title: Is there a CADisplayLink equivalent for macos/cocoa/opengl?
body: <p>I've discovered <a href="http://developer.apple.com/library/ios/#documentation/QuartzCore/Reference/CADisplayLink_ClassRef/Reference/Reference.html" rel="noreferrer">CADisplayLink</a> for IOS 3.1+ which triggers events when the display has been refreshed, effectively allowing you to synchronise with display updates without having to use NSTimer.</p>
  
  <p>Is there an equivalent for timing when writing opengl applications under macos/cocoa?</p>