@Override
public void initialize() {
physicsMapper = world.getMapper(Physics.class);
transformMapper = world.getMapper(Transform.class);
physicsWorld = new World(new Vector2f(0, 0), 10, new QuadSpaceStrategy(8, 6));
physicsWorld.enableRestingBodyDetection(1f, 1f, 1f);
physicsWorld.addListener(this);
}