title: How to capture a OpenGL view as UIImage?
body: <p>When I try to use <a href="https://stackoverflow.com/questions/3129352/need-to-capture-uiview-into-a-uiimage-including-all-subviews">this method</a> to convert a OpenGL view to UIImage, only the view's background is returned, but not the GLView content. How can I convert OpenGL's context into a UIImage?</p>