How do I detect a collision with my map? I want to detect a collision with my map and my car. scanning for the colors.

on my undermap: the track is gray, the grass is white and the walls are yellow.

on my uppermap: the track is more realistic, it is what they see.

I tried <http://www.xnadevelopment.com/tutorials/theroadnottaken/theroadnottaken.shtml> but when I was at collisions, the code won't work. A lot of that is not working in XNA 4.0 but it is exactly what I could use. 

```
//This method checks to see if the Sprite is going to move into an area that does
//not contain all Gray pixels. If the move amount would cause a movement into a non-gray
//pixel, then a collision has occurred.
private bool CollisionOccurred(int aMove)
{

    //Calculate the Position of the Car and create the collision Texture. This texture will contain
    //all of the pixels that are directly underneath the sprite currently on the Track image.
    float aXPosition = (float)(-mCarWidth / 2 + mCarPosition.X + aMove * Math.Cos(mCarRotation));
    float aYPosition = (float)(-mCarHeight / 2 + mCarPosition.Y + aMove * Math.Sin(mCarRotation));
    Texture2D aCollisionCheck = CreateCollisionTexture(aXPosition, aYPosition);

    //Use GetData to fill in an array with all of the Colors of the Pixels in the area of the Collision Texture
    int aPixels = mCarWidth * mCarHeight;
    Color[] myColors = new Color[aPixels];
    aCollisionCheck.GetData<Color>(0, new Rectangle((int)(aCollisionCheck.Width / 2 - mCarWidth / 2), (int)(aCollisionCheck.Height / 2 - mCarHeight / 2), mCarWidth, mCarHeight), myColors, 0, aPixels);

    //Cycle through all of the colors in the Array and see if any of them
    //are not Gray. If one of them isn't Gray, then the Car is heading off the road
    //and a Collision has occurred
    bool aCollision = false;
    foreach (Color aColor in myColors)
    {
        //If one of the pixels in that area is not Gray, then the sprite is moving
        //off the allowed movement area
        if (aColor != Color.Gray)
        {
            aCollision = true;
            break;
        }
    }
    return aCollision;
}

```

Part 2

```
//Create the Collision Texture that contains the rotated Track image for determing
//the pixels beneath the Car srite.
private Texture2D CreateCollisionTexture(float theXPosition, float theYPosition)
{
    //Grab a square of the Track image that is around the Car
    graphics.GraphicsDevice.SetRenderTarget(0, mTrackRender);
    graphics.GraphicsDevice.Clear(ClearOptions.Target, Color.Red, 0, 0);

    mSpriteBatch.Begin();
    mSpriteBatch.Draw(mTrack, new Rectangle(0, 0, mCarWidth + 100, mCarHeight + 100), 
        new Rectangle((int)(theXPosition - 50), 
        (int)(theYPosition - 50), mCarWidth + 100, mCarHeight + 100), Color.White);
    mSpriteBatch.End();

    graphics.GraphicsDevice.ResolveRenderTarget(0);
    graphics.GraphicsDevice.SetRenderTarget(0, null);

    Texture2D aPicture = mTrackRender.GetTexture();

    //Rotate the snapshot of the area Around the car sprite and return that 
    graphics.GraphicsDevice.SetRenderTarget(0, mTrackRenderRotated);
    graphics.GraphicsDevice.Clear(ClearOptions.Target, Color.Red, 0, 0);

    mSpriteBatch.Begin();
    mSpriteBatch.Draw(aPicture, new Rectangle((int)(aPicture.Width / 2), (int)(aPicture.Height / 2), 
        aPicture.Width, aPicture.Height), new Rectangle(0, 0, aPicture.Width, aPicture.Width), 
        Color.White, -mCarRotation, new Vector2((int)(aPicture.Width / 2), (int)(aPicture.Height / 2)), SpriteEffects.None, 0);
    mSpriteBatch.End();

    graphics.GraphicsDevice.ResolveRenderTarget(0);
    graphics.GraphicsDevice.SetRenderTarget(0, null);

    return mTrackRenderRotated.GetTexture();
}

```