/**
* Get the value of this quaternion as an axis-angle value.
*
* @param aa The axis angle object to put the converted values into
*/
public void get(AxisAngle4d aa) {
double d = x * x + y * y + z * z;
if (d > EPSILON) {
d = Math.sqrt(d);
double inv_d = 1 / d;
aa.x = x * inv_d;
aa.y = y * inv_d;
aa.z = z * inv_d;
aa.angle = 2 * Math.atan2(d, angle);
} else {
aa.x = 0.0f;
aa.y = 1.0f;
aa.z = 0.0f;
aa.angle = 0.0f;
}
}
