diff --git a/demo1.cpp b/demo1.cpp
index e62cc81..a1ee53b 100644
--- a/demo1.cpp
+++ b/demo1.cpp
@@ -11,7 +11,7 @@
 */
 
 // redefine some parameters
-#define FPS 40
+#define FPS 60
 #define GRAVITY_ACCELERATION (UNITS_PER_SQUARE * 3)
 #define PLAYER_JUMP_SPEED 700
 #define CAMERA_COLL_HEIGHT_BELOW ((3 * UNITS_PER_SQUARE) / 2)
@@ -950,10 +950,13 @@ const unsigned char spriteTorch2[] =
 const unsigned char *textures[] = {texture1, texture2, texture3, texture4};
 
 #define withinMapReturn(what,whatElse)\
-  int16_t index = (LEVEL_Y_RES - y - 1) * LEVEL_X_RES + x;\
-  if (index > 0 && index < LEVEL_Y_RES * LEVEL_X_RES)\
+  if (x >= 0 && x < LEVEL_X_RES && y >= 0 && y < LEVEL_Y_RES)\
+  {\
+    int16_t index = (LEVEL_Y_RES - y - 1) * LEVEL_X_RES + x;\
     return (what);\
-  return (whatElse);
+  }\
+  else\
+    return (whatElse);
 
 Unit textureAt(int16_t x, int16_t y)
 {