how to draw a rectangle in libgdx
private ShapeRenderer shapeRenderer;
// in create method:
shapeRenderer = new ShapeRenderer();
shapeRenderer.setAutoShapeType(true);
// in render method:
shapeRenderer.begin(ShapeRenderer.ShapeType.Filled);
shapeRenderer.setColor(Color.GREEN);
shapeRenderer.rect(x, y, width, height);
shapeRenderer.end();