title: GLUQuadric Disk drawn but fill color is not solid
body: <p>being a complete OpenGL newbie, I have a problem I do not understand how to solve. I am using JOGL, and trying to draw a disk, filled with a solid color and a different border color. My problem is obvious in the following image:</p>
  <p><img src="https://i.stack.imgur.com/IqKvj.jpg" alt="gluquadric disk" /></p>
  <p>What I cannot understand is why I can still see the lines produced by GLU. The code that draws this is the following:</p>
  <pre><code>glColor3ub(r, g, b); // purple
  gluDisk(quadric, 0, 50, 32, 2);
  
  glColor3ub(r, g, b); // dark gray
  gluDisk(quadric, 49, 50, 32, 2);
  </code></pre>
  <p>I suspect I have done something wrong with blending/anti-aliasing. When I disable anti-aliasing, the shape is drawn with solid color; however I need AA. I have set up AA and blending as shown below:</p>
  <pre><code>glEnable(GL2.GL_BLEND);
  glBlendFunc(GL2.GL_SRC_ALPHA, GL2.GL_ONE_MINUS_SRC_ALPHA);
  
  glEnable(GL2.GL_LINE_SMOOTH);
  glHint(GL2.GL_LINE_SMOOTH_HINT, GL2.GL_NICEST);
  
  glEnable(GL2.GL_POLYGON_SMOOTH);
  glHint(GL2.GL_POLYGON_SMOOTH_HINT, GL2.GL_NICEST);
  </code></pre>
  <p>Finally, my GLCanvas is created with the following GLCapabilities:</p>
  <pre><code>caps.setAlphaBits(16);
  caps.setDoubleBuffered(true);
  caps.setHardwareAccelerated(true);
  </code></pre>
  <p>Other than that, the Quadric rendering properties are the default. Does anybody understand what have I done wrong? I apologize for any information that might be missing! Thanks for reading!</p>
  <p>Ilias</p>