CAEAGLLayer class supports drawing OpenGL content in iPhone applications. If you plan to use OpenGL for your rendering, use this class as the backing layer for your views by returning it from your view’s
layerClass class method. The returned
CAEAGLLayer object is a wrapper for a Core Animation surface that is fully compatible with OpenGL ES function calls.
Available in iOS 2.0 and later.
The properties of the native windowing surface.
@property(copy) NSDictionary *drawableProperties
You can use this property to change the underlying color format for the windowing surface and whether or not the surface retains its contents. For a list of keys (and corresponding values) you can include in this dictionary (along with their default values), see the EAGLDrawable Protocol Reference.