... qifengzheng): the thing no app seems to get right head tracking has no absolute forward. it infers a baseline from the imu and lets it drift. turning your head is the easy case. the one that breaks is slowly swiveling your whole body in a chair, which looks identical to a slow head turn. so the room either rotates with you, or re-centers and the hearth ends up behind you. the mac version had no head tracking ...