BounceBall - XNA Farseer Magic

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace FarseerXNADemo3.Screens
{

    using Microsoft.Xna.Framework;
    using Microsoft.Xna.Framework.Content;
    using Microsoft.Xna.Framework.Graphics;
    using FarseerXNABase.ScreenSystem;
    using Microsoft.Xna.Framework.Input;

    public class InstructionsScreen : GameScreen
    {
        #region Properties & Variables

        private ContentManager _content;
        private Rectangle _viewport;

        private Texture2D _texture;
        #endregion

        #region Initialization and Load

        public InstructionsScreen()
        {
            TransitionOnTime = TimeSpan.FromSeconds(0.5);
            TransitionOffTime = TimeSpan.FromSeconds(0.5);

            this.IsPopup = true;
        }

        public override void LoadContent()
        {
            if (_content == null)
                _content = new ContentManager(ScreenManager.Game.Services, "Content");

            _texture = ScreenManager.ContentManager.Load<Texture2D>("instructions");

            UpdateScreen();
            ScreenManager.Camera.ProjectionUpdated += UpdateScreen;

            base.LoadContent();
        }

        public override void UnloadContent()
        {
            _content.Unload();
        }

        private void UpdateScreen()
        {
            Viewport viewport = ScreenManager.GraphicsDevice.Viewport;
            _viewport = new Rectangle(0, 0, viewport.Width, viewport.Height);
        }

        #endregion

        #region Game Methods

        public override void Update(GameTime gameTime, bool otherScreenHasFocus, bool coveredByOtherScreen)
        {
            // Allows popup to be closed by back button
            if (this.IsActive && GamePad.GetState(PlayerIndex.One).Buttons.Back == Microsoft.Xna.Framework.Input.ButtonState.Pressed)
            {
                this.ExitScreen();
            }

            base.Update(gameTime, otherScreenHasFocus, coveredByOtherScreen);
        }

        public override void Draw(GameTime gameTime)
        {
            ScreenManager.SpriteBatch.Begin();
            ScreenManager.SpriteBatch.Draw(_texture, new Vector2(_viewport.Width / 2 - _texture.Width / 2, _viewport.Height / 2 - _texture.Height / 2), Color.White);
            ScreenManager.SpriteBatch.End();
        }
        #endregion
    }

}