/**
* sfericka interpolace pomoci kvaternionu
*
* @param q kvaternion
* @param t vaha z intervalu <0;1>
* @return nova instance Poin3D
*/
public Quat slerp(Quat q, double t) {
double c = this.dot(q);
if (c > 1.0) c = 1.0;
else if (c < -1.0) c = -1.0;
double uhel = Math.acos(c);
if (Math.abs(uhel) < 1.0e-5) return new Quat(this);
double s = 1 / Math.sin(uhel);
if (t >= 1) return new Quat(this);
else if (t <= 0) return new Quat(q);
else
return new Quat(
this.renorm()
.mul(Math.sin((1 - t) * uhel) * s)
.add(q.renorm().mul(Math.sin(t * uhel) * s)))
.renorm();
}
