This PR fixes a crash caused by the improperly ensured lifetime of RigGeometry::mSourceGeometry. mSourceGeometry was not adequate to ensure mSourceGeometry would outlive mGeometry because we extend mGeometrys lifetime beyond this lifetime by passing mGeometry to the draw traversal instead of this.
In addition,
We add important comments.
We detect and prevent generally unsafe operations in high level code.
We add a sprinkling of const to help clarify intentions.