title: How to use glOrtho() in OpenGL?
body: <p>I can't understand the usage of <code>glOrtho</code>. Can someone explain what it is used for?</p>
  
  <p>Is it used to set the range of x y and z coordinates limit?</p>
  
  <pre><code>glOrtho(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0);
  </code></pre>
  
  <p>It means that the x, y and z range is from -1 to 1?</p>