title: Time model for glfwSwapBuffers
body: <blockquote>
    <p>This function sets the swap interval for the current context, i.e. the number of screen updates to wait before swapping the buffers of a window and returning from glfwSwapBuffers. This is sometimes called 'vertical synchronization', 'vertical retrace synchronization' or 'vsync'.</p>
  </blockquote>
  
  <p>Does this mean</p>
  
  <pre><code> ----------------------------------
   Generate next frame
   Wait until next frame is available
   ----------------------------------
  </code></pre>
  
  <p>that is, the period of the loop is independent on the computation task or</p>
  
  <pre><code> ----------------------------------
   Generate next frame
   Wait for 1/refresh_rate time units
   ----------------------------------
  </code></pre>
  
  <p>that is, the delay is added as extra time to perform the loop.</p>