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As usual, I will discuss the program in fragments, beginning with the Sprite class. Furthermore, I will discuss only those portions of the Sprite class that are different from the versions of the Sprite class that I explained in earlier modules.
A complete listing of the Sprite class is provided in Listing 14 and a complete listing of the Game1 class is provided in Listing 15 near the end of the module.
Scanning down the Sprite class definition in Listing 14 , the first thing that we find that is new to this version is a new read-only Image property accessor method. The method is shown in Listing 1 .
Listing 1 . A new Image property accessor method in the Sprite class.
//Image property accessor - new to this version.
public Texture2D Image {get {
return image;}//end get
}//end Image property accessor There is nothing unusual about this property accessor method, so it shouldn't require further explanation. You will learn why it is needed laterwhen I explain the Game1 class.
The second statement from the end in Listing 2 was added to the constructor from the previous version of the Sprite class.
Listing 2 . A modified constructor.
public Sprite(String assetName,
ContentManager contentManager,Random random) {
image = contentManager.Load<Texture2D>(assetName);
image.Name = assetName;this.random = random;
}//end constructor The new statement assigns the assetName to the Name property of the Texture2D object that represents the sprite's image. You will see why this modification was neededlater.
As with the modified constructor, the last statement in Listing 3 was added to the SetImage method from the previous version of the Sprite class.
Listing 3 . A modified SetImage method.
public void SetImage(String assetName,
ContentManager contentManager) {image = contentManager.Load<Texture2D>(assetName);
image.Name = assetName;}//end SetImage Once again, the new statement assigns the assetName to the Name property of the Texture2D object that represents the sprite's image. You will also see why this modificationwas needed later.
Listing 4 shows a new method named GetRectangle .
Listing 4 . A new method named GetRectangle.
public Rectangle GetRectangle() {
return new Rectangle((int)(position.X),(int)(position.Y),
image.Width,image.Height);
}//end GetRectangle This method returns the current rectangle occupied by the sprite's image as type Rectangle . This rectangle is needed for the collision detection process. The code in Listing 4 is straightforward and shouldn't require further explanation.
This version of the Sprite class defines a new method named IsCollision . The purpose of this new method is to detect a collision between this sprite and some other sprite.
A collision is called if the rectangle containing this Sprite object's image intersects the rectangle containing a target sprite's image.
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