Function LoadEXRWithLayer

tutorials/common/image/tinyexr.h:6269–6515

}

int LoadEXRWithLayer(float **out_rgba, int *width, int *height,
                     const char *filename, const char *layername,
                     const char **err) {
  if (out_rgba == NULL) {
    tinyexr::SetErrorMessage("Invalid argument for LoadEXR()", err);
    return TINYEXR_ERROR_INVALID_ARGUMENT;
  }

  EXRVersion exr_version;
  EXRImage exr_image;
  EXRHeader exr_header;
  InitEXRHeader(&exr_header);
  InitEXRImage(&exr_image);

  {
    int ret = ParseEXRVersionFromFile(&exr_version, filename);
    if (ret != TINYEXR_SUCCESS) {
      std::stringstream ss;
      ss << "Failed to open EXR file or read version info from EXR file. code("
         << ret << ")";
      tinyexr::SetErrorMessage(ss.str(), err);
      return ret;
    }

    if (exr_version.multipart || exr_version.non_image) {
      tinyexr::SetErrorMessage(
          "Loading multipart or DeepImage is not supported  in LoadEXR() API",
          err);
      return TINYEXR_ERROR_INVALID_DATA;  // @fixme.
    }
  }

  {
    int ret = ParseEXRHeaderFromFile(&exr_header, &exr_version, filename, err);
    if (ret != TINYEXR_SUCCESS) {
      FreeEXRHeader(&exr_header);
      return ret;
    }
  }

  // Read HALF channel as FLOAT.
  for (int i = 0; i < exr_header.num_channels; i++) {
    if (exr_header.pixel_types[i] == TINYEXR_PIXELTYPE_HALF) {
      exr_header.requested_pixel_types[i] = TINYEXR_PIXELTYPE_FLOAT;
    }
  }

  // TODO: Probably limit loading to layers (channels) selected by layer index
  {
    int ret = LoadEXRImageFromFile(&exr_image, &exr_header, filename, err);
    if (ret != TINYEXR_SUCCESS) {
      FreeEXRHeader(&exr_header);
      return ret;
    }
  }

  // RGBA
  int idxR = -1;