//------------------------------------------------------------------------
// Pixels: RGB array of size WH (rows) * WW (columns)
//------------------------------------------------------------------------

void SnapShot(unsigned byte* Pixels, unsigned WW, unsigned WH)
{ 
  
  FILE *fp;

  // GENERATE A UNIQUE FILENAME
  char FileName[40];
  static int SnapShotNum=100;
  int UniqueFound=0;  
  do { sprintf(FileName,"snap%d.ppm", SnapShotNum);
  if (fp=fopen(FileName,"r")) fclose(fp); else UniqueFound=1;
  SnapShotNum++;
  } while(!UniqueFound);

  unsigned NumPixels = WW * WH;
  if (Pixels==NULL) { printf("EMPTY PIXEL ARRAY!\n"); return; }

  fp = fopen(FileName, "wb");
  fprintf(fp, "P6\n%d %d\n255\n", WW, WH);
  fwrite(Pixels,1,NumPixels*3,fp);
  fclose(fp);
}