pub fn nlerp(q1: Rot, q2: Rot, t: f32) -> Rot
Normalized linear interpolation https://fgiesen.wordpress.com/2012/08/15/linear-interpolation-past-present-and-future/ https://web.archive.org/web/20170825184056/http://number-none.com/product/Understanding%20Slerp,%20Then%20Not%20Using%20It/