VoxeLibre/mods/ITEMS/mcl_compass/init.lua

local S = minetest.get_translator(minetest.get_current_modname())

mcl_compass = {}

local compass_types = {
	{
		name = "compass",
		desc = S("Compass"),
		tt = S("Points to the world origin"),
		longdesc = S("Compasses are tools which point to the world origin (X=0, Z=0) or the spawn point in the Overworld."),
		usagehelp = S("A Compass always points to the world spawn point when the player is in the overworld.  In other dimensions, it spins randomly."),
	},
	{
		name = "compass_lodestone",
		desc = S("Lodestone Compass"),
		tt = S("Points to a lodestone"),
		longdesc = S("Lodestone compasses resemble regular compasses, but they point to a specific lodestone."),
		usagehelp = S("A Lodestone compass can be made from an ordinary compass by using it on a lodestone.  After becoming a lodestone compass, it always points to its linked lodestone, provided that they are in the same dimension.  If not in the same dimension, the lodestone compass spins randomly, similarly to a regular compass when outside the overworld.  A lodestone compass can be relinked with another lodestone."),
	}
}

-- Number of dynamic compass images (and items registered.)
local compass_frames = 32

-- The image/item that is craftable and shown in inventories.
local stereotype_frame = 18

-- random compass spinning tick in seconds.
-- Increase if there are performance problems.
local spin_timer_tick = 0.5

-- Local aliases to globals for better lua performance
local m_deg = math.deg
local m_atan2 = math.atan2
local m_floor = math.floor
local m_rnd = math.random
local vec_new = vector.new
local vec_from_str = vector.from_string
local get_connected_players = minetest.get_connected_players
local get_item_group = minetest.get_item_group
local setting_get_pos = minetest.setting_get_pos
local compass_works = mcl_worlds.compass_works
local y_to_layer = mcl_worlds.y_to_layer

-- Initialize random compass frame for spinning compass.  It is updated in
-- the compass globalstep function.
local random_frame = m_rnd(0, compass_frames-1)

local function get_far_node(pos, itemstack) --code from minetest dev wiki: https://dev.minetest.net/minetest.get_node, some edits have been made to add a cooldown for force loads
	local node = minetest.get_node(pos)
	if node.name == "ignore" then
		local tstamp = tonumber(itemstack:get_meta():get_string("last_forceload"))
		if tstamp == nil then --this is only relevant for new lodestone compasses, the ones that have never performes a forceload yet
			itemstack:get_meta():set_string("last_forceload", tostring(os.time(os.date("!*t"))))
			tstamp = tonumber(os.time(os.date("!*t")))
		end
		if tonumber(os.time(os.date("!*t"))) - tstamp > 180 then --current time in secounds - old time in secounds, if it is over 180 (3 mins): forceload
			itemstack:get_meta():set_string("last_forceload", tostring(os.time(os.date("!*t"))))
			minetest.get_voxel_manip():read_from_map(pos, pos)
			node = minetest.get_node(pos)
		else
			node = {name="mcl_compass:lodestone"} --cooldown not over yet, pretend like there is something...
		end
	end
	return node
end

--- Get compass needle angle.
-- Returns the angle that the compass needle should point at expressed in
-- 360 degrees divided by the number of possible compass image frames..
--
-- pos: position of the compass;
-- target: position that the needle points towards;
-- dir: rotational direction of the compass.
--
local function get_compass_angle(pos, target, dir)
	local angle_north = m_deg(m_atan2(target.x - pos.x, target.z - pos.z))
	if angle_north < 0 then angle_north = angle_north + 360 end
	local angle_dir = -m_deg(dir)
	local angle_relative = (angle_north - angle_dir + 180) % 360
	return m_floor((angle_relative/11.25) + 0.5) % compass_frames
end

--- Get compass image frame.
-- Returns the compass image frame with the needle direction matching the
-- compass' current position.
--
-- pos: position of the compass;
-- dir: rotational direction of the compass.
-- itemstack: the compass including its optional lodestone metadata.
--
local function get_compass_frame(pos, dir, itemstack)
	local lpos_str = itemstack:get_meta():get_string("pointsto")
	if lpos_str == "" then -- normal compass
		-- Compasses only work in the overworld
		if compass_works(pos) then
			local spawn_pos = setting_get_pos("static_spawnpoint")
				or vec_new(0, 0, 0)
			return get_compass_angle(pos, spawn_pos, dir)
		else
			return random_frame
		end
	else -- lodestone compass
		local lpos = vec_from_str(lpos_str)
		local _, l_dim = y_to_layer(lpos.y)
		local _, p_dim = y_to_layer(pos.y)
		-- compass and lodestone must be in the same dimension
		if l_dim == p_dim then
			--check if lodestone still exists
			if get_far_node(lpos, itemstack).name == "mcl_compass:lodestone" then
				return get_compass_angle(pos, lpos, dir)
			else -- lodestone got destroyed
				return random_frame
			end
		else
			return random_frame
		end
	end
end

--- Get partial compass itemname.
-- Returns partial itemname of a compass with needle direction matching compass position.
-- Legacy compatibility function for mods using older api.
--
function mcl_compass.get_compass_image(pos, dir, itemstack)
	minetest.log("warning", "mcl_compass: deprecated function " ..
		"get_compass_image() called, use get_compass_itemname().")
	local itemstack = ItemStack("mcl_compass:" .. stereotype_frame)
	local frame = get_compass_frame(pos, dir, itemstack)
	if itemstack:get_meta():get_string("pointsto") ~= "" then
		return frame .. "_lodestone"
	else
		return frame
	end
end

--- Get compass itemname.
-- Returns the itemname of a compass with needle direction matching the
-- current compass position.
--
-- pos: position of the compass;
-- dir: rotational orientation of the compass;
-- itemstack: the compass including its optional lodestone metadata.
--
function mcl_compass.get_compass_itemname(pos, dir, itemstack)
	if not itemstack then
		minetest.log("warning", "mcl_compass.get_compass_image called without itemstack!")
		return "mcl_compass:" .. stereotype_frame
	end
	local frame = get_compass_frame(pos, dir, itemstack)
	if itemstack:get_meta():get_string("pointsto") ~= "" then
		return "mcl_compass:" .. frame .. "_lodestone"
	else
		return "mcl_compass:" .. frame
	end
end

-- Timer for randomly spinning compass.
-- Gets updated and checked in the globalstep function.
local spin_timer = 0

-- Compass globalstep function.
-- * updates random spin counter and random frame of spinning compasses;
-- * updates all compasses in player's inventories to match the correct
--   needle orientations for their current positions.
--
minetest.register_globalstep(function(dtime)
	spin_timer = spin_timer + dtime
	if spin_timer >= spin_timer_tick then
		random_frame = (random_frame + m_rnd(-1, 1)) % compass_frames
		spin_timer = 0
	end

	local compass_nr, compass_frame
	local pos, dir, inv
	for _, player in pairs(get_connected_players()) do
		pos = player:get_pos()
		dir = player:get_look_horizontal()
		inv = player:get_inventory()
		for j, stack in pairs(inv:get_list("main")) do
			compass_nr = get_item_group(stack:get_name(), "compass")
			if compass_nr ~= 0 then
				-- check if current compass image still matches true orientation
				compass_frame = get_compass_frame(pos, dir, stack)
				if compass_nr - 1 ~= compass_frame then
					if stack:get_meta():get_string("pointsto") == "" then
						stack:set_name("mcl_compass:" .. compass_frame)
					else
						stack:set_name("mcl_compass:" .. compass_frame .. "_lodestone")
					end
					inv:set_stack("main", j, stack)
				end
			end
		end
	end
end)

--
-- Node and craftitem definitions
--
local doc_mod = minetest.get_modpath("doc")

for _, item in pairs(compass_types) do
	local name_fmt, img_fmt, stack_max
	if item.name == "compass" then
		name_fmt = "mcl_compass:%d"
		img_fmt = "mcl_compass_compass_%02d.png"
		stack_max = 64
	elseif item.name == "compass_lodestone" then
		name_fmt = "mcl_compass:%d_lodestone"
		img_fmt = "mcl_compass_compass_%02d.png^[colorize:purple:50"
		stack_max = 1
	end
	for i = 0, compass_frames - 1 do
		local def = {
			description = item.desc,
			_tt_help = item.tt,
			inventory_image = string.format(img_fmt, i),
			wield_image = string.format(img_fmt, i),
			stack_max = stack_max,
			groups = {compass = i + 1, tool = 1, disable_repair = 1},
		}
		if i == stereotype_frame then
			def._doc_items_longdesc = item.longdesc
			def._doc_items_usagehelp = item.usagehelp
		else
			def._doc_items_create_entry = false
			def.groups.not_in_creative_inventory = 1
		end
		local itemstring = string.format(name_fmt, i)
		minetest.register_craftitem(itemstring, table.copy(def))

		-- Help aliases. Makes sure the lookup tool works correctly
		if doc_mod and i ~= stereotype_frame then
			doc.add_entry_alias("craftitems", "mcl_compass:"..(stereotype_frame), "craftitems", itemstring)
		end
	end
end

minetest.register_craft({
	output = "mcl_compass:" .. stereotype_frame,
	recipe = {
		{"", "mcl_core:iron_ingot", ""},
		{"mcl_core:iron_ingot", "mesecons:redstone", "mcl_core:iron_ingot"},
		{"", "mcl_core:iron_ingot", ""}
	}
})

minetest.register_alias("mcl_compass:compass", "mcl_compass:" .. stereotype_frame)

-- Export stereotype item for other mods to use
mcl_compass.stereotype = "mcl_compass:" .. stereotype_frame


minetest.register_node("mcl_compass:lodestone",{
	description=S("Lodestone"),
	on_rightclick = function(pos, node, player, itemstack)
		if itemstack.get_name(itemstack).match(itemstack.get_name(itemstack),"mcl_compass:") then
			if itemstack.get_name(itemstack) ~= "mcl_compass:lodestone" then
				itemstack:get_meta():set_string("pointsto", minetest.pos_to_string(pos))
			end
		end
	end,
	tiles = {
		"lodestone_top.png",
		"lodestone_bottom.png",
		"lodestone_side1.png",
		"lodestone_side2.png",
		"lodestone_side3.png",
		"lodestone_side4.png"
	},
	groups = {pickaxey=1, material_stone=1},
	_mcl_hardness = 1.5,
	_mcl_blast_resistance = 6,
	sounds = mcl_sounds.node_sound_stone_defaults()
})

minetest.register_craft({
	output = "mcl_compass:lodestone",
	recipe = {
		{"mcl_core:stonebrickcarved","mcl_core:stonebrickcarved","mcl_core:stonebrickcarved"},
		{"mcl_core:stonebrickcarved", "mcl_core:diamondblock", "mcl_core:stonebrickcarved"},
		{"mcl_core:stonebrickcarved", "mcl_core:stonebrickcarved", "mcl_core:stonebrickcarved"}
	}
})