Hack to let TP authors override inv/wield images

mods/nc_api/init.lua

@@ -76,3 +76,4 @@ include("item_nodebox_zfighting")
 include("item_virtual")
 include("item_stackmax")
 include("item_touch_hurt")
+include("item_txp_overlay")

mods/nc_api/item_txp_overlay.lua

@@ -0,0 +1,41 @@
+-- LUALOCALS < ---------------------------------------------------------
+local io, minetest, nodecore, pairs, table, type
+    = io, minetest, nodecore, pairs, table, type
+local io_open, table_concat, table_sort
+    = io.open, table.concat, table.sort
+-- LUALOCALS > ---------------------------------------------------------
+
+local missing = {}
+
+minetest.after(0, function()
+		local t = {}
+		for k in pairs(missing) do t[#t + 1] = k end
+		if #t < 1 then return end
+		table_sort(t)
+		minetest.log("WARNING: missing txp override images:\n\t"
+			.. table_concat(t, "\n\t"))
+	end)
+
+local function overlay(name, img, imgtype)
+	if (not img) or (img == "") or (type(img) ~= "string")
+	or (not img:match("%^")) or img:match("%^txp_") then return img end
+
+	local tpath = "txp_" .. name:gsub("^%W+", "")
+	:gsub("%W+", "_") .. "_" .. imgtype .. ".png"
+
+	local fullpath = minetest.get_modpath(minetest.get_current_modname())
+	.. "/textures/" .. tpath
+	local f = io_open(fullpath, "rb")
+	if not f then
+		missing[fullpath] = img
+		return img
+	end
+	f:close()
+
+	return img .. "^" .. tpath .. "^[makealpha:255,254,2"
+end
+
+nodecore.register_on_register_item(function(name, def)
+		def.inventory_image = overlay(name, def.inventory_image, "inv")
+		def.wield_image = overlay(name, def.wield_image, "wield")
+	end)