private void RenderButton_Click(object sender, EventArgs e)
 {
     _stopFlag = false;
     var renderer = new Renderer();
     Scene scene = SpheresRadio.Checked ? SceneBuilder.Spheres() : SceneBuilder.GeometricFiguresBox();
     Stopwatch watch = Stopwatch.StartNew();
     renderer.Render(
         _drawTarget,
         scene,
         () =>
         {
             _display.Invalidate();
             Application.DoEvents();
             UpdateLabels();
         },
         RenderPasses,
         ref _stopFlag);
     watch.Stop();
     RenderTimeLabel.Text = string.Format("{0} min, {1} s, {2} ms", watch.Elapsed.Minutes, watch.Elapsed.Seconds,
         watch.Elapsed.Milliseconds);
 }