When a shader is missing, it'll use a default fallback (prevents loading game...

When a shader is missing, it'll use a default fallback (prevents loading game with missing DLCs/addons)

game/engines/default/data/gfx/shaders/fallback.frag

+uniform sampler2D tex;
+
+void main(void) {
+	gl_FragColor = texture2D(tex, gl_TexCoord[0].xy) * gl_Color;
+}

game/engines/default/data/gfx/shaders/fallback.lua

+-- TE4 - T-Engine 4
+-- Copyright (C) 2009 - 2018 Nicolas Casalini
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program.  If not, see <http://www.gnu.org/licenses/>.
+--
+-- Nicolas Casalini "DarkGod"
+-- darkgod@te4.org
+
+return {
+	frag = "fallback",
+	vert = nil,
+	args = {},
+	clone = false,
+	permanent = true,
+}

game/engines/default/engine/Shader.lua

@@ -177,7 +177,14 @@ function _M:loaded()
 	else
 		print("[SHADER] Loading from /data/gfx/shaders/"..self.name..".lua")
 		local f, err = loadfile("/data/gfx/shaders/"..self.name..".lua")
-		if not f and err then error(err) end
+		if not f and err then
+			if config.settings.cheat then
+				error(err)
+			else
+				print("[SHADER] "..self.name.." not found, using fallback")
+				f, err = loadfile("/data/gfx/shaders/fallback.lua")
+			end
+		end
 		setfenv(f, setmetatable(self.args or {}, {__index=_G}))
 		local def = f()