The GLKView class provides an OpenGL ES–based equivalent of the standard UIView drawing cycle. A GLKit View Draws OpenGL ES Content on Demand The GLKit framework also provides other features to ease OpenGL ES 2.0 and 3.0 development. As a result, you can focus your efforts primarily on your OpenGL ES rendering code and get your app up and running quickly. These classes extend the standard UIKit design patterns for drawing view content and managing view presentation. The GLKView class manages OpenGL ES infrastructure to provide a place for your drawing code, and the GLKViewController class provides a rendering loop for smooth animation of OpenGL ES content in a GLKit view. The GLKit framework provides view and view controller classes that eliminate the setup and maintenance code that would otherwise be required for drawing and animating OpenGL ES content. To create high-performance code on GPUs, use the Metal framework instead.
