title: Pinch gesture for zoom and pan/tilt
body: <p>How do i use the <code>UIPinchGestureRecognizer</code> for multiple purposes? At the moment i am using it to zoom in/out of my GLKView, but i would like to use the gesture to move around (pan/tilt), but at the same time being able to zoom. I have seen this behaviour in many CAD and 3D App's on iOS.</p>
  
  <p>Code for pinching:</p>
  
  <pre><code>- (void)pinchDetected:(UIPinchGestureRecognizer *)pinchRecognizer
  {
      NSLog (@"%@", @"Pinching");
  
      if (pinchRecognizer.state == UIGestureRecognizerStateBegan ||
          pinchRecognizer.state == UIGestureRecognizerStateChanged ||
          pinchRecognizer.state == UIGestureRecognizerStateEnded) {
          _zoom += (-1)*(logf(pinchRecognizer.scale) * 10.0f);
          pinchRecognizer.scale = 1.0;
      }
  }
  </code></pre>