You’ll learn how all of this works in this GLKit tutorial for iOS. It also allows developers to focus on drawing, not on getting the project set up. Apple has developed a framework called GLKit to help developers create apps that leverage OpenGL and to abstract boilerplate code.
If you’re interested in graphics programming, chances are that you’ve read about OpenGL, which remains the most-adopted API from a hardware and software perspective. The original tutorial was written by Ray Wenderlich. Update note: This tutorial has been updated to Swift 4.1 and Xcode 9.3 by Felipe Laso-Marsetti.