function* makeFaceNamesIterator() {
  yield CubeMap.FaceName.POSITIVEX;
  yield CubeMap.FaceName.NEGATIVEX;
  yield CubeMap.FaceName.POSITIVEY;
  yield CubeMap.FaceName.NEGATIVEY;
  yield CubeMap.FaceName.POSITIVEZ;
  yield CubeMap.FaceName.NEGATIVEZ;
}
An enum defining the names of the faces of a cube map.
@alias {CubeMap.FaceName}
@enum {string}
@private