Check to see whether the geom has an offset. This function will return non-zero if the offset has been created. Note that there is a difference between a geom with no offset, and a geom with an offset that is the identity transform. In the latter case, although the observed behaviour is identical, there is a unnecessary computation involved because the geom will be applying the transform whenever it needs to recalculate its world position.
Non-zero if the geom has an offset, zero otherwise.