The Z-axis angle a pure Z-rotation quaternion represents: 2 ยท atan2(z, w).
Exported on its own because it is the half of the mapping worth testing
directly, and because a caller that already knows its quaternion is planar
should not pay for the check again.
The Z-axis angle a pure Z-rotation quaternion represents:
2 ยท atan2(z, w).Exported on its own because it is the half of the mapping worth testing directly, and because a caller that already knows its quaternion is planar should not pay for the check again.