function horizonOrientation
navball.ts:63
The horizon as an orientation: the rotation taking horizon axes into the axes the frame is expressed in.
north is squared against up before it is used, because a horizon
built from a body's pole is only perpendicular to within the rounding of
the projection that made it, and a basis a millionth off orthonormal is a
quaternion fromBasis normalizes into a slightly different rotation.
- horizonHorizonFrame
- Undocumented
ReturnsQuat