LibGDX Background Image in FitViewport

Question

So, I'm using LibGDX for my upcoming App.

I use a FitViewport to ensure the 16:9 aspect ratio. So players with other aspect ratios than 16:9 will have black bars at sites.

What is the best way, to draw a screen filling background image, that also covers the area, where the black bars would be?

    camera = new OrthographicCamera();
    viewport = new FitViewport(WIDTH, HEIGHT, camera);
    viewport.apply();
    camera.position.set(WIDTH / 2, HEIGHT / 2, 0);
    camera.update();

Thats how I set up my camera/viewport currently.

I then draw stuff on it with a SpriteBatch.

Gdx.gl.glClearColor(1, 1, 1, 1);

That's how I currently at least change the color of the black bars, to any RGB color.

Answer 1

In my opinion, the best idea is to create a second stage and it's own Viewport only for background purposes. This second Viewport should not be FillViewport - it will strech your graphics from my experience. I think ExtendViewport is better in this case.

So how should it look:

    Stage stage, backStage;
    FitViewport viewport;
    ExtendViewport backViewport;

    ...

    stage = new Stage(); //this is your normal stage you have now
    stage.setViewport( yourFitViewport ); //here you are assingning fit viewport

    backViewport = new ExtendViewport( screenWidth, screenHeight );

    backStage = new Stage();
    backStage.setViewport( backViewport ); 

    ...
    //now add to backStage your background Image

    backStage.addActor( yourBackground );

Now just handle new stage in the render method.

    backStage.act();
    stage.act();

    backStage.draw(); //backStage first - we want it under stage
    stage.draw();

And update new Viewport in update or render like your old one. That's all.

Read more about Viewports here: https://github.com/libgdx/libgdx/wiki/Viewports