title: Draw a line in 3d using OpenTK
body: <p>I have the following code to create a line in 3d.</p>
  
  <pre><code>        GL.glClear(GL.GL_DEPTH_BUFFER_BIT | GL.GL_COLOR_BUFFER_BIT);
  
          GL.glMatrixMode(GL.GL_MODELVIEW);
          GL.glLoadIdentity();
  
          GL.glBegin(GL.GL_LINES);
          GL.glColor(Color.Brown);
          GL.glVertex3f(0,0,0);
          GL.glVertex3f(100,0,0);
          GL.glEnd();
  
          GL.glBegin(GL.GL_LINES);
          GL.glColor(Color.Brown);
          GL.glVertex3f(0, 0, 0);
          GL.glVertex3f(0, 100, 0);
          GL.glEnd();
  
          GL.glBegin(GL.GL_LINES);
          GL.glColor(Color.Yellow);
          GL.glVertex3f(0, 0, 0);
          GL.glVertex3f(0, 0, 10);
          GL.glEnd();
  
          SwapBuffers();
  </code></pre>
  
  <p>But when i run the program I only see the lines for the 1st 2... for the x and y axis whose value is 100.</p>
  
  <p>What is missing?</p>