绘制三角形

代码：

public partial class MainForm : Form
{
   public MainForm()
   {
       InitializeComponent();
       this.InitialDX();
   }

   private Device device = null;

   private void InitialDX()
   {
       PresentParameters presentParams = new PresentParameters();
       presentParams.Windowed = true;
       presentParams.SwapEffect = SwapEffect.Discard;

       device = new Device(
           0,
           DeviceType.Hardware,
           this,
           CreateFlags.SoftwareVertexProcessing,
           presentParams);
   }

   protected override void OnPaint(PaintEventArgs e)
   {
       base.OnPaint(e);
       this.DrawDX();
   }

   private void DrawDX()
   {
       if (this.device == null)
           return;

       this.device.Clear(ClearFlags.Target,
           Color.AliceBlue,
           1f,
           0);

       this.device.BeginScene();
       //绘制DX图形
       this.DrawMyGraphics();
       this.device.EndScene();

       this.device.Present();//显示图形
   }

   private void DrawMyGraphics()
   {
       CustomVertex.TransformedColored[] vertex =
           new CustomVertex.TransformedColored[3];

       vertex[0].Position = new Vector4(
           0,
           this.Height,
           0,
           0);
       vertex[0].Color = Color.Red.ToArgb();

       vertex[1].Position = new Vector4(
           this.Width / 2,
           0,
           0,
           0);
       vertex[1].Color = Color.Green.ToArgb();

       vertex[2].Position = new Vector4(
           this.Width,
           this.Height,
           0,
           0);
       vertex[2].Color = Color.Blue.ToArgb();

       this.device.VertexFormat = CustomVertex.TransformedColored.Format;
       this.device.DrawUserPrimitives(PrimitiveType.TriangleList,
           1,
           vertex);
   }
}

结果：

绘制三角形的代码主要在DrawMyGraphics中。需要注意的是顶点的索引是顺时针的，如果是逆时针，结果就没有三角形了，需要进行特殊设置。

device.RenderState.CullMode = Cull.None;