Added gui_util

src/frontend/screens.cpp

@@ -81,11 +81,14 @@ void MenuScreen::draw(float delta) {
 	uishader->use();
 	uishader->uniformMatrix("u_projview", uicamera->getProjView());
 
+    uint width = Window::width;
+    uint height = Window::height;
+
     batch->begin();
     batch->texture(engine->getAssets()->getTexture("menubg"));
     batch->rect(0, 0, 
-                Window::width, Window::height, 0, 0, 0, 
-                UVRegion(0, 0, Window::width/64, Window::height/64), 
+                width, height, 0, 0, 0, 
+                UVRegion(0, 0, width/64, height/64), 
                 false, false, vec4(1.0f));
     batch->render();
 }