public static void GetShortestAngleAxisBetween(Quaternion a, Quaternion b, out Vector3 axis, out float angle)
{
var dq = Quaternion.Inverse(a) * b;
if (dq.w > 1)
{
dq = ExtQuaternion.Normalize(dq);
}
//get as doubles for precision
var qw = (double)dq.w;
var qx = (double)dq.x;
var qy = (double)dq.y;
var qz = (double)dq.z;
var ratio = System.Math.Sqrt(1.0d - qw * qw);
angle = (float)(2.0d * System.Math.Acos(qw)) * Mathf.Rad2Deg;
if (ratio < 0.001d)
{
axis = new Vector3(1f, 0f, 0f);
}
else
{
axis = new Vector3(
(float)(qx / ratio),
(float)(qy / ratio),
(float)(qz / ratio));
axis.Normalize();
}
}
public static void GetAngleAxis(this Quaternion q, out Vector3 axis, out float angle)
{
if (q.w > 1)
{
q = ExtQuaternion.Normalize(q);
}
//get as doubles for precision
var qw = (double)q.w;
var qx = (double)q.x;
var qy = (double)q.y;
var qz = (double)q.z;
var ratio = System.Math.Sqrt(1.0d - qw * qw);
angle = (float)(2.0d * System.Math.Acos(qw)) * Mathf.Rad2Deg;
if (ratio < 0.001d)
{
axis = new Vector3(1f, 0f, 0f);
}
else
{
axis = new Vector3(
(float)(qx / ratio),
(float)(qy / ratio),
(float)(qz / ratio));
axis.Normalize();
}
}