camera.setUp(incr.mult(camera.getUp()));
    public void performAction(float time) {        incr.loadIdentity();        incr.fromAxisAngle(camera.getUp(), speed);        camera.setLeft(incr.mult(camera.getLeft()));        camera.setDirection(incr.mult(camera.getDirection()));        camera.setUp(incr.mult(camera.getUp()));        camera.update();    }