	-- Some ingots do not have unique sub-names.
	-- For these ingots, use their whole name, replacing ':' with '_'.
	-- Ex: talinite:ingot and brass:ingot have the same sub-name, "ingot".
	if ingot_name == "ingot" then
		ingot_name = string.gsub(ingot_item, ":", "_")
	end

	if is_big then
		ingot_name = ingot_name .. "_big"
		stack_size = 8
		texture_prefix = "ingot_big_"
	end

	--this way there is no need for a separate on_punch function for a stack of 1 ingot
	minetest.register_alias(mod_prefix .. ingot_name .."_0", "air")

	--gives the ingot_item the ability to be placed and increas already placed stacks of ingots
	minetest.override_item(ingot_item, {
		on_place = function (itemstack, placer, pointed_thing)
            local pos = minetest.get_pointed_thing_position(pointed_thing, true)
            if minetest.is_protected(pos, placer:get_player_name()) and not minetest.check_player_privs(placer, "protection_bypass") then
			    return
		    end
			if pointed_thing["type"] == "node" then
				local name = minetest.get_node(pointed_thing.under).name
				-- call on_rightclick function of pointed node if aplicable and not sneak
				-- might or might not break if item is placed by mod devices
				if minetest.registered_nodes[name].on_rightclick and
					not placer:get_player_control().sneak
				then
					minetest.registered_nodes[name].on_rightclick(pointed_thing.under,
						minetest.get_node(pointed_thing.under), placer, itemstack)
				elseif string.find(name, mod_prefix .. ingot_name) then
					local count = string.gsub(name, "%D*", "")
					if stack_size > minetest.registered_nodes[minetest.get_node(pointed_thing.under).name]._ingot_count then
						minetest.set_node(pointed_thing.under, {name = mod_prefix .. ingot_name .."_" .. count + 1, param2 = minetest.get_node(pointed_thing.under).param2})

						itemstack:take_item()
					elseif minetest.get_node(pointed_thing.above).name == "air" then
						minetest.set_node(pointed_thing.above, {name = mod_prefix .. ingot_name .."_1"})

						itemstack:take_item()
					end

				elseif minetest.get_node(pointed_thing.above).name == "air" then
					minetest.set_node(pointed_thing.above, {
						name = mod_prefix .. ingot_name .. "_1",
						param2 = math.random(0, 3),
					})

					itemstack:take_item()
				end

				return itemstack
			end
		end
	})

	-- Talinite ingots glow.
	local light_source = nil
	if ingot_item == "talinite:ingot" then
		light_source = 6
	end

	--registers 'stack_size' number of nodes, each has one more ingot in it than the last
	for i = 1, stack_size do
		local box = {
					type = "fixed",
					fixed = {
						--rectangular box which encompases all placed ingots
						ingots.get_box(is_big, i),
					},
				}
		minetest.register_node(mod_prefix .. ingot_name .. "_" .. i,{
			description = "ingots",
			drawtype = "mesh",
			tiles = {texture},
			mesh = texture_prefix .. i .. ".obj",
			selection_box = box,
			collision_box = box,
			paramtype = 'light',
			paramtype2 = "facedir",
			light_source = light_source,

			-- Not quick to walk on top of ingot piles.
			movement_speed_multiplier = default.SLOW_SPEED,

			-- Horizontal rotation only!
			on_rotate = screwdriver.rotate_simple,

			groups = {cracky = 3, level = 2, not_in_creative_inventory = 1, falling_node = 1},
			drop = ingot_item .. " " .. i,
			on_punch = function (pos, node, puncher, pointed_thing)
				if puncher then
					local wield = puncher:get_wielded_item()
					--checks, so that a stack can be taken appart only by hand or relevant ingot_item
					if wield:get_name() == ingot_item or
						wield:get_count() == 0 then
                        if minetest.is_protected(pos, puncher:get_player_name()) and not minetest.check_player_privs(puncher, "protection_bypass") then
			                return
		                end
						minetest.set_node(pos, {name = mod_prefix .. ingot_name .."_" .. i - 1, param2 = node.param2})

						local stack = ItemStack(ingot_item)
						puncher:get_inventory():add_item("main", stack)
					end
				end
			end,
			_ingot_name = ingot_name,
			_ingot_count = i,
		})
	end
end

--returns an apropriate nodebox for a given number of ingots
function ingots.get_box(is_big, i)
	if is_big then return {-0.5, -0.5, -0.5, 0.5, (((i + 1 - ((i +1 )%2)) / 8) - 0.5), 0.5}
	else return {-0.5, -0.5, -0.5, 0.5, (((i - 1 - ((i-1)%8)) / 8) - 3) / 8, 0.5}
	end
end