make ctx.frame_number overflow to 0

src/twn_loop.c

@@ -237,6 +237,9 @@ static void main_loop(void) {
 
             ctx.frame_accumulator -= ctx.desired_frametime;
             ctx.game.frame_number++;
+            /* TODO: should we ask for reinitialization in such case? */
+            if (ctx.game.frame_number > 16777216)
+                ctx.game.frame_number = 0;
             ctx.game.initialization_needed = false;
         }
     }