In the paragraph "Physical interaction" a member variable called "mFloor" of type SceneGeometry* is created but not referenced. I think the following step should be: "mFloor = mScene->createSceneGeometry(new ..." instead of "mScene->createSceneGeometry(new ...". Correct me if I am wrong, I haven't changed it yet.

Yes, this variable isn't needed. If you later would need a pointer to the SceneGeometry, you could store it in it, but isn't needed here.

--> I removed it.