LibGDX: How to draw in the area of the black bars of a FitViewport?

Question

I got a FitViewport with a virtual width and virtual height. When the screen got another aspect ratio than my virtual resolution black bars are added. I want to draw something inside these letterboxes.

I tried to do it that way, but only objects "inside" my virtual resolution are drawn, objects "outside" are just not visible:

viewport = new FitViewport(VIRTUAL_WIDTH, VIRTUAL_HEIGHT, cam);
viewport.apply();

batch.setProjectionMatrix(cam.combined);

batch.begin();
batch.draw(texture, viewport.getRightGutterX(), 0);
batch.end();

How to draw inside the letterboxes?

Answer 1

You would need a second viewport, probably ExtendViewport with the same virtual dimensions as your FitViewport.

//create:
fitViewport = new FitViewport(VIRTUAL_WIDTH, VIRTUAL_HEIGHT);
extendViewport = new ExtendViewport(VIRTUAL_WIDTH, VIRTUAL_HEIGHT);

//resize:
fitViewport.update(width, height);
extendViewport.update(width, height);

//render:

fitViewport.apply();
batch.setProjectionMatrix(fitViewport.getCamera().combined);
batch.begin();
//draw game
batch.end();

extendViewport.apply();
batch.setProjectionMatrix(extendViewport.getCamera().combined);
batch.begin();
//draw stuff in border
batch.end();

If you want to be sure the border stuff doesn't overlap your game, you could swap the draw order above.

Or you could just use ExtendViewport to begin with for everything.