Learning XNA 3.0

Creating an Automated Sprite

Now that you have a class that allows the user to control a sprite, it's time to add a class that will generate an animated sprite that moves on its own. Add a new class to your project by right-clicking on the project in Solution Explorer and selecting Add → Class. Name the class file AutomatedSprite.cs. Once the file is ready, mark the new class as a subclass of your Sprite class:

class AutomatedSprite: Sprite

Add the same XNA namespaces as before, but without the input namespace because you won't be gathering input from any devices in this class:

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;

Next, add two constructors for the AutomatedSprite class. These constructors will be identical to the ones used for the UserControlledSprite class:

public AutomatedSprite(Texture2D textureImage, Vector2 position, Point frameSize,
    int collisionOffset, Point currentFrame, Point sheetSize, Vector2 speed)
    : base(textureImage, position, frameSize, collisionOffset, currentFrame,
    sheetSize, speed)
{
}

public AutomatedSprite(Texture2D textureImage, Vector2 position, Point frameSize,
    int collisionOffset, Point currentFrame, Point sheetSize, Vector2 speed,
    int millisecondsPerFrame)
    : base(textureImage, position, frameSize, collisionOffset, currentFrame,
    sheetSize, speed, millisecondsPerFrame)
{
}

Your automated sprite will use the speed member of the base class to move around the screen. This will be done through an overridden direction property, because ...