/// <summary>
 /// DrawProcessを新規に作り描画ループに追加する
 /// </summary>
 public void StartDraw()
 {
     if (isDrawing)
     {
         StopDraw();
     }
     isDrawing = true;
     CreateDrawProcess();
     DrawContext.AddDrawloop(DrawProcess, Properties.Resources.Shader);
     Form.Visible = true;
 }