Manpages - SDL_VideoModeOK.3

SDL_VideoModeOK - Check to see if a particular video mode is supported.

#include “SDL.h”

int SDL_VideoModeOK*(*int width, int height, int bpp, Uint32 flags);

SDL_VideoModeOK returns 0 if the requested mode is not supported under any bit depth, or returns the bits-per-pixel of the closest available mode with the given width, height and requested surface flags (see SDL_SetVideoMode).

The bits-per-pixel value returned is only a suggested mode. You can usually request and bpp you want when setting the video mode and SDL will emulate that color depth with a shadow video surface.

The arguments to SDL_VideoModeOK are the same ones you would pass to SDL_SetVideoMode

  SDL_Surface *screen;
  Uint32 bpp;
  .
  .
  .
  printf("Checking mode 640x480@16bpp.
  ");
  bpp=SDL_VideoModeOK(640, 480, 16, SDL_HWSURFACE);

  if(!bpp){
    printf("Mode not available.
  ");
    exit(-1);
  }

  printf("SDL Recommends 640x480@%dbpp.
  ", bpp);
  screen=SDL_SetVideoMode(640, 480, bpp, SDL_HWSURFACE);
  .
  .

SDL_SetVideoMode, SDL_GetVideoInfo