XNA 4.0 Game Development by Example Beginner's Guide

Time for action – updating and drawing asteroids

1. Add the Update() and Draw() methods to the AsteroidManager class:

   public void Update(GameTime gameTime)
   {
       foreach (Sprite asteroid in Asteroids)
       {
   
           asteroid.Update(gameTime);
           if (!isOnScreen(asteroid))
           {
               asteroid.Location = randomLocation();
               asteroid.Velocity = randomVelocity();
           }
       }
   }
   
   public void Draw(SpriteBatch spriteBatch)
   {
       foreach (Sprite asteroid in Asteroids)
       {
           asteroid.Draw(spriteBatch);
       }
   }

2. Add a declaration for the AsteroidManager in the declarations section of the Game1 class:

   AsteroidManager asteroidManager;

3. In the Game1 class' LoadContent() method, initialize asteroidManager after the initialization of the starField object:

   asteroidManager = new AsteroidManager( 10, spriteSheet, new Rectangle(0, ...