OpenGL(OpenTK)学习

绘制一个Cube
 public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void glControl1_Resize(object sender, EventArgs e)
        {
            //改变大小时触发的事件，在程序启动时将会触发一次
            GLControl c = sender as GLControl; //获取glControl1
            if (glControl1.ClientSize.Height == 0) //避免错误
                glControl1.ClientSize = new Size(glControl1.ClientSize.Width, 1);
            GL.Viewport(0, 0, glControl1.ClientSize.Width, glControl1.ClientSize.Height);
            //设置3D绘画的画布
            float aspect_ratio = Width / (float)Height;
            Matrix4 perpective = Matrix4.CreatePerspectiveFieldOfView(MathHelper.PiOver4, aspect_ratio, 1, 64);
            //设置4x4的变换矩阵
            GL.MatrixMode(MatrixMode.Projection);
            GL.LoadMatrix(ref perpective); //加载矩阵
        }

        private void glControl1_Paint(object sender, PaintEventArgs e)
        {
            //重绘事件，在刷新程序GUI时触发，在程序启动时将会触发一次
            Matrix4 lookat = Matrix4.LookAt(0, 5, 5, 0, 0, 0, 0, 1, 0);
            GL.MatrixMode(MatrixMode.Modelview);
            GL.LoadMatrix(ref lookat);
            //旋转变换，这是视图的调整
            GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
            //清空画布

            DrawCube();
            glControl1.SwapBuffers(); //清除缓存
        }

        protected override void OnLoad(EventArgs e) //重写Form.OnLoad
        {
            base.OnLoad(e); //触发原本的OnLoad
            GL.ClearColor(Color.White); //清空画布，并用Color.White填充画布
            GL.Enable(EnableCap.DepthTest); //深度测试
            glControl1_Resize(glControl1, EventArgs.Empty); //触发Resize事件
        }
        /*
         GL.Color3 => 设置顶点颜色GL.Vertex3 => 设置顶点位置
        GL.Begin(BeginMode.Quads) => Quads是多边形模式
        GL.End() => 用这个结束绘画
        这段代码看似为顶点着色，其实是因为Quads的影响让顶点内部填充了颜色。
        你们也许会觉得很奇怪，为什么上面的调用后面都有“3”呢？这是GL的形式：
        gl[过程名称][参数数量][参数类型](参数);
        //在OpenTk里就没有参数类型这个了，所以GL.Vertex3(...);在非OpenTK里就应该这样写glVertex3f(...);
        也就是说：GL.Vertex3后面将会传递3个参数
         * */
        private void DrawCube()
        {
            GL.Begin(BeginMode.Quads);
            GL.Color3(Color.Silver);
            GL.Vertex3(-1.0f, -1.0f, -1.0f);
            GL.Vertex3(-1.0f, 1.0f, -1.0f);
            GL.Vertex3(1.0f, 1.0f, -1.0f);
            GL.Vertex3(1.0f, -1.0f, -1.0f);
            GL.Color3(Color.Honeydew);
            GL.Vertex3(-1.0f, -1.0f, -1.0f);
            GL.Vertex3(1.0f, -1.0f, -1.0f);
            GL.Vertex3(1.0f, -1.0f, 1.0f);
            GL.Vertex3(-1.0f, -1.0f, 1.0f);
            GL.Color3(Color.Moccasin);
            GL.Vertex3(-1.0f, -1.0f, -1.0f);
            GL.Vertex3(-1.0f, -1.0f, 1.0f);
            GL.Vertex3(-1.0f, 1.0f, 1.0f);
            GL.Vertex3(-1.0f, 1.0f, -1.0f);
            GL.Color3(Color.IndianRed);
            GL.Vertex3(-1.0f, -1.0f, 1.0f);
            GL.Vertex3(1.0f, -1.0f, 1.0f);
            GL.Vertex3(1.0f, 1.0f, 1.0f);
            GL.Vertex3(-1.0f, 1.0f, 1.0f);
            GL.Color3(Color.PaleVioletRed);
            GL.Vertex3(-1.0f, 1.0f, -1.0f);
            GL.Vertex3(-1.0f, 1.0f, 1.0f);
            GL.Vertex3(1.0f, 1.0f, 1.0f);
            GL.Vertex3(1.0f, 1.0f, -1.0f);
            GL.Color3(Color.ForestGreen);
            GL.Vertex3(1.0f, -1.0f, -1.0f);
            GL.Vertex3(1.0f, 1.0f, -1.0f);
            GL.Vertex3(1.0f, 1.0f, 1.0f);
            GL.Vertex3(1.0f, -1.0f, 1.0f);
            GL.End();
        }

    }