I've started changing the 3D engine I use for Passenger from JOGL to JMonkeyEngine. Unfortunately, I seem to be having trouble with my perspective:-
It seems to be drawing the closest objects first (and even the closest parts of the cloest objects first), which are getting over-drawn by objects that are further away. Still, it all moves at a good speed, and as soon I sort this out it should make the game a lot better. Maybe I could use this new feature for a psychadelic 3D puzzle game?