Drawing is not working correctly after creating CompoundPolygon

iOS
1

I have created a MonoGame iOS solution in Xamarin Studio. After that, I added Farseer Physics Engine to my solution. My project is a simple GameState management. I try to load and unload stuff. Everything seems to work, except creating a Farseer CompoundPolygon. After creating a Farseer CompoundPolygon, the Farseer Debug View is no more drawing the Farseer shapes. In addition, sprites(for example the file Settingsbackground) are not drawn on the screen. I get no error messages and the game is not freezing, it still runs(I checked it with breakpoints), but nothing from the Settings class gets drawn after creating a Farseer CompoundPolygon. There must be a problem with Farseer CompoundPolygon, because everything works if I don’t create a CompoundPolygon.

What is wrong with my project? Is this a bug in the Farseer Physics Engine or am I doing something wrong?

Should I change the way I load/unload content?

I have uploaded my project here: Dropbox - File Deleted - Simplify your life

In this picture, drawing is not working correctly because I’m already in the Settings GameState and I have created a Farseer CompoundPolygon. But the file Settingsbackground and the Farseer Debug View are not drawn.

Game1.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Input.Touch;
using Microsoft.Xna.Framework.Media;
using FarseerPhysics.Dynamics;
using FarseerPhysics.Factories;
using FarseerPhysics.Common;
using FarseerPhysics.Common.Decomposition;
using FarseerPhysics.Common.PolygonManipulation;
using FarseerPhysics.DebugView;

namespace iPhoneGamestates
{
public class Game1 : Game
{
GraphicsDevice graphicsdevice;
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;

public Body Polygon;
public float PolygonScale;
public Vector2 PolygonOrigin;
public List<Vertices> Polygonlist = new List<Vertices>();
public Texture2D PolygonSprite;

public Camera camera;
public Vector2 vp, gameWorldSize = new Vector2(1334, 750);
public float ScaleX, ScaleY, Scale;
Vector2 Newcameraposition;

public bool Draw_debugView = false;
public DebugViewXNA physicsDebug;
public World world;
public Body Ball;
public Texture2D BallSprite;
public bool UpdateFarseerWorld = false;

public Texture2D Menubackground, Introbackground, Settingsbackground;
public float delta;
public bool NextGameState = false, Settingscreenactivated = false;
IState lastState, currentState, savelastState;

public ContentManager SettingsContent;
public ContentManager IntroContent;
public ContentManager MenuContent;

public enum GameStates
{
    IntroState = 0,
    MenuState = 1,
    SettingsState = 2
}

public void ChangeGameState(GameStates newState)
{
    if (newState == currentGameState)
        return;
    lastGameState = currentGameState;
    lastState = currentState;
    switch (newState)
    {
        case GameStates.IntroState:
            currentState = new Intro(this, GraphicsDevice);
            currentGameState = GameStates.IntroState;
            break;
        case GameStates.MenuState:
            currentState = new Menu(this, GraphicsDevice);
            currentGameState = GameStates.MenuState;
            if (IntroContent != null)
                IntroContent.Unload();  
            if (SettingsContent != null)
                SettingsContent.Unload();
            break;                              
        case GameStates.SettingsState:
            currentState = new Settings(this, GraphicsDevice);
            currentGameState = GameStates.SettingsState;
            break;

    }
    currentState.Load(Content);
}

public void ChangeToLastandCurrent()
{
    savelastGameState = currentGameState;
    currentGameState = lastGameState;
    lastGameState = savelastGameState;
    savelastState = currentState;
    currentState = lastState;
    lastState = savelastState;
}

public GameStates CurrentState
{
    get { return currentGameState; }
    set { currentGameState = value; }
}

public GameStates LastState
{
    get { return lastGameState; }
    set { lastGameState = value; }
}

private GameStates currentGameState;
private GameStates lastGameState;
private GameStates savelastGameState;

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

protected override void Initialize()
{
    currentState = new Intro(this, graphicsdevice);
    currentGameState = GameStates.IntroState;

    base.Initialize();
}

protected override void UnloadContent()
{
    Content.Unload();
}

public void IntroLoad()
{
    Introbackground = IntroContent.Load<Texture2D>("Content/Introbackground");
}

public void SettingsLoad()
{
    Settingsbackground = SettingsContent.Load<Texture2D>("Content/Settingsbackground");     

    if (world == null)
    {
        world = new World(new Vector2(0, 7));
    }
    else
    {
        world.Clear();
        world = new World(new Vector2(0, 7));
    }
    UpdateFarseerWorld = true;

    physicsDebug = new DebugViewXNA(world);
    physicsDebug.DefaultShapeColor = Color.White;
    physicsDebug.SleepingShapeColor = Color.LightGray;
    physicsDebug.LoadContent(GraphicsDevice, Content);

    Draw_debugView = true;

    BallSprite = SettingsContent.Load<Texture2D>("Content/Ball");

    Ball = BodyFactory.CreateCircle(world, 0.25f, 1.0f);
    Ball.BodyType = BodyType.Static;
    Ball.Position = new Vector2(6.4f, 3f);
    Ball.IsSensor = false;
    Ball.Restitution = 0.4f;
    Ball.CollisionCategories = Category.Cat30;

    PolygonSprite = SettingsContent.Load<Texture2D>("Content/Ground");

    uint[] polygondata = new uint[PolygonSprite.Width * PolygonSprite.Height];
    PolygonSprite.GetData(polygondata);
    Vertices polygontextureVertices = PolygonTools.CreatePolygon(polygondata, PolygonSprite.Width, false);
    Vector2 polygoncentroid = -polygontextureVertices.GetCentroid();
    polygontextureVertices.Translate(ref polygoncentroid);
    PolygonOrigin = -polygoncentroid;
    polygontextureVertices = SimplifyTools.ReduceByDistance(polygontextureVertices, 4f);
    Polygonlist = Triangulate.ConvexPartition(polygontextureVertices, TriangulationAlgorithm.Bayazit);
    PolygonScale = 1f;
    Vector2 polygonvertScale = new Vector2(ConvertUnits.ToSimUnits(1)) * PolygonScale;
    foreach (Vertices polygonvertices in Polygonlist)
    {
        polygonvertices.Scale(ref polygonvertScale);
    }

    Polygon = BodyFactory.CreateCompoundPolygon(world, Polygonlist, 1.0f, BodyType.Dynamic);
    Polygon.BodyType = BodyType.Static;
    Polygon.IsSensor = false;
    Polygon.Position = new Vector2(6f, 4.5f);
    Polygon.Rotation = 0f;
    Polygon.Restitution = 0.05f;
    Polygon.CollisionCategories = Category.Cat25;
}

public void MenuLoad()
{
    Menubackground = MenuContent.Load<Texture2D>("Content/Menubackground");
}

protected override void LoadContent()
{
    spriteBatch = new SpriteBatch(GraphicsDevice);
    vp = new Vector2(GraphicsDevice.Viewport.Width, GraphicsDevice.Viewport.Height);

    ScaleX = vp.X / gameWorldSize.X;
    ScaleY = vp.Y / gameWorldSize.Y;
    Scale = Math.Min(ScaleX, ScaleY);

    camera = new Camera(new Vector2(gameWorldSize.X / 2, gameWorldSize.Y / 2), Scale, vp);

    currentState.Load(Content);

    TouchPanel.EnabledGestures = GestureType.Tap;
}

protected override void Update(GameTime gameTime)
{
    delta = (float)gameTime.ElapsedGameTime.TotalSeconds;

    if ((UpdateFarseerWorld == true) && (world != null))
        world.Step(Math.Min(delta, (1f / 60f)));

    Newcameraposition = new Vector2(gameWorldSize.X / 2, gameWorldSize.Y / 2);

    camera.Update(gameTime, Newcameraposition, Scale, vp);

    while (TouchPanel.IsGestureAvailable)
    {
        GestureSample gs = TouchPanel.ReadGesture();
        switch (gs.GestureType)
        {
            case GestureType.Tap:                       
                NextGameState = true;
            break;
        }
    }

    if ((lastGameState == GameStates.MenuState) && (currentGameState == GameStates.SettingsState))
    {
        lastState.Update(gameTime);
    }

    currentState.Update(gameTime);

    base.Update(gameTime);
}

protected override void Draw(GameTime gameTime)
{
    graphics.GraphicsDevice.Clear(Color.CornflowerBlue);

    spriteBatch.Begin(SpriteSortMode.BackToFront, BlendState.AlphaBlend, null, null, null, null, camera.GetMatrix());
      if ((lastGameState == GameStates.MenuState) && (currentGameState == GameStates.SettingsState))
      {
        lastState.Render(spriteBatch);
      }

      currentState.Render(spriteBatch);
    spriteBatch.End();

    if (Draw_debugView == true)
    {
        float zoom = Scale;
        float width = (1f / zoom) * ConvertUnits.ToSimUnits(GraphicsDevice.Viewport.Width);
        float height = (-1f / zoom) * ConvertUnits.ToSimUnits(GraphicsDevice.Viewport.Height);
        float zNearPlane = 0f;
        float zFarPlane = 1000000f;
        Matrix projection = Matrix.CreateOrthographic(width, height, zNearPlane, zFarPlane);

        float xTranslation = -1 * ConvertUnits.ToSimUnits(camera.PlayerPosition.X);
        float yTranslation = -1 * ConvertUnits.ToSimUnits(camera.PlayerPosition.Y);
        Vector3 translationVector = new Vector3(xTranslation, yTranslation, 0f);
        Matrix view = Matrix.Identity;
        view.Translation = translationVector;

        physicsDebug.RenderDebugData(ref projection, ref view);
    }

    base.Draw(gameTime);
}

}
}

Intro.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Input.Touch;
using Microsoft.Xna.Framework.Media;

namespace iPhoneGamestates
{
public class Intro : IState
{
private Game1 game1;
GraphicsDevice graphicsDevice;
float Count = 5f;
bool ChangeGameState = true;

public Intro(Game1 game, GraphicsDevice device)
{
    game1 = game;
    graphicsDevice = device;
    game1.IntroContent = new ContentManager(game1.Services);
}

public void Load(ContentManager content)
{
    game1.IntroLoad();
}

public void Update(GameTime gametime)
{
    Count -= game1.delta;
    if ((Count < 0) && (ChangeGameState == true))
    {
        ChangeGameState = false;
        game1.ChangeGameState(Game1.GameStates.MenuState);
    }
}
public void Render(SpriteBatch batch)
{
    batch.Draw(game1.Introbackground, new Rectangle((int)game1.gameWorldSize.X / 2, (int)game1.gameWorldSize.Y / 2, game1.Introbackground.Width, game1.Introbackground.Height), null, Color.White, 0, new Vector2(game1.Introbackground.Width / 2, game1.Introbackground.Height / 2), SpriteEffects.None, 0.10f);
}

}
}

Menu.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Input.Touch;
using Microsoft.Xna.Framework.Media;
using FarseerPhysics.Dynamics;
using FarseerPhysics.Factories;
using FarseerPhysics.Common;
using FarseerPhysics.DebugView;

namespace iPhoneGamestates
{
public class Menu : IState
{
private Game1 game1;
GraphicsDevice graphicsDevice;

public Menu(Game1 game, GraphicsDevice device)
{
    game1 = game;
    graphicsDevice = device;
    game1.MenuContent = new ContentManager(game1.Services);
}

public void Load(ContentManager content)
{           
    game1.MenuLoad();
}

public void Update(GameTime gametime)
{
    if ((game1.NextGameState == true) && (game1.Settingscreenactivated == false))
    {
        game1.NextGameState = false;
        game1.Settingscreenactivated = true;
        game1.ChangeGameState(Game1.GameStates.SettingsState);
    }
}

public void Render(SpriteBatch batch)
{           
    batch.Draw(game1.Menubackground, new Rectangle((int)game1.gameWorldSize.X / 2, (int)game1.gameWorldSize.Y / 2, game1.Menubackground.Width, game1.Menubackground.Height), null, Color.White, 0, new Vector2(game1.Menubackground.Width / 2, game1.Menubackground.Height / 2), SpriteEffects.None, 0.10f);
}

}

}

Settings.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Input.Touch;
using Microsoft.Xna.Framework.Media;
using FarseerPhysics.Dynamics;
using FarseerPhysics.Factories;
using FarseerPhysics.Common;

namespace iPhoneGamestates
{
public class Settings : IState
{

private Game1 game1;

GraphicsDevice graphicsDevice;

public Settings(Game1 game, GraphicsDevice device)
{
    game1 = game;
    graphicsDevice = device;
    game1.SettingsContent = new ContentManager(game1.Services);
}

public void Load(ContentManager content)
{
    game1.SettingsLoad();
}

public void Update(GameTime gametime)
{
    if (game1.NextGameState == true)
    {
        game1.NextGameState = false;
        game1.UpdateFarseerWorld = false;
        game1.Draw_debugView = false;
        game1.Settingscreenactivated = false;
        game1.ChangeGameState(Game1.GameStates.MenuState);
    }

}

public void Render(SpriteBatch batch)
{
    batch.Draw(game1.Settingsbackground, new Rectangle((int)game1.gameWorldSize.X / 2, (int)game1.gameWorldSize.Y / 2, game1.Settingsbackground.Width, game1.Settingsbackground.Height), null, Color.White, 0, new Vector2(game1.Settingsbackground.Width / 2, game1.Settingsbackground.Height / 2), SpriteEffects.None, 0.09f);

    batch.Draw(game1.PolygonSprite, ConvertUnits.ToDisplayUnits(game1.Polygon.Position),
               null, Color.White, game1.Polygon.Rotation, new Vector2(game1.PolygonSprite.Width / 2.0f, game1.PolygonSprite.Height / 2.0f), game1.PolygonScale, SpriteEffects.None,
                                      0.05f);

    batch.Draw(game1.BallSprite, ConvertUnits.ToDisplayUnits(game1.Ball.Position),                                                      null,
               Color.White, game1.Ball.Rotation, new Vector2(game1.BallSprite.Width / 2.0f, game1.BallSprite.Height / 2.0f), 1f,
                                                SpriteEffects.None, 0.04f);
}

}
}

2

I use compound polygons in my project without problems so its likely a camera, position or unit conversion error somewhere.

Im also not sure what you’re doing with the rendering of the debug view.

I draw the farseer debug view like this:
DebugView.RenderDebugData(ref SimProjection, ref SimView);

3

But the debug view is working correctly for other shapes, for example a circle. If I don’t create the compound polygon, then it works because everything is drawn on the screen.
I have not changed the code to create this picture, I just removed the compound polygon code.

Could you show me how you create your compound polygon?

4

Actually, it looks like you’re creating compound polygon from texture data. This doesn’t work correctly on iOS/Android in my experience. You need to manually create the polygon shapes from verts.

Might also be worth trying to create just one of them for testing until you find the problem rather than making a list of them.

5

How can I manually create the polygon shapes from verts? How should I create the polygon on iOS/Android?

6

Heres an example of a rectangle as a compound polygon, I mostly use it to create different ramps and hill shapes (triangles):

            Vertices vertices = new Vertices(4);
            vertices.Add(new Vector2(ConvertUnits.ToSimUnits(position.X), ConvertUnits.ToSimUnits(position.Y + 48)));
            vertices.Add(new Vector2(ConvertUnits.ToSimUnits(position.X + 64), ConvertUnits.ToSimUnits(position.Y)));
            vertices.Add(new Vector2(ConvertUnits.ToSimUnits(position.X - 24), ConvertUnits.ToSimUnits(position.Y + 48)));
            vertices.Add(new Vector2(ConvertUnits.ToSimUnits(position.X - 24), ConvertUnits.ToSimUnits(position.Y)));

            verts = new List<Vertices>(1);
            verts.Add(vertices);

            polygonShape = BodyFactory.CreateCompoundPolygon(world, verts, 0.1f);

            polygonShape.CollisionCategories = Category.Cat4;
            polygonShape.CollidesWith = Category.Cat5;

Polygon from texture does work on Windows or at least it did last time I tried but I ended up making my own shapes like above for iOS and Android.

7

Thanx for the example.
I found out how to create compound polygons from textures on iOS. You need to do this part in „protected override void LoadContent()“ instead of doing it in „public void SettingsLoad()“.

                PolygonSprite = Content.Load<Texture2D>("Ground");

  	uint[] polygondata = new uint[PolygonSprite.Width * PolygonSprite.Height];
  	PolygonSprite.GetData(polygondata);
  	Vertices polygontextureVertices = PolygonTools.CreatePolygon(polygondata, PolygonSprite.Width, false);
  	Vector2 polygoncentroid = -polygontextureVertices.GetCentroid();
  	polygontextureVertices.Translate(ref polygoncentroid);
  	PolygonOrigin = -polygoncentroid;
  	polygontextureVertices = SimplifyTools.ReduceByDistance(polygontextureVertices, 4f);
  	Polygonlist = Triangulate.ConvexPartition(polygontextureVertices, TriangulationAlgorithm.Bayazit);
  	PolygonScale = 1f;
  	Vector2 polygonvertScale = new Vector2(ConvertUnits.ToSimUnits(1)) * PolygonScale;
  	foreach (Vertices polygonvertices in Polygonlist)
  	{
  		polygonvertices.Scale(ref polygonvertScale);
  	}

I don’t understand why it is working now, but the most important thing is that it works.

Game1.cs

public class Game1 : Game
{
GraphicsDevice graphicsdevice;
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;

  public Body Polygon;
  public float PolygonScale;
  public Vector2 PolygonOrigin;
  public List<Vertices> Polygonlist = new List<Vertices>();
  public Texture2D PolygonSprite;

  public Camera camera;
  public Vector2 vp, gameWorldSize = new Vector2(1334, 750);
  public float ScaleX, ScaleY, Scale;
  Vector2 Newcameraposition;

  public bool Draw_debugView = false;
  public DebugViewXNA physicsDebug;
  public World world;
  public Body Ball;
  public Texture2D BallSprite;
  public bool UpdateFarseerWorld = false;

  public Texture2D Menubackground, Introbackground, Settingsbackground;
  public float delta;
  public bool NextGameState = false, Settingscreenactivated = false;
  IState lastState, currentState, savelastState;

  public ContentManager SettingsContent;
  public ContentManager IntroContent;
  public ContentManager MenuContent;

  public enum GameStates
  {
  	IntroState = 0,
  	MenuState = 1,
  	SettingsState = 2
  }

  public void ChangeGameState(GameStates newState)
  {
  	if (newState == currentGameState)
  		return;
  	lastGameState = currentGameState;
  	lastState = currentState;
  	switch (newState)
  	{
  		case GameStates.IntroState:
  			currentState = new Intro(this, GraphicsDevice);
  			currentGameState = GameStates.IntroState;
  			break;
  		case GameStates.MenuState:
  			currentState = new Menu(this, GraphicsDevice);
  			currentGameState = GameStates.MenuState;
  			if (IntroContent != null)
  				IntroContent.Unload();	
  			if (SettingsContent != null)
  				SettingsContent.Unload();
  			break;								
  		case GameStates.SettingsState:
  			currentState = new Settings(this, GraphicsDevice);
  			currentGameState = GameStates.SettingsState;
  			break;

  	}
  	currentState.Load(Content);
  }

  public void ChangeToLastandCurrent()
  {
  	savelastGameState = currentGameState;
  	currentGameState = lastGameState;
  	lastGameState = savelastGameState;
  	savelastState = currentState;
  	currentState = lastState;
  	lastState = savelastState;
  }

  public GameStates CurrentState
  {
  	get { return currentGameState; }
  	set { currentGameState = value; }
  }

  public GameStates LastState
  {
  	get { return lastGameState; }
  	set { lastGameState = value; }
  }

  private GameStates currentGameState;
  private GameStates lastGameState;
  private GameStates savelastGameState;

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

  protected override void Initialize()
  {
  	currentState = new Intro(this, graphicsdevice);
  	currentGameState = GameStates.IntroState;

  	base.Initialize();
  }

  protected override void UnloadContent()
  {
  	Content.Unload();
  }

  public void IntroLoad()
  {
  	Introbackground = IntroContent.Load<Texture2D>("Content/Introbackground");
  }

  public void SettingsLoad()
  {
  	Settingsbackground = SettingsContent.Load<Texture2D>("Content/Settingsbackground");		

  	if (world == null)
  	{
  		world = new World(new Vector2(0, 7));
  	}
  	else
  	{
  		world.Clear();
  		world = new World(new Vector2(0, 7));
  	}
  	UpdateFarseerWorld = true;

  	physicsDebug = new DebugViewXNA(world);
  	physicsDebug.DefaultShapeColor = Color.White;
  	physicsDebug.SleepingShapeColor = Color.LightGray;
  	physicsDebug.LoadContent(GraphicsDevice, Content);

  	Draw_debugView = true;

  	BallSprite = SettingsContent.Load<Texture2D>("Content/Ball");

  	Ball = BodyFactory.CreateCircle(world, 0.25f, 1.0f);
  	Ball.BodyType = BodyType.Dynamic;
  	Ball.Position = new Vector2(6.4f, 3f);
  	Ball.IsSensor = false;
  	Ball.Restitution = 0.4f;
  	Ball.CollisionCategories = Category.Cat30;

  	Polygon = BodyFactory.CreateCompoundPolygon(world, Polygonlist, 1.0f, BodyType.Dynamic);
  	Polygon.BodyType = BodyType.Static;
  	Polygon.IsSensor = false;
  	Polygon.Position = new Vector2(6f, 4.5f);
  	Polygon.Rotation = 0f;
  	Polygon.Restitution = 0.05f;
  	Polygon.CollisionCategories = Category.Cat25;
  }

  public void MenuLoad()
  {
  	Menubackground = MenuContent.Load<Texture2D>("Content/Menubackground");
  }

  protected override void LoadContent()
  {
  	spriteBatch = new SpriteBatch(GraphicsDevice);

  	PolygonSprite = Content.Load<Texture2D>("Ground");

  	uint[] polygondata = new uint[PolygonSprite.Width * PolygonSprite.Height];
  	PolygonSprite.GetData(polygondata);
  	Vertices polygontextureVertices = PolygonTools.CreatePolygon(polygondata, PolygonSprite.Width, false);
  	Vector2 polygoncentroid = -polygontextureVertices.GetCentroid();
  	polygontextureVertices.Translate(ref polygoncentroid);
  	PolygonOrigin = -polygoncentroid;
  	polygontextureVertices = SimplifyTools.ReduceByDistance(polygontextureVertices, 4f);
  	Polygonlist = Triangulate.ConvexPartition(polygontextureVertices, TriangulationAlgorithm.Bayazit);
  	PolygonScale = 1f;
  	Vector2 polygonvertScale = new Vector2(ConvertUnits.ToSimUnits(1)) * PolygonScale;
  	foreach (Vertices polygonvertices in Polygonlist)
  	{
  		polygonvertices.Scale(ref polygonvertScale);
  	}

  	vp = new Vector2(GraphicsDevice.Viewport.Width, GraphicsDevice.Viewport.Height);
  	ScaleX = vp.X / gameWorldSize.X;
  	ScaleY = vp.Y / gameWorldSize.Y;
  	Scale = Math.Min(ScaleX, ScaleY);

  	camera = new Camera(new Vector2(gameWorldSize.X / 2, gameWorldSize.Y / 2), Scale, vp);

  	currentState.Load(Content);

  	TouchPanel.EnabledGestures = GestureType.Tap;
  }

  protected override void Update(GameTime gameTime)
  {
  	delta = (float)gameTime.ElapsedGameTime.TotalSeconds;

  	if ((UpdateFarseerWorld == true) && (world != null))
  		world.Step(Math.Min(delta, (1f / 60f)));

  	Newcameraposition = new Vector2(gameWorldSize.X / 2, gameWorldSize.Y / 2);
  	
  	camera.Update(gameTime, Newcameraposition, Scale, vp);

  	while (TouchPanel.IsGestureAvailable)
  	{
  		GestureSample gs = TouchPanel.ReadGesture();
  		switch (gs.GestureType)
  		{
  			case GestureType.Tap:						
  				NextGameState = true;
  			break;
  		}
  	}

  	if ((lastGameState == GameStates.MenuState) && (currentGameState == GameStates.SettingsState))
  	{
  		lastState.Update(gameTime);
  	}

  	currentState.Update(gameTime);

  	base.Update(gameTime);
  }

  protected override void Draw(GameTime gameTime)
  {
  	graphics.GraphicsDevice.Clear(Color.CornflowerBlue);

  	spriteBatch.Begin(SpriteSortMode.BackToFront, BlendState.AlphaBlend, null, null, null, null, camera.GetMatrix());
    	  if ((lastGameState == GameStates.MenuState) && (currentGameState == GameStates.SettingsState))
  	  {
  		lastState.Render(spriteBatch);
  	  }

  	  currentState.Render(spriteBatch);
  	spriteBatch.End();

  	if (Draw_debugView == true)
  	{
  		float zoom = Scale;
  		float width = (1f / zoom) * ConvertUnits.ToSimUnits(GraphicsDevice.Viewport.Width);
  		float height = (-1f / zoom) * ConvertUnits.ToSimUnits(GraphicsDevice.Viewport.Height);
  		float zNearPlane = 0f;
  		float zFarPlane = 1000000f;
  		Matrix projection = Matrix.CreateOrthographic(width, height, zNearPlane, zFarPlane);

  		float xTranslation = -1 * ConvertUnits.ToSimUnits(camera.PlayerPosition.X);
  		float yTranslation = -1 * ConvertUnits.ToSimUnits(camera.PlayerPosition.Y);
  		Vector3 translationVector = new Vector3(xTranslation, yTranslation, 0f);
  		Matrix view = Matrix.Identity;
  		view.Translation = translationVector;

  			physicsDebug.RenderDebugData(ref projection, ref view);
  	}

  	base.Draw(gameTime);
  }

}

And I draw the Farseer bodies in the settings class.
Settings.cs

public void Render(SpriteBatch batch)
{
batch.Draw(game1.Settingsbackground, new Rectangle((int)game1.gameWorldSize.X / 2, (int)game1.gameWorldSize.Y / 2, game1.Settingsbackground.Width, game1.Settingsbackground.Height), null, Color.White, 0, new Vector2(game1.Settingsbackground.Width / 2, game1.Settingsbackground.Height / 2), SpriteEffects.None, 0.09f);

  	batch.Draw(game1.PolygonSprite, ConvertUnits.ToDisplayUnits(game1.Polygon.Position),
  	           null, Color.White, game1.Polygon.Rotation, game1.PolygonOrigin, game1.PolygonScale, SpriteEffects.None,
  									  0.05f);
  	
  	batch.Draw(game1.BallSprite, ConvertUnits.ToDisplayUnits(game1.Ball.Position),														null,
  	           Color.White, game1.Ball.Rotation, new Vector2(game1.BallSprite.Width / 2.0f, game1.BallSprite.Height / 2.0f), 1f,
  												SpriteEffects.None, 0.04f);
  }