Quaternion q2 = new Quaternion();
q.lookAt(cam.getDirection(), cam.getUp());
Matrix3f v = new Matrix3f();
q.toRotationMatrix(v);
v.setColumn(1, new Vector3f(0,0,0));
v.setRow(1, new Vector3f(0,1,0));
q2.fromRotationMatrix(v);
rootNode.getChild("Player").setLocalRotation(q2);