angle between the phone's gravity sensor and MegaSaM's "up", per frame

phone (camera frustum), this frame
MegaSaM camera path so far
phone gravity sensor, carried into the world by MegaSaM
true up (world z)
points: MegaSaM depth of this frame, metres (phone stereo scale)

drag = orbit, right-drag = pan, wheel = zoom, ←/→ = frame, space = play