PMG

int COpenGL_Win::change_video_mode ()
{

  DEVMODE dmScreenSettings;

  EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, &dm_old);

  yes_change_video_mode = 0;
  memset(&dmScreenSettings,0,sizeof(dmScreenSettings));
  dmScreenSettings.dmSize = sizeof(dmScreenSettings);
  dmScreenSettings.dmPelsWidth = os.width;
  dmScreenSettings.dmPelsHeight = os.height;
  dmScreenSettings.dmBitsPerPel = os.color_bits;
  dmScreenSettings.dmDisplayFrequency = os.frequency;
  dmScreenSettings.dmFields = DM_BITSPERPEL | DM_PELSWIDTH |
                              DM_PELSHEIGHT | DM_DISPLAYFREQUENCY;

  if (ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL)
    return return_error(IS_ERROR,"%s","change_video_mode -> ChangeDisplaySettings");
  Sleep(100);

  yes_change_video_mode = 1;

  return IS_OK;
 
}

/*  wglQueryDisplayModes
*
*  Query display modes
*
*/
static GLvoid wglQueryDisplayModes(DEVMODE **ppmode, GLint *pNumModes)
{
   GLint n = 0;
   DEVMODE  devmode;
   devmode.dmSize = sizeof(DEVMODE);

   while (EnumDisplaySettings(NULL, n, &devmode))
      n++;

   if (pNumModes)
      *pNumModes = n;

   /* fill an array with all the devmodes so we don't have to keep
      grabbing 'em. */
   if (ppmode)
   {
      DEVMODE * p = (DEVMODE*)malloc(sizeof(DEVMODE) * (n + 1));
      n = 0;
      p[n].dmSize = sizeof(DEVMODE);

      while (EnumDisplaySettings(NULL, n, p + n))
      {
         n++;
         p[n].dmSize = sizeof(DEVMODE);
      }
      *ppmode = p;
   }   
   return;
}

LONG SetDisplayMode(int x, int y, BYTE cbit,long freq){
DEVMODE DM;
//freq=NULL значит частоту неизменять
DM.dmSize = sizeof(DEVMODE);
DM.dmBitsPerPel = cbit; // глубина цвета, бит на пиксель
DM.dmPelsWidth = x; // разрешение по горизонтали
DM.dmPelsHeight = y; // разрешение по вертикали
if (freq!=NULL)
{DM.dmDisplayFrequency = freq; // частота обновления экрана
freq=DM_DISPLAYFREQUENCY;
}else freq=0;
DM.dmFields = DM_BITSPERPEL + DM_PELSWIDTH + DM_PELSHEIGHT + freq;

return ChangeDisplaySettings(&DM, 0);
};

glutGameModeString("800x600:32@100");
glutEnterGameMode();

int GetMaxFreq(int width, int height, int bits)
{
    DEVMODE dm;
    int i = 0;
    int max = 0;
    while(EnumDisplaySettings(0, i, &dm))
    {
        if(width == dm.dmPelsWidth && height == dm.dmPelsHeight && bits == dm.dmBitsPerPel)
            if(max < dm.dmDisplayFrequency) max = dm.dmDisplayFrequency;
        i++;
    }
    return max;
}