This chapter is not designed to teach you OpenGL. If you want to learn OpenGL, read The OpenGL Programming Guide. This chapter is intended to show you how to do drawing with OpenGL in an application that is written using Cocoa. Like all other drawing in Cocoa, OpenGL rendering will be done in a view. Until now, all of your views have used an
NSGraphicsContext to do drawing with Quartz (via
NSOpenGLView is a subclass of
NSView that has an OpenGL drawing context. Just as you needed the focus locked on a view to do drawing with Quartz, so the OpenGL drawing context must be active for any OpenGL drawing commands to have an effect.
Here are some important methods in