public Quaternion toRotationQuat() {
        Quaternion quat = new Quaternion();
        quat.fromRotationMatrix(toRotationMatrix());
        return quat;
    }
Determine the rotation component of this 3-D coordinate transform.

<p>Assumes (but does not verify) that the transform consists entirely of
translation, rotation, and positive scaling -- no reflection or shear.

@return a new rotation Quaternion
jme3-core/src/main/java/com/jme3/math/Matrix4f.java