title: Difference between single buffered(GLUT_SINGLE) and double buffered drawing(GLUT_DOUBLE)
body: <p>I'm using <a href="http://www.codemiles.com/c-opengl-examples/draw-3d-cube-using-opengl-t9018.html" rel="noreferrer">example here</a> it works under </p>
  
  <p><code>glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);</code></p>
  
  <p>but it become a transparent window when I set it to </p>
  
  <pre><code>glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
  </code></pre>
  
  <p>but I need that example work with some drawing under <code>GLUT_DOUBLE</code> mode.</p>
  
  <p>So what's the difference between <code>GLUT_DOUBLE</code> and <code>GLUT_SINGLE</code>?</p>