Trackable velocity

[samsartor]

Trackable objects need velocity data. Both linear and rotational. ViveController currently has a pose_delta, but that isn't very helpful for physics and momentum and stuff. There should be a way to get the tracked object's instantaneous velocity.

The length of the linear vector is speed (m/s).
The direction of the linear vector is direction of movement.
The length of the angular vector is speed (radians/s).
The direction of the angular vector is the axis of spin.

• Linear velocity (Vector3<f32>) on all Trackables
  • HmdMoment
  • ControllerMoment
  • MappedController
• Angular velocity (Vector3<f32>) on all Trackables
  • HmdMoment
  • ControllerMoment
  • MappedController

[samsartor]

Simple implementation from 7bdf668

Moment velocities might require #3