+ * Return the pixel value at (x, y)
+ * NOTE: The surface must be locked before calling this!
+ */
+Uint32 SuperTux::getpixel(SDL_Surface *surface, int x, int y)
+{
+ int bpp = surface->format->BytesPerPixel;
+ /* Here p is the address to the pixel we want to retrieve */
+ Uint8 *p = (Uint8 *)surface->pixels + y * surface->pitch + x * bpp;
+
+ switch(bpp) {
+ case 1:
+ return *p;
+
+ case 2:
+ return *(Uint16 *)p;
+
+ case 3:
+ if(SDL_BYTEORDER == SDL_BIG_ENDIAN)
+ return p[0] << 16 | p[1] << 8 | p[2];
+ else
+ return p[0] | p[1] << 8 | p[2] << 16;
+
+ case 4:
+ return *(Uint32 *)p;
+
+ default:
+ return 0; /* shouldn't happen, but avoids warnings */
+ }
+}
+
+/* 'Stolen' from the SDL documentation.