[Csgl-users] Trouble with CsGL and rotating.

[Michael S. <msh...@wa...>]

  I am writing an app in C# (VS.NET). I am using CsGL for some basic OpenGL stuff. I want to draw an x,y, and z axes in the control, and then rotate the view so that it looks 3D - if you draw the axes and don't rotate them, you wouldn't be able to see the Z axis.

  Here's my code, which I based mainly on (http://www.componentsnotebook.com/notebooks/csharp/csgl.aspx). You will see that I called GL.glRotatef(10.0f, 1.0f, 1.0f, 0.0f); at one point. I picked 1.0 for the angle arbitrarily; however, no matter what angle I choose, it only seems to make the axes smaller. Please help, and if there are any questions ask away!

  Btw, this is how the axes look before I rotate: http://www.terptrader.com/normalaxis.png
  And after I rotate: http://www.terptrader.com/rotatedaxis.png
  My goal is to have the axes look 3D, like in this picture: http://wonkosite.ausbone.net/vrml/axis.gif



  If you could help I would really appreciate it because I am completely stumped right now.



              private void drawAxis()

              {

                    double left = 0.05 * Size.Width;

                    double right = 0.95 * Size.Width;

                    double bottom = 0.05 * Size.Height;

                    double top = 0.95 * Size.Height;

                    double origin_x = Size.Width / 2;

                    double origin_y = Size.Height / 2;



                    // draw X axis

                    GL.glBegin( GL.GL_LINES );

                    GL.glVertex3d( left, origin_x, 0 );

                    GL.glVertex3d( right, origin_x, 0 );

                    GL.glEnd();



                    // draw Y axis

                    GL.glBegin( GL.GL_LINES );

                    GL.glVertex3d( origin_y, bottom, 0 );

                    GL.glVertex3d( origin_y, top, 0 );

                    GL.glEnd();



                    // draw Z axis

                    GL.glBegin( GL.GL_LINES );

                    GL.glVertex3d( origin_x, origin_y, 0.0 );

                    GL.glVertex3d( origin_x, origin_y, 1.0 );

                    GL.glEnd();



                    GL.glFlush();

              }



              public override void glDraw()

              {

                    GL.glRotatef(0.5f, 0.0f, 1.0f, 0.0f);

                    drawAxis();

              }



              protected override void InitGLContext()

              {

                    GL.glClearColor( 1.0f, 1.0f, 1.0f, 0.0f );

                    GL.glColor3f( 0.0f, 0.0f, 0.0f );

                    GL.glPointSize( 4.0f );

              }





              protected override void OnSizeChanged(EventArgs e)

              {

                    base.OnSizeChanged(e);



                    GL.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);                                          // Clear Screen And Depth Buffer

                    GL.glMatrixMode(GL.GL_PROJECTION);

                    GL.glLoadIdentity();

                    GL.glOrtho( 0.0, Size.Width, 0.0, Size.Height, 1.0, -1.0 );

                    GL.glMatrixMode(GL.GL_MODELVIEW);

              }