The sub-sectors are now working. Sub-sectors are extra walls, floor and ceiling within a sector/room. You can jump, and the collision handling works alright - not perfect.
Edit Dear lord, there's a bug! I forgot to add a limit for the angle when looking up/down, so you can actually spin around 180 degrees (flip upside down) and become very confused. Sorry.
Edit Dear lord, there's a bug! I forgot to add a limit for the angle when looking up/down, so you can actually spin around 180 degrees (flip upside down) and become very confused. Sorry.