minetest/games/devtest/mods/testitems/init.lua

local S = core.get_translator("testitems")

--
-- Texture overlays for items
--

-- For the global overlay color test
local GLOBAL_COLOR_ARG = "orange"

-- Punch handler to set random color with "color" argument in item metadata
local overlay_on_use = function(itemstack, user, pointed_thing)
	local meta = itemstack:get_meta()
	local color = math.random(0x0, 0xFFFFFF)
	local colorstr = string.format("#%06x", color)
	meta:set_string("color", colorstr)
	core.log("action", "[testitems] Color of "..itemstack:get_name().." changed to "..colorstr)
	return itemstack
end
-- Place handler to clear item metadata color
local overlay_on_place = function(itemstack, user, pointed_thing)
	local meta = itemstack:get_meta()
	meta:set_string("color", "")
	return itemstack
end

core.register_craftitem("testitems:overlay_meta", {
	description = S("Texture Overlay Test Item, Meta Color") .. "\n" ..
		S("Image must be a square with rainbow cross (inventory and wield)") .. "\n" ..
		S("Item meta color must only change square color") .. "\n" ..
		S("Punch: Set random color") .. "\n" ..
		S("Place: Clear color"),
	-- Base texture: A grayscale square (can be colorized)
	inventory_image = "testitems_overlay_base.png",
	wield_image = "testitems_overlay_base.png",
	-- Overlay: A rainbow cross (NOT to be colorized!)
	inventory_overlay = "testitems_overlay_overlay.png",
	wield_overlay = "testitems_overlay_overlay.png",

	on_use = overlay_on_use,
	on_place = overlay_on_place,
	on_secondary_use = overlay_on_place,
})

core.register_craftitem("testitems:overlay_global", {
	description = S("Texture Overlay Test Item, Global Color") .. "\n" ..
		S("Image must be an orange square with rainbow cross (inventory and wield)"),
	-- Base texture: A grayscale square (to be colorized)
	inventory_image = "testitems_overlay_base.png",
	wield_image = "testitems_overlay_base.png",
	-- Overlay: A rainbow cross (NOT to be colorized!)
	inventory_overlay = "testitems_overlay_overlay.png",
	wield_overlay = "testitems_overlay_overlay.png",
	color = GLOBAL_COLOR_ARG,
})

core.register_craftitem("testitems:image_meta", {
	description = S("Image Override Meta Test Item"),
	inventory_image = "default_apple.png",
	wield_image = "basetools_icesword.png",

	on_use = function(itemstack, player)
		local meta = itemstack:get_meta()
		local state = meta:get_int("state")
		state = (state + 1) % 5
		meta:set_int("state", state)
		core.chat_send_player(player:get_player_name(), "State " .. state)

		if state == 0 then
			meta:set_string("inventory_image", "")
			meta:set_string("wield_image", "")
			meta:set_string("inventory_overlay", "")
			meta:set_string("wield_overlay", "")
			meta:set_string("wield_scale", "")
		elseif state == 1 then
			meta:set_string("inventory_image", "default_tree.png")
			meta:set_string("wield_image", "basetools_firesword.png")
		elseif state == 2 then
			meta:set_string("inventory_image", "default_apple.png^testitems_overridden.png")
			meta:set_string("wield_image", "basetools_icesword.png^testitems_overridden.png")
		elseif state == 3 then
			meta:set_string("inventory_image", "default_tree.png")
			meta:set_string("wield_image", "basetools_firesword.png")
			meta:set_string("inventory_overlay", "default_apple.png")
			meta:set_string("wield_overlay", "default_apple.png")
		elseif state == 4 then
			local scale = vector.new(0.5, 0.5, 0.5)
			meta:set_string("wield_scale", scale:to_string())
		end

		return itemstack
	end,
})

core.register_craftitem("testitems:telescope_stick", {
	description = S("Telescope Stick (Increases range on use.)"),
	inventory_image = "testitems_telescope_stick.png",
	on_use = function(itemstack, player)
		local meta = itemstack:get_meta()
		local range = meta:get_float("range") + 1.2
		if range > 10 then
			range = 0
		end
		meta:set_float("range", range)
		core.chat_send_player(player:get_player_name(), "Telescope Stick range set to "..range)
		return itemstack
	end,
})


-- Tree spawners

local tree_def={
    axiom="Af",
    rules_a="TT[&GB][&+GB][&++GB][&+++GB]A",
    rules_b="[+GB]fB",
    trunk="basenodes:tree",
    leaves="basenodes:leaves",
    angle=90,
    iterations=4,
    trunk_type="single",
    thin_branches=true,
}

core.register_craftitem("testitems:tree_spawner", {
	description = S("Tree Spawner"),
	inventory_image = "testitems_tree_spawner.png",
	on_place = function(itemstack, placer, pointed_thing)
		if (not pointed_thing or pointed_thing.type ~= "node") then
			return
		end
		core.spawn_tree(pointed_thing.above, tree_def)
	end,
})

local vmanip_for_trees = {} -- per player
core.register_craftitem("testitems:tree_spawner_vmanip", {
	description = S("Tree Spawner using VoxelManip"),
	inventory_image = "testitems_tree_spawner_vmanip.png",
	on_place = function(itemstack, placer, pointed_thing)
		if (not pointed_thing or pointed_thing.type ~= "node" or
				not core.is_player(placer)) then
			return
		end
		local name = placer:get_player_name()
		local vm = vmanip_for_trees[name]
		if not vm then
			vm = VoxelManip(vector.add(pointed_thing.above, 20),
				vector.subtract(pointed_thing.above, 20))
			vmanip_for_trees[name] = vm
			core.chat_send_player(name,
				"Tree in new VoxelManip spawned, left click to apply to map, "..
				"or right click to add more trees.")
		end
		core.spawn_tree_on_vmanip(vm, pointed_thing.above, tree_def)
	end,
	on_use = function(itemstack, user, pointed_thing)
		if not core.is_player(user) then
			return
		end
		local name = user:get_player_name()
		local vm = vmanip_for_trees[name]
		if vm then
			vm:write_to_map()
			vmanip_for_trees[name] = nil
			core.chat_send_player(name, "VoxelManip written to map.")
		end
	end,
})

core.register_on_leaveplayer(function(player, timed_out)
	vmanip_for_trees[player:get_player_name()] = nil
end)