direction.set( pos ).subtractLocal( location ).normalizeLocal();
newDirection.set( pos ).subtractLocal( location ).normalizeLocal();
    public void lookAt( Vector3f pos, Vector3f worldUpVector ) {        direction.set( pos ).subtractLocal( location ).normalizeLocal();        // check to see if we haven't really updated camera -- no need to call        // sets.        if ( oldDirection.equals( direction ) ) {            return;        }        oldDirection.set( direction );        up.set( worldUpVector );        left.set( up ).crossLocal( direction ).normalizeLocal();        up.set( direction ).crossLocal( left ).normalizeLocal();        onFrameChange();    }