gauges/init.lua

-- gauges: Adds health/breath bars above players
--
-- Copyright © 2014-2020 4aiman, Hugo Locurcio and contributors - MIT License
-- See `LICENSE.md` included in the source distribution for details.

if minetest.settings:get_bool("health_bars") == false or
		not minetest.settings:get_bool("enable_damage")
then return end

-- Localize the vector distance function for better performance,
-- as it's called on every step
local vector_distance = vector.distance

local function add_gauge(player)
	if player and player:is_player() then
		local entity = minetest.add_entity(player:get_pos(), "gauges:hp_bar")
		local height = 19

		-- Check for Minetest 0.4.17 and adjust the entity height if needed
		-- (The entity height offset was changed in Minetest 5.0.0.)
		local version = tonumber(minetest.get_version().string:sub(1, 1))
		if version and version < 5 then
			height = 9
		end

		entity:set_attach(player, "", {x=0, y=height, z=0}, {x=0, y=0, z=0})
		entity:get_luaentity().wielder = player
	end
end

minetest.register_entity("gauges:hp_bar", {
	visual = "sprite",
	visual_size = {x=1, y=1/16, z=1},
	textures = {"blank.png"},
	collisionbox = {0},
	physical = false,

	on_step = function(self)
		local player = self.wielder
		local gauge = self.object

		if not player or not player:is_player() then
			gauge:remove()
			return
		elseif vector_distance(player:get_pos(), gauge:get_pos()) > 3 then
			gauge:remove()
			add_gauge(player)
			return
		end

		local hp = player:get_hp() <= 20 and player:get_hp() or 20
		local breath = player:get_breath() <= 10 and player:get_breath() or 11

		if self.hp ~= hp or self.breath ~= breath then
			gauge:set_properties({
				textures = {
					"health_"..hp..".png^"..
					"breath_"..breath..".png"
				}
			})
			self.hp = hp
			self.breath = breath
		end
	end
})

minetest.register_on_joinplayer(function(player)
	minetest.after(1, add_gauge, player)
end)

minetest.log("action", "[gauges] loaded.")