Attempt to create "fancy" hotbar.

Seems this doesn't actually work.  The hotbar image
MUST be a physical file, and cannot use any texture
modifiers, so sayeth the engine.

mods/nc_lux/radiation.lua

@@ -12,8 +12,8 @@ local irradiated = modname .. ":irradiated"
 minetest.register_craftitem(irradiated, {
 		description = "Burn",
 		stack_max = 1,
-		inventory_image = modname .. "_base.png^[mask:"
-		.. modname .. "_icon_mask.png",
+		inventory_image = "[combine:1x1",
+		hotbar_type = "burn",
 		wield_image = hand.wield_image,
 		wield_scale = hand.wield_scale,
 		on_drop = function(stack) return stack end,

mods/nc_player_health/injury.lua

@@ -10,7 +10,8 @@ local injured = modname .. ":injured"
 minetest.register_craftitem(injured, {
 		description = "Injury",
 		stack_max = 1,
-		inventory_image = modname .. "_injured.png",
+		inventory_image = "[combine:1x1",
+		hotbar_type = "injury",
 		wield_image = hand.wield_image,
 		wield_scale = hand.wield_scale,
 		on_drop = function(stack) return stack end,

mods/nc_player_hud/setup.lua

@@ -1,10 +1,12 @@
 -- LUALOCALS < ---------------------------------------------------------
-local math, minetest, nodecore, pairs
-    = math, minetest, nodecore, pairs
+local math, minetest, nodecore
+    = math, minetest, nodecore
 local math_floor
     = math.floor
 -- LUALOCALS > ---------------------------------------------------------
 
+local hotbar_slots = 8
+
 local function breathimg(br)
 	local o = 255 * (1 - br / 11)
 	if o == 0 then return "" end
@@ -34,11 +36,51 @@ end
 minetest.register_on_priv_grant(grantrevoke)
 minetest.register_on_priv_revoke(grantrevoke)
 
+local hotbars = {}
+
+local bar_scale = 32
+local function sethotbar(player)
+	local bar = "[combine:" .. (hotbar_slots * bar_scale) .. "x" .. bar_scale
+	local sel = "nc_player_hud_sel"
+	local inv = player:get_inventory()
+	for i = 1, hotbar_slots do
+		local img = "nc_player_hud_bar"
+		local stack = inv:get_stack("main", i)
+		local def = stack and (not stack:is_empty()) and stack:get_definition()
+		if def and def.hotbar_type then
+			img = img .. "_" .. def.hotbar_type
+			if i == player:get_wield_index() then
+				sel = sel .. "_" .. def.hotbar_type
+			end
+		end
+		bar = bar .. ":" .. (i * bar_scale - bar_scale) .. ",0=" .. img
+		.. ".png"--\\^[resize\\:" .. bar_scale .. "x" .. bar_scale
+	end
+	sel = sel .. ".png^[resize:" .. bar_scale .. "x" .. bar_scale
+
+	local pname = player:get_player_name()
+	local old = hotbars[pname]
+	if not old then
+		old = {}
+		hotbars[pname] = old
+	end
+	if old.bar ~= bar then
+		player:hud_set_hotbar_image(bar)
+		old.bar = bar
+	end
+	if old.sel ~= sel then
+		player:hud_set_hotbar_selected_image(sel)
+		old.sel = sel
+	end
+end
+
+minetest.register_on_leaveplayer(function(player)
+		hotbars[player:get_player_name()] = nil
+	end)
+
 minetest.register_on_joinplayer(function(player)
 		sethudflags(player)
-		player:hud_set_hotbar_itemcount(8)
-		player:hud_set_hotbar_image("nc_player_hud_bar.png")
-		player:hud_set_hotbar_selected_image("nc_player_hud_sel.png")
+		sethotbar(player)
 
 		if not minetest.settings:get_bool("enable_damage") then
 			player:set_breath(11)
@@ -61,5 +103,6 @@ minetest.register_globalstep(function()
 					label = "breath",
 					text = breathimg(player:get_breath())
 				})
+			sethotbar(player)
 		end
 	end)