bool SavePNM(const char *outputFile, const ui32 *pData, const i64 &width, const i64 &height)
{
  FILE *fp = fopen(outputFile, "wb");
  if (!fp) return false;
  fprintf(fp, "P6\n%d %d\n255\n", (i32)width, (i32)height);
  for (i64 y = 0; y < height; ++y) for (i64 x = 0; x < width; ++x) fwrite(pData + x + y * width, 1, 3, fp);
  fclose(fp);
  return true;
}