InternalInternalLoads a material color value into the viewer!Renderer.
SceneMesh calls this when we update SceneMesh.color.
InternalLoads the SceneMesh's modeling matrix into the viewer!Renderer.
SceneMesh calls this when we update SceneMesh.matrix.
Internal interface through which a SceneMesh loads attribute updates into a Viewer's Renderer.
This exists at each SceneMesh.rendererMesh when the containing SceneModel has been added to a Viewer.