diff --git a/demo1.cpp b/demo1.cpp
index a1ee53b..0dea3e0 100644
--- a/demo1.cpp
+++ b/demo1.cpp
@@ -10,6 +10,9 @@
   license: CC0 1.0
 */
 
+//#define COMPUTE_WALL_TEXCOORDS 0
+  // ^ this turns off textures
+
 // redefine some parameters
 #define FPS 60
 #define GRAVITY_ACCELERATION (UNITS_PER_SQUARE * 3)
@@ -1007,7 +1010,12 @@ inline void pixelFunc(PixelInfo *pixel)
     if (intensity < 0)
       intensity = 0;
 
+#if COMPUTE_WALL_TEXCOORDS == 1
     c = sampleImage(textures[pixel->hit.type],pixel->texCoords.x,pixel->texCoords.y);
+#else
+    c = textures[pixel->hit.type][2];
+#endif
+
     c = addIntensity(c,intensity - 3);
   }
   else
diff --git a/demo2.cpp b/demo2.cpp
index ffef11f..23ed886 100644
--- a/demo2.cpp
+++ b/demo2.cpp
@@ -28,6 +28,9 @@
 //#define NO_TEXTURES
   /* ^ Turns off textures and only uses colors, which increases FPS. */
 
+//#define NO_SHADING
+  /* ^ Turns off shading (fog) which increases FPS. */
+
 //#define USE_DIST_APPROX 1 
   /* ^ Turns on distance approximation, which won't compute exact distances but
        only approximations - this should increase performance a little, but
@@ -948,6 +951,7 @@ inline void pixelFunc(PixelInfo *pixel)
       textureAverageColors[pixel->hit.type];
 #endif
 
+#ifndef NO_SHADING
     if (previousColumn == pixel->position.x)
     {
       c = addIntensity(c,pixelIntensity);
@@ -959,6 +963,8 @@ inline void pixelFunc(PixelInfo *pixel)
       previousColumn = pixel->position.x;
       c = addIntensity(c,pixelIntensity);
     }
+#endif
+
   }
 
   putSubsampledPixel // macro