Game1.cs

using System;
using FarseerPhysics;
using FarseerPhysics.Dynamics;
using FarseerPhysics.Factories;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using TestPhysics.Physics;

namespace TestPhysics {
    /// <summary>
    /// This is the main type for your game.
    /// </summary>
    public class Game1 : Game {
        private GraphicsDeviceManager graphics;
        private SpriteBatch spriteBatch;
        private World world;
        private DebugViewXNA debugView;
        private Camera2D camera;

        public Game1() {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
        }

        /// <summary>
        /// Allows the game to perform any initialization it needs to before starting to run.
        /// This is where it can query for any required services and load any non-graphic
        /// related content.  Calling base.Initialize will enumerate through any components
        /// and initialize them as well.
        /// </summary>
        protected override void Initialize() {
            // TODO: Add your initialization logic here

            base.Initialize();
        }

        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent() {
            // Create a new SpriteBatch, which can be used to draw textures.
            spriteBatch = new SpriteBatch(GraphicsDevice);

            // TODO: use this.Content to load your game content here
            world = new World(new Vector2(0.0f, 1.0f));

            var floor = BodyFactory.CreateRectangle(world, 15.0f, 1.0f, 1.0f);
            floor.Position = new Vector2(0.0f, 3.0f);

            for (var i = 0; i < 5; i++) {
                var rect = BodyFactory.CreateRectangle(world, 0.5f, 0.5f, 1.0f);
                rect.BodyType = BodyType.Dynamic;
                rect.Position = new Vector2(0.0f, -5.0f);
                rect.Restitution = 1.0f;
            }
            
            debugView = new DebugViewXNA(world);
            debugView.AppendFlags(DebugViewFlags.Shape);
            debugView.AppendFlags(DebugViewFlags.PolygonPoints);
            debugView.DefaultShapeColor = Color.White;
            debugView.SleepingShapeColor = Color.LightGray;
            debugView.LoadContent(GraphicsDevice, Content);

            camera = new Camera2D(GraphicsDevice) {Zoom = 0.5f};
        }

        /// <summary>
        /// UnloadContent will be called once per game and is the place to unload
        /// game-specific content.
        /// </summary>
        protected override void UnloadContent() {
            // TODO: Unload any non ContentManager content here
        }

        /// <summary>
        /// Allows the game to run logic such as updating the world,
        /// checking for collisions, gathering input, and playing audio.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Update(GameTime gameTime) {
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed || Keyboard.GetState().IsKeyDown(Keys.Escape))
                Exit();

            // TODO: Add your update logic here
            world.Step(Math.Min((float)gameTime.ElapsedGameTime.TotalSeconds, (1f / 30f)));
            camera.Update(gameTime.TotalGameTime);

            base.Update(gameTime);
        }

        /// <summary>
        /// This is called when the game should draw itself.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Draw(GameTime gameTime) {
            GraphicsDevice.Clear(Color.CornflowerBlue);

            // TODO: Add your drawing code here
            debugView.RenderDebugData(ref camera.SimProjection, ref camera.SimView);

            base.Draw(gameTime);
        }
    }
}