Вы можете нарисовать прямоугольник с помощью ShapeRenderer:
private ShapeRenderer shapeRenderer;
private Rectangle rectangle;
@Override
public void show() {
shapeRenderer = new ShapeRenderer();
rectangle = new Rectangle(0,0,10,10);
}
@Override
public void render(float delta) {
shapeRenderer.begin();
shapeRenderer.rect(rectangle.getX(), rectangle.getY(), rectangle.getWidth(), rectangle.getHeight());
shapeRenderer.end();
}
@Override
public void dispose() {
shapeRenderer.dispose();
}