public void progressbarDecrement()
        {
            renderer.render();
            Thread.Sleep(100);
            if (progressbar.Value > 0)
            {
                progressbar.Value -= 1;
            }
            else
            {
                return;
            }
            double progress = (double)progressbar.Value / (double)progressbar.Maximum;

            poly.tweening(points1, points2, progress, progressbarDecrement);
        }