Libgdx circle with linewidth

Question

I've started using libgdx and am trying to simply make a circle with a pretty thick stroke. As of yet I have not found anyway to make a stroke at all. pixmap.setStrokeWidth() is even in the API but appears to have been removed (?), and Gdx.gl10.glLineWidth(width); has no effect. How can I just change the stroke of the line? Here is a snippet of my current code:

@Override
public void create() {
    w = Gdx.graphics.getWidth();
    batch = new SpriteBatch();
    pixmap = new Pixmap(2 * w, 2 * w, Pixmap.Format.RGBA8888);
    pixmap.setColor(Color.BLACK);

    pixmap.drawCircle(w, w, w);
    texture = new Texture(pixmap);
    pixmap.dispose();

    sprite = new Sprite(texture);
}

@Override
public void render() {
    Gdx.gl.glClearColor(1, 1, 1, 1);
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

    batch.begin();
    sprite.setPosition(-w / 2, -w);
    sprite.draw(batch);
    batch.end();
}

Random shot: What's the default color of a Pixmap? Could it be the code's drawing black on black onto the Pixmap? — Stefan Hanke, Aug 28 '14 at 07:58

score 6 · Accepted Answer · edited May 23 '17 at 11:33

The OpenGL "line width" API is lame. The standard only requires that width 1.0 is supported, so many implementations (especially in mobile devices) do not support more than that. See Libgdx gl10.glLineWidth().

You might try drawing two filled discs, both with the same center. The second one should have a smaller radius and should be drawn to the Pixmap in such a way to set the alpha to 0 where its drawn. That should leave a "fat" circle.

Libgdx circle with linewidth

1 Answers1