Opentk/Source/Samples/iOS/ES11/OpenGLViewController.cs

using System;
using OpenTK;
using OpenTK.Graphics.ES20;
using OpenTK.Platform.iPhoneOS;
using Foundation;
using CoreAnimation;
using ObjCRuntime;
using OpenGLES;
using UIKit;

namespace ES11
{

    [Register("OpenGLViewController")]
    public partial class OpenGLViewController : UIViewController
    {
        public OpenGLViewController(IntPtr handle) : base(handle)
        {
        }

        new EAGLView View { get { return (EAGLView)base.View; } }

        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            
            NSNotificationCenter.DefaultCenter.AddObserver(UIApplication.WillResignActiveNotification, a =>
            {
                if (IsViewLoaded && View.Window != null)
                    View.StopAnimating();
            }, this);
            NSNotificationCenter.DefaultCenter.AddObserver(UIApplication.DidBecomeActiveNotification, a =>
            {
                if (IsViewLoaded && View.Window != null)
                    View.StartAnimating();
            }, this);
            NSNotificationCenter.DefaultCenter.AddObserver(UIApplication.WillTerminateNotification, a =>
            {
                if (IsViewLoaded && View.Window != null)
                    View.StopAnimating();
            }, this);
        }

        protected override void Dispose(bool disposing)
        {
            base.Dispose(disposing);
            
            NSNotificationCenter.DefaultCenter.RemoveObserver(this);
        }

        public override void DidReceiveMemoryWarning()
        {
            // Releases the view if it doesn't have a superview.
            base.DidReceiveMemoryWarning();
            
            // Release any cached data, images, etc that aren't in use.
        }

        public override void ViewWillAppear(bool animated)
        {
            base.ViewWillAppear(animated);
            View.StartAnimating();
        }

        public override void ViewWillDisappear(bool animated)
        {
            base.ViewWillDisappear(animated);
            View.StopAnimating();
        }
    }
}