GLKViewController for Sprite Rendering

using System;
using System.Drawing;

using MonoTouch.CoreFoundation;
using MonoTouch.UIKit;
using MonoTouch.Foundation;
using MonoTouch.GLKit;
using MonoTouch.OpenGLES;
using OpenTK.Graphics.ES20;
using OpenTK;

namespace XamarinSpriteAnimation.ViewControllers
{
    [Register("AnimationViewController")]
    public class AnimationViewController : GLKViewController
    {
        UIButton btnAnimation0;
        UIButton btnAnimation1;
        UIButton btnAnimation2;
        UIButton btnAnimation3;

        UIView buttonView;
        GLKView animationView;

        EAGLContext context;

        Sprite player;
        GLKBaseEffect effect;

        public AnimationViewController()
        {

        }

        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 ViewDidLoad()
        {
            base.ViewDidLoad();

            View = new UIView();
            View.Frame = new RectangleF(0, 0, UIScreen.MainScreen.Bounds.Width, UIScreen.MainScreen.Bounds.Height);

            #region Create GLKView
            context = new EAGLContext(EAGLRenderingAPI.OpenGLES2);

            if (context == null)
                Console.WriteLine("Failed to create ES context...");

            animationView = new GLKView(new RectangleF(UIScreen.MainScreen.Bounds.Width * 0.05f,
                                              UIScreen.MainScreen.Bounds.Height * 0.05f,
                                              UIScreen.MainScreen.Bounds.Width * 0.9f,
                                              UIScreen.MainScreen.Bounds.Height * 0.75f), context);

            EAGLContext.SetCurrentContext(context);

            animationView.DrawInRect += new EventHandler<GLKViewDrawEventArgs>(animationView_DrawInRect);

            View.AddSubview(animationView);
            #endregion

            #region Create Buttons & Button View
            buttonView = new UIView();
            buttonView.Frame = new RectangleF(UIScreen.MainScreen.Bounds.Width * 0.05f,
                                              UIScreen.MainScreen.Bounds.Height * 0.85f,
                                              UIScreen.MainScreen.Bounds.Width * 0.9f,
                                              UIScreen.MainScreen.Bounds.Height * 0.1f);

            btnAnimation0 = UIButton.FromType(UIButtonType.RoundedRect);
            btnAnimation0.Frame = new RectangleF(buttonView.Frame.Width * 0.0f,
                                              buttonView.Frame.Height * 0.0f,
                                              buttonView.Frame.Width * 0.25f,
                                              buttonView.Frame.Height * 1.0f);
            btnAnimation0.SetTitle("One", UIControlState.Normal);

            btnAnimation0.AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleTopMargin |
                UIViewAutoresizing.FlexibleBottomMargin;

            buttonView.AddSubview(btnAnimation0);

            btnAnimation1 = UIButton.FromType(UIButtonType.RoundedRect);
            btnAnimation1.Frame = new RectangleF(buttonView.Frame.Width * 0.25f,
                                              buttonView.Frame.Height * 0.0f,
                                              buttonView.Frame.Width * 0.25f,
                                              buttonView.Frame.Height * 1.0f);
            btnAnimation1.SetTitle("Two", UIControlState.Normal);

            btnAnimation1.AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleTopMargin |
                UIViewAutoresizing.FlexibleBottomMargin;

            buttonView.AddSubview(btnAnimation1);

            btnAnimation2 = UIButton.FromType(UIButtonType.RoundedRect);
            btnAnimation2.Frame = new RectangleF(buttonView.Frame.Width * 0.5f,
                                              buttonView.Frame.Height * 0.0f,
                                              buttonView.Frame.Width * 0.25f,
                                              buttonView.Frame.Height * 1.0f);
            btnAnimation2.SetTitle("Three", UIControlState.Normal);

            btnAnimation2.AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleTopMargin |
                UIViewAutoresizing.FlexibleBottomMargin;

            buttonView.AddSubview(btnAnimation2);

            btnAnimation3 = UIButton.FromType(UIButtonType.RoundedRect);
            btnAnimation3.Frame = new RectangleF(buttonView.Frame.Width * 0.75f,
                                              buttonView.Frame.Height * 0.0f,
                                              buttonView.Frame.Width * 0.25f,
                                              buttonView.Frame.Height * 1.0f);
            btnAnimation3.SetTitle("Four", UIControlState.Normal);

            btnAnimation3.AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleTopMargin |
                UIViewAutoresizing.FlexibleBottomMargin;

            buttonView.AddSubview(btnAnimation3);

            View.AddSubview(buttonView);
            #endregion

            #region Create Player
            effect = new GLKBaseEffect();
            Matrix4 projectionMatrix = Matrix4.CreateOrthographicOffCenter(0, animationView.Frame.Width, 0, animationView.Frame.Height, -1024, 1024);
            effect.Transform.ProjectionMatrix = projectionMatrix;
            player = new Sprite(@"Player.png", effect);
            #endregion
        }

        void animationView_DrawInRect(object sender, GLKViewDrawEventArgs e)
        {
            GL.ClearColor(0.98f, 0.98f, 0.98f, 1.0f);
            //GL.Clear((uint)(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit));
            GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
            GL.BlendFunc(BlendingFactorSrc.SrcAlpha, BlendingFactorDest.OneMinusSrcAlpha);
            GL.Enable(EnableCap.Blend);

            player.Render();
        }
    }
}