Raycast Vehicle coordinate system confusion and wheel rotation issues

[aardvarkk]

I have filed a PR to fix this issue that goes into greater detail about the setup, but I wanted to file an issue as well in case other people run into this and want a place to look.

I believe the issue I was having is the same as the one documented here.

[stephengold]

There's definitely confusion around vehicle/wheel coordinate systems. Some of it may stem from how easy it is to unintentionally configure a left-handed coordinate system using btRaycastVehicle::setCoordinateSystem().

Instead of reversing signs yet again, I think a better way forward would be to define a (right,forward,up) basis for vehicle coordinates that's always right-handed. That would clarify correct usage of btRaycastVehicle while increasing its flexibility. I don't see any reason why a vehicle's forward direction must coincide with one of the local axes of its rigid body...