Converting surface from 32 bpp to 24 bpp

SDL Development
1

Hi, (sorry for my english)
I need to convert one surface (32bpp) to another (24bpp), so the new surface has
only RGB components. I think that the function for this job is
SDL_ConvertSurface(SDL_Surface *src, SDL_PixelFormat *fmt, Uint32 flags) but it
seems I’m doing something wrong. I’m not sure what values should I set to the
new format.
Thanks for any help.

Bedrich Michalek

2

Bedrich Michalek wrote:

Hi, (sorry for my english)
I need to convert one surface (32bpp) to another (24bpp), so the new surface has
only RGB components. I think that the function for this job is
SDL_ConvertSurface(SDL_Surface *src, SDL_PixelFormat *fmt, Uint32 flags) but it
seems I’m doing something wrong. I’m not sure what values should I set to the
new format.
Thanks for any help.

Two solutions :

  • you can fill the SDL_PixelFormat structure directly (see the man page
    for SDL_PixelFormat) but this pixel format has to match the destination
    surface format.
  • you create a new surface of the right format with SDL_CreateRGBSurface
    and then do a blit to it :

destination = SDL_CreateRGBSurface(flags, width, height, 24, 0x000000ff,
0x0000ff00, 0x00ff0000, 0x00000000);
SDL_BlitSurface(source, NULL, destination, NULL);

Stephane