title: Where is this method called - (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
body: <p>Im just starting to look at Open GL ES for iOS and I'm looking through the source code on apples template code. The problem is both </p>
  
  <p><code>- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect</code> </p>
  
  <p>and </p>
  
  <p><code>- (void)update</code> </p>
  
  <p>are being called, but I'm unable to determine by what and how to change the frequency?</p>