+ // force using RGBA surface for temporary bitmap (using transparent black)
+ SDL_SetColorKey(tmp_bitmap->surface, SET_TRANSPARENT_PIXEL,
+ SDL_MapRGB(tmp_bitmap->surface->format, 0x00, 0x00, 0x00));
+
+ tmp_bitmap->surface =
+ SDL_ConvertSurfaceFormat(tmp_bitmap->surface, SDL_PIXELFORMAT_RGBA32, 0);
+