2, two examples: triangular geometric transformation translation (Translate), rotation (Scale), scaling (Rotate)

namespace sharpGLTest02
{
    public partial class Form1 : Form
    {
        private int mtype = 3;
        public Form1()
        {
            InitializeComponent();
        }

        //初始化
        private void openGLControl1_OpenGLInitialized(object sender, EventArgs e)
        {

        }
        //调整
        private void openGLControl1_Resize(object sender, EventArgs e)
        {

        }
        //画图
        private void openGLControl1_OpenGLDraw(object sender, PaintEventArgs e)
        {
            SharpGL.OpenGL gl = this.openGLControl1.OpenGL;

            gl.ClearColor(0, 0, 0, 1);
            //清除深度缓存 
            gl.Clear(OpenGL.GL_COLOR_BUFFER_BIT | OpenGL.GL_DEPTH_BUFFER_BIT);

            switch (mtype)
            {
                case 0:
                    translateSample(gl);
                    break;
                case 1:
                    rotateSample(gl);
                    break;
                case 2:
                    scaleSample(gl);
                    break;
                case 3:
                    originSample(gl);
                    break;
            }
            gl.Finish();
            gl.Flush(); //强制刷新
        }
        private void originSample(SharpGL.OpenGL gl)
        {
            gl.LoadIdentity();
            gl.Translate(0f, 0f, -1f);
            drawPT(gl);

            //gl.LoadIdentity();
            //gl.Translate(0f, 1f, -1f);
            //drawPT(gl);
        }

        private void scaleSample(SharpGL.OpenGL gl)
        {
            gl.LoadIdentity();
            //缩放
            //gl.Scale(1f, 1f, 1f);
            gl.Scale(1f, 2f, 1f);
            gl.Translate(0, 0, -9f);
            drawPT(gl);

            gl.LoadIdentity();
            gl.Scale(5f, 1f, 1f);
            //gl.Translate(0, 1, -9f);
            gl.Translate(0, 2, -9f);
            drawPT(gl);
        }

        private void rotateSample(SharpGL.OpenGL gl)
        {
            gl.LoadIdentity();
            //旋转
            gl.Rotate(0,0, 45);
            gl.Translate(0, 0, -3f);
            drawPT(gl);

            //gl.Rotate(0, 0, 45);
            //gl.Translate(-1, 1,0f);
            //drawPT(gl);
        }

        private void translateSample(SharpGL.OpenGL gl)
        {
            //Reset the current specified matrix is an identity matrix, the origin of the current user coordinate system is moved to the center of the screen 
            gl.LoadIdentity ();
             // Since gl.LoadIdentity (); converting point to the origin, the coordinate axis conversion to the position ( 0, 0, -3), and this was noted above relative to (0,0,0) point positioning 
            gl.Translate (0F, 0F, - 3F); 
            drawPT (GL); 

            gl.LoadIdentity (); 
            // GL. Translate (0F, 0.5f, -3F); 
            gl.Translate (0F, 1F, - 3F);
             // gl.Translate (0F, 1.5F, -3F); 
            drawPT (GL); 
        } 

        Private  void drawPT (SharpGL. GL the OpenGL) 
        { 
            gl.PointSize (5F); 
            gl.Begin (OpenGL.GL_TRIANGLES); 
            { 
                gl.Vertex (0.0f , 0F, 0.0f ); 
                gl.Vertex ( - 1.0f , -1F, 0.0f ); 
                gl.Vertex ( 1.0f , -1F, 0.0f ); 
            } 
            gl.End (); 
        } 

        // button clicks event 
        Private  void btnTranslate_Click ( Object SENDER, EventArgs E) 
        { 
            Switch (((the Button) SENDER) .Name) 
            { 
                Case  " btnTranslate " : 
                    MTYPE = 0 ;
                     BREAK;
                case "btnRotate":
                    mtype = 1;
                    break;
                case "btnScale":
                    mtype = 2;
                    break;
                case "btnOrigin":
                    mtype = 3;
                    break;
            }
        }
        
    }
}