private void Test_MouseDown(object sender, OpenTK.Input.MouseButtonEventArgs e)
{
if (e.Mouse.LeftButton == OpenTK.Input.ButtonState.Pressed)
{
list.Add(new Point2D(e.Mouse.X, e.Mouse.Y));
if (list.Count == 4)
{
GeometryTool.AddQuat(list);
}
}
}