LibGDX Trying to get my head around box2d lights

I’ve written a simple libGDX screen to experiment with lighting and shadows and was delighted to discover how easy it all was. I think, however, there must be something I’m missing…

With 2 lights and 2 objects, the shadows are nearly, but not quite, what I’d expect. Here’s a screenshot:

Here’s the code used to create this:

public class LightsScreen extends RPGPlaygroundScreen {

    private RayHandler rayHandler;
    private World world;
    private Body squareBody;
    private Body circleBody;

    private Box2DDebugRenderer debugRenderer;

    public LightsScreen(Game game) {

    public void render(float delta) {
        debugRenderer.render(world, gameCamera.combined);

    public void show() {;
        world = new World(new Vector2(0, -9.8f), true);
        debugRenderer = new Box2DDebugRenderer();
        float distance = 12;
        int rays = 128;
        rayHandler = new RayHandler(world);
        rayHandler.setAmbientLight(0f, 0f, 0f, 0.5f);
        new PointLight(rayHandler, rays, Color.SKY, distance
                , (gameViewport.getWorldWidth() / 4)
                , (gameViewport.getWorldHeight() / 4) * 3 );
        new PointLight(rayHandler, rays, Color.PINK, distance
                , (gameViewport.getWorldWidth() / 4) * 3
                , (gameViewport.getWorldHeight() / 4) * 3);

    public void dispose() {

    private void createSquareBody() {
        //create definition
        BodyDef squareBodyDef = new BodyDef();
        squareBodyDef.type = BodyDef.BodyType.StaticBody;

        //set position
        squareBodyDef.position.set(gameViewport.getWorldWidth() / 3
                , gameViewport.getWorldHeight() / 3);

        //create body and add it to the world
        squareBody = world.createBody(squareBodyDef);

        //create shape
        PolygonShape squareBox = new PolygonShape();
        squareBox.setAsBox(1, 1);

        //create a fixture from the shape and add it to body
        squareBody.createFixture(squareBox, 2.0f);


    private void createShericalBody() {
        //create definition
        BodyDef circleBodyDef = new BodyDef();
        circleBodyDef.type = BodyDef.BodyType.StaticBody;

        //set position
        circleBodyDef.position.set((gameViewport.getWorldWidth() / 3) * 2
                , gameViewport.getWorldHeight() / 3);

        //create body and add it to the world
        circleBody = world.createBody(circleBodyDef);

        //create shape
        CircleShape shape = new CircleShape();

        //create a fixture from the shape and add it to body
        circleBody.createFixture(shape, 2.0f);

You can clearly see that the shadows don’t quite start where the object does. I’ve found that it improves if I add rays, but only up to about 128 - which is good, since I wouldn’t want to go higher than that anyway…

I’ve tried playing around with object density and restitution, without any effect. It’s possible that I’m simply misunderstanding how it’s supposed to work, or, perhaps, thinking in too few dimensions…

Do I just have unrealistic expectations? Is it actually working as intended? Am I simply being an idiot?

Does calling PointLight#setSoftnessLength(0) help ?

Indeed it does:

although I suppose you could argue it’s gone too far the other way now - gives me a starting point for experimentation though - thanks!

It’s not perfect.

If you want smoother lights without jitter, try:
If you want smoother lights without jitter and crashes, try: