Time for action – updating and drawing Asteroids

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

   Public Sub Update(gameTime As GameTime)
       For Each asteroid As Sprite In Asteroids
           asteroid.Update(gameTime)
           If Not isOnScreen(asteroid) Then
               asteroid.Location = randomLocation()
               asteroid.Velocity = randomVelocity()
           End If
       Next
   End Sub
   
   Public Sub Draw(spriteBatch As SpriteBatch)
       For Each asteroid As Sprite In Asteroids
           asteroid.Draw(spriteBatch)
       Next
   End Sub

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

   Private _asteroidManager As 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, 0, 50, 50),
       20,
       Me.Window.ClientBounds.Width    Me.Window.ClientBounds.Height)

4. Add the following line to Game1...