static void vrend_swizzle_data_bgra(uint64_t size, void *data) {
   const size_t bpp = 4;
   const size_t num_pixels = size / bpp;
   for (size_t i = 0; i < num_pixels; ++i) {
      unsigned char *pixel = ((unsigned char*)data) + i * bpp;
      unsigned char first  = *pixel;
      *pixel = *(pixel + 2);
      *(pixel + 2) = first;
   }
}
static void vrend_swizzle_data_bgra(uint64_t size, void *data) {
   const size_t bpp = 4;
   const size_t num_pixels = size / bpp;
   for (size_t i = 0; i < num_pixels; ++i) {
      unsigned char *pixel = ((unsigned char*)data) + i * bpp;
      unsigned char first  = *pixel;
      *pixel = *(pixel + 2);
      *(pixel + 2) = first;
   }
}