Make player burning HUD work without csm.

* Add update_hud() function.
* Remove the client channels.
* Unglobalize animation_frames variable.
* Fix bug where player state was not stored on shutdown of singleplayer
  game.
* Remove superfluous sanity_check() function, this code could easily be
  inlined in its only caller.

mods/ENTITIES/mcl_burning/api.lua

@@ -33,6 +33,29 @@ function mcl_burning.get_touching_nodes(obj, nodenames, storage)
 	return nodes
 end
 
+function mcl_burning.update_hud(player)
+	local animation_frames = tonumber(minetest.settings:get("fire_animation_frames")) or 8
+	local hud_flame_animated = "mcl_burning_hud_flame_animated.png^[opacity:180^[verticalframe:" .. animation_frames .. ":"
+
+	local storage = mcl_burning.get_storage(player)
+	if not storage.fire_hud_id then
+		storage.animation_frame = 1
+		storage.fire_hud_id = player:hud_add({
+			hud_elem_type = "image",
+			position = {x = 0.5, y = 0.5},
+			scale = {x = -100, y = -100},
+			text = hud_flame_animated .. storage.animation_frame,
+			z_index = 1000,
+		})
+	else
+		storage.animation_frame = storage.animation_frame + 1
+		if storage.animation_frame > animation_frames - 1 then
+			storage.animation_frame = 0
+		end
+		player:hud_change(storage.fire_hud_id, "text", hud_flame_animated .. storage.animation_frame)
+	end
+end
+
 function mcl_burning.set_on_fire(obj, burn_time)
 	if obj:get_hp() < 0 then
 		return
@@ -68,8 +91,7 @@ function mcl_burning.set_on_fire(obj, burn_time)
 
 	if not storage.burn_time or burn_time >= storage.burn_time then
 		if obj:is_player() then
-			mcl_burning.channels[obj]:send_all(tostring(mcl_burning.animation_frames))
-			mcl_burning.channels[obj]:send_all("start")
+			mcl_burning.update_hud(obj)
 		end
 		storage.burn_time = burn_time
 		storage.fire_damage_timer = 0
@@ -105,7 +127,9 @@ function mcl_burning.extinguish(obj)
 	if mcl_burning.is_burning(obj) then
 		local storage = mcl_burning.get_storage(obj)
 		if obj:is_player() then
-			mcl_burning.channels[obj]:send_all("stop")
+			if storage.fire_hud_id then
+				obj:hud_remove(storage.fire_hud_id)
+			end
 			mcl_burning.storage[obj] = {}
 		else
 			storage.burn_time = nil

mods/ENTITIES/mcl_burning/init.lua

@@ -1,14 +1,11 @@
 local modpath = minetest.get_modpath(minetest.get_current_modname())
 
 local pairs = pairs
-
 local get_connected_players = minetest.get_connected_players
 local get_item_group = minetest.get_item_group
 
 mcl_burning = {
-	storage = {},
-	channels = {},
-	animation_frames = tonumber(minetest.settings:get("fire_animation_frames")) or 8
+	storage = {}
 }
 
 dofile(modpath .. "/api.lua")
@@ -44,25 +41,33 @@ minetest.register_on_respawnplayer(function(player)
 	mcl_burning.extinguish(player)
 end)
 
-function mcl_burning.init_player(player)
-	local meta = player:get_meta()
-	-- NOTE: mcl_burning:data may be "return nil" (which deserialize into nil) for reasons unknown.
-	if meta:get_string("mcl_burning:data"):find("return nil", 1, true) then
-		minetest.log("warning", "[mcl_burning] 'mcl_burning:data' player meta field is invalid! Please report this bug")
+minetest.register_on_joinplayer(function(player)
+	local storage = {}
+	local burn_data = player:get_meta():get_string("mcl_burning:data")
+	if burn_data ~= "" then
+		storage = minetest.deserialize(burn_data)
 	end
-	mcl_burning.storage[player] = meta:contains("mcl_burning:data") and minetest.deserialize(meta:get_string("mcl_burning:data")) or {}
-	mcl_burning.channels[player] = minetest.mod_channel_join("mcl_burning:" .. player:get_player_name())
+	mcl_burning.storage[player] = storage
+end)
+
+local function on_leaveplayer(player)
+	local storage = mcl_burning.storage[player]
+	storage.fire_hud_id = nil
+	player:get_meta():set_string("mcl_burning:data", minetest.serialize(storage))
+	mcl_burning.storage[player] = nil
 end
 
-minetest.register_on_joinplayer(function(player)
-	mcl_burning.init_player(player)
-end)
-
 minetest.register_on_leaveplayer(function(player)
-	player:get_meta():set_string("mcl_burning:data", minetest.serialize(mcl_burning.storage[player]))
-	mcl_burning.storage[player] = nil
+	on_leaveplayer(player)
 end)
 
+minetest.register_on_shutdown(function()
+	for _,player in ipairs(minetest.get_connected_players()) do
+		on_leaveplayer(player)
+	end
+end)
+
+local animation_frames = tonumber(minetest.settings:get("fire_animation_frames")) or 8
 
 minetest.register_entity("mcl_burning:fire", {
 	initial_properties = {
@@ -73,7 +78,7 @@ minetest.register_entity("mcl_burning:fire", {
 			"mcl_burning_entity_flame_animated.png",
 			"mcl_burning_entity_flame_animated.png"
 		},
-		spritediv = {x = 1, y = mcl_burning.animation_frames},
+		spritediv = {x = 1, y = animation_frames},
 		pointable = false,
 		glow = -1,
 		backface_culling = false,
@@ -81,26 +86,25 @@ minetest.register_entity("mcl_burning:fire", {
 	animation_frame = 0,
 	animation_timer = 0,
 	on_activate = function(self)
-		self.object:set_sprite({x = 0, y = 0}, mcl_burning.animation_frames, 1.0 / mcl_burning.animation_frames)
+		self.object:set_sprite({x = 0, y = 0}, animation_frames, 1.0 / animation_frames)
 	end,
-	on_step = function(self)
-		if not self:sanity_check() then
-			self.object:remove()
-		end
-	end,
-	sanity_check = function(self)
+	on_step = function(self, dtime)
 		local parent = self.object:get_attach()
-
 		if not parent then
-			return false
+			self.object:remove()
+			return
 		end
-
 		local storage = mcl_burning.get_storage(parent)
-
 		if not storage or not storage.burn_time then
-			return false
+			self.object:remove()
+			return
+		end
+		if parent:is_player() then
+			self.animation_timer = self.animation_timer + dtime
+			if self.animation_timer >= 0.1 then
+				self.animation_timer = 0
+				mcl_burning.update_hud(parent)
+			end
 		end
-
-		return true
 	end,
 })