Raycast vehicle chassis position bug

[ragerma]

I encountered a problem that when getting the position of the chassis, it always seems lag behind the wheels especially when the vehicle moves fast. I fixed this problem by getting the position through the motionState object.

m_vehicle->getChassisWorldTransform().getOpenGLMatrix(&m); //this gives the wrong position of the chassis.
m_carChassis->getWorldTransform().getOpenGLMatrix(&m);//this also gives the wrong position of the chassis.

btTransform tr;
m_carChassis->getMotionState()->getWorldTransform(tr);//this gives the right position.
tr.getOpenGLMatrix(&m);

[Erwin Coumans]

Actually this is not a bug, but it should be better documented indeed.

Users should use the motion state for properly interpolated transforms. This becomes more apparent for high speed objects with interpolation. There is some mention about this in the Bullet manual, but obviously not enough.

Thanks,
Erwin