Silverlight Pixel Perfect Collsion Detection - silverlight

Question

I am working on a project for my Uni, and I am currently stuck on a Pixel Perfect Collision Detection from this website http://www.andybeaulieu.com/Home/tabid/67/EntryID/160/Default.aspx. I have downloded example project that is using this collsion detection and it is working fine even with my own pictures. I have done the same thing in my project and it is not working. Here is the link to my app: https://www.cubby.com/pl/LostInTheMath.zip/_dd23e2c827604c068a3fe63ff42d22b2 could anyone tell me whats wrong with it? Thank you.
Here is the main code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Windows.Media.Imaging;
namespace LostInTheMath
{
public partial class MainPage : UserControl
{
public MainPage()
{
InitializeComponent();
this.Loaded += new RoutedEventHandler(Page_Loaded);
}
void Page_Loaded(object sender, RoutedEventArgs e)
{
CompositionTarget.Rendering += new EventHandler(CompositionTarget_Rendering);
}
private void UserCntrl_MouseMove(object sender, MouseEventArgs e)
{
Point pt = e.GetPosition(cnvHitTest);
Monkey.SetValue(Canvas.LeftProperty, pt.X);
Monkey.SetValue(Canvas.TopProperty, pt.Y);
}
void CompositionTarget_Rendering(object sender, EventArgs e)
{
Image MonkeyShell = Monkey.FindName("imgMonkey") as Image;
Image Mazer = Maze.FindName("imgMaze") as Image;
if (CheckCollision(Monkey, MonkeyShell, Maze, Mazer))
{
Monkey.Width = 1000;
txtStatus.Text = "Collision with XAML Element!";
return;
}
txtStatus.Text = string.Empty;
}
private bool CheckCollision(FrameworkElement control1, FrameworkElement controlElem1, FrameworkElement control2, FrameworkElement controlElem2)
{
// first see if sprite rectangles collide
Rect rect1 = UserControlBounds(control1);
Rect rect2 = UserControlBounds(control2);
rect1.Intersect(rect2);
if (rect1 == Rect.Empty)
{
// no collision - GET OUT!
return false;
}
else
{
bool bCollision = false;
Point ptCheck = new Point();
// NOTE that creating the writeablebitmap is a bit intense
// so we will do this once and store results in Tag property
// in a real game, you might abstract this into a Sprite class.
if (controlElem1 is Image)
controlElem1.Tag = GetWriteableBitmap(control1);
if (controlElem2 is Image)
controlElem2.Tag = GetWriteableBitmap(control2);
// now we do a more accurate pixel hit test
for (int x = Convert.ToInt32(rect1.X); x < Convert.ToInt32(rect1.X + rect1.Width); x++)
{
for (int y = Convert.ToInt32(rect1.Y); y < Convert.ToInt32(rect1.Y + rect1.Height); y++)
{
ptCheck.X = x;
ptCheck.Y = y;
if (CheckCollisionPoint(ptCheck, control1, controlElem1))
if (CheckCollisionPoint(ptCheck, control2, controlElem2))
{
bCollision = true;
break;
}
}
if (bCollision) break;
}
return bCollision;
}
}
public bool CheckCollisionPoint(Point pt, FrameworkElement control, FrameworkElement controlElem)
{
if (controlElem is Image)
{
// NOTE that we saved the WB in the Tag object for performance.
// in a real app, you might abstract this in your sprite class.
WriteableBitmap wb = controlElem.Tag as WriteableBitmap;
int width = wb.PixelWidth;
int height = wb.PixelHeight;
double offSetX = Convert.ToDouble(control.GetValue(Canvas.LeftProperty));
double offSetY = Convert.ToDouble(control.GetValue(Canvas.TopProperty));
pt.X = pt.X - offSetX;
pt.Y = pt.Y - offSetY;
int offset = Convert.ToInt32((width * pt.Y) + pt.X);
return (wb.Pixels[offset] != 0);
}
else
{
List<UIElement> hits = System.Windows.Media.VisualTreeHelper.FindElementsInHostCoordinates(pt, controlElem) as List<UIElement>;
return (hits.Contains(controlElem));
}
}
private WriteableBitmap GetWriteableBitmap(FrameworkElement control)
{
WriteableBitmap wb = new WriteableBitmap((int)control.Width, (int)control.Height); ;
wb.Render(control, new TranslateTransform());
wb.Invalidate();
return wb;
}
public Rect UserControlBounds(FrameworkElement control)
{
Point ptTopLeft = new Point(Convert.ToDouble(control.GetValue(Canvas.LeftProperty)), Convert.ToDouble(control.GetValue(Canvas.TopProperty)));
Point ptBottomRight = new Point(Convert.ToDouble(control.GetValue(Canvas.LeftProperty)) + control.Width, Convert.ToDouble(control.GetValue(Canvas.TopProperty)) + control.Height);
return new Rect(ptTopLeft, ptBottomRight);
}
}
}