title: Cannot create a Screenshot of a SCNView
body: <p>Is it possible to get a screenshot of an SCNView? I'm trying with the below code, but it always comes out white...</p>
  
  <pre><code>NSRect bounds = [window.contentView bounds];
  NSImage *screenshot = [[NSImage alloc] initWithData:[window.contentView dataWithPDFInsideRect:bounds]];
  </code></pre>
  
  <p>It works fine when the view is a standard NSView...</p>