Quaternion SpringRotation(Quaternion current, Quaternion target)
{
var v_current = current.ToVector4();
var v_target = target.ToVector4();
_vrotation = ETween.Step(_vrotation, Vector4.zero, 1 + _rotationSpeed * 0.5f);
_vrotation += (v_target - v_current) * (_rotationSpeed * 0.1f);
return (v_current + _vrotation * Time.deltaTime).ToNormalizedQuaternion();
}
public static Quaternion Step(
Quaternion current, Quaternion target,
ref Vector4 velocity, float omega)
{
var vcurrent = current.ToVector4();
var vtarget = target.ToVector4();
// We can use either of vtarget/-vtarget. Use closer one.
if (Vector4.Dot(vcurrent, vtarget) < 0) vtarget = -vtarget;
var dt = Time.deltaTime;
var n1 = velocity - (vcurrent - vtarget) * (omega * omega * dt);
var n2 = 1 + omega * dt;
velocity = n1 / (n2 * n2);
return (vcurrent + velocity * dt).ToNormalizedQuaternion();
}
