TrackTriggerTrait
constTrackTriggerTrait:Trait<{bottom:number;end:number;inside:boolean;lap:boolean;left:number;right:number;start:number;top:number; }>
A region of a track in its own coordinates, a box that reports a mover
riding through it: a rock’s hit box, a coin, a finish line. A mover has
no physics body, so the step tests its track coordinates rather than a
collider. A bound left out is open. The track is on TrackRefTrait, and
only a mover on that track is tested.