Fix heart + bubble bar size on different texture packs

Add DPI support for statbar
Move heart+bubble bar to Lua HUD
Add statbar size (based upon an idea by blue42u)
Add support for customizing breath and statbar

builtin/builtin.lua

@@ -29,3 +29,4 @@ dofile(modpath.."/features.lua")
 dofile(modpath.."/voxelarea.lua")
 dofile(modpath.."/vector.lua")
 dofile(modpath.."/forceloading.lua")
+dofile(modpath.."/statbars.lua")

builtin/misc_register.lua

@@ -389,6 +389,7 @@ end
 
 minetest.registered_on_chat_messages, minetest.register_on_chat_message = make_registration()
 minetest.registered_globalsteps, minetest.register_globalstep = make_registration()
+minetest.registered_playerevents, minetest.register_playerevent = make_registration()
 minetest.registered_on_mapgen_inits, minetest.register_on_mapgen_init = make_registration()
 minetest.registered_on_shutdown, minetest.register_on_shutdown = make_registration()
 minetest.registered_on_punchnodes, minetest.register_on_punchnode = make_registration()

builtin/statbars.lua

@@ -0,0 +1,160 @@
+
+local health_bar_definition =
+{
+	hud_elem_type = "statbar",
+	position = { x=0.5, y=1 },
+	text = "heart.png",
+	number = 20,
+	direction = 0,
+	size = { x=24, y=24 },
+	offset = { x=(-10*24)-25, y=-(48+24+10)},
+}
+
+local breath_bar_definition =
+{
+	hud_elem_type = "statbar",
+	position = { x=0.5, y=1 },
+	text = "bubble.png",
+	number = 20,
+	direction = 0,
+	size = { x=24, y=24 },
+	offset = {x=25,y=-(48+24+10)},
+}
+
+local hud_ids = {}
+
+local function initialize_builtin_statbars(player)
+
+	if not player:is_player() then
+		return
+	end
+
+	local name = player:get_player_name()
+
+	if name == "" then
+		return
+	end
+
+	if (hud_ids[name] == nil) then
+		hud_ids[name] = {}
+	end
+
+	if player:hud_get_flags().healthbar then
+		if hud_ids[name].id_healthbar == nil then
+			health_bar_definition.number = player:get_hp()
+			hud_ids[name].id_healthbar  = player:hud_add(health_bar_definition)
+		end
+	else
+		if hud_ids[name].id_healthbar ~= nil then
+			player:hud_remove(hud_ids[name].id_healthbar)
+			hud_ids[name].id_healthbar = nil
+		end
+	end
+
+	if (player:get_breath() < 11) then
+		if player:hud_get_flags().breathbar then
+			if hud_ids[name].id_breathbar == nil then
+				hud_ids[name].id_breathbar = player:hud_add(breath_bar_definition)
+			end
+		else
+			if hud_ids[name].id_breathbar ~= nil then
+				player:hud_remove(hud_ids[name].id_breathbar)
+				hud_ids[name].id_breathbar = nil
+			end
+		end
+	elseif hud_ids[name].id_breathbar ~= nil then
+		player:hud_remove(hud_ids[name].id_breathbar)
+		hud_ids[name].id_breathbar = nil
+	end
+end
+
+local function cleanup_builtin_statbars(player)
+
+	if not player:is_player() then
+		return
+	end
+
+	local name = player:get_player_name()
+
+	if name == "" then
+		return
+	end
+
+	hud_ids[name] = nil
+end
+
+local function player_event_handler(player,eventname)
+	assert(player:is_player())
+
+	local name = player:get_player_name()
+
+	if name == "" then
+		return
+	end
+
+	if eventname == "health_changed" then
+		initialize_builtin_statbars(player)
+
+		if hud_ids[name].id_healthbar ~= nil then
+			player:hud_change(hud_ids[name].id_healthbar,"number",player:get_hp())
+			return true
+		end
+	end
+
+	if eventname == "breath_changed" then
+		initialize_builtin_statbars(player)
+
+		if hud_ids[name].id_breathbar ~= nil then
+			player:hud_change(hud_ids[name].id_breathbar,"number",player:get_breath()*2)
+			return true
+		end
+	end
+
+	if eventname == "hud_changed" then
+		initialize_builtin_statbars(player)
+		return true
+	end
+
+	return false
+end
+
+function minetest.hud_replace_builtin(name, definition)
+
+	if definition == nil or
+		type(definition) ~= "table" or
+		definition.hud_elem_type ~= "statbar" then
+		return false
+	end
+
+	if name == "health" then
+		health_bar_definition = definition
+
+		for name,ids in pairs(hud_ids) do
+			local player = minetest.get_player_by_name(name)
+			if  player and hud_ids[name].id_healthbar then
+				player:hud_remove(hud_ids[name].id_healthbar)
+				initialize_builtin_statbars(player)
+			end
+		end
+		return true
+	end
+
+	if name == "breath" then
+		breath_bar_definition = definition
+
+		for name,ids in pairs(hud_ids) do
+			local player = minetest.get_player_by_name(name)
+			if  player and hud_ids[name].id_breathbar then
+				player:hud_remove(hud_ids[name].id_breathbar)
+				initialize_builtin_statbars(player)
+			end
+		end
+		return true
+	end
+
+	return false
+end
+
+minetest.register_on_joinplayer(initialize_builtin_statbars)
+minetest.register_on_leaveplayer(cleanup_builtin_statbars)
+minetest.register_playerevent(player_event_handler)