Time for action – updating and drawing the StarField

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

   public void Update(GameTime gameTime)
   {
       foreach (Sprite star in stars)
       {
           star.Update(gameTime);
           if (star.Location.Y > screenHeight)
           {
               star.Location = new Vector2(
                   rand.Next(0, screenWidth), 0);
           }
       }
   }
   
   public void Draw(SpriteBatch spriteBatch)
   {
       foreach (Sprite star in stars)
       {
           star.Draw(spriteBatch);
       }
   }

What just happened?

When the star field needs to be updated, a foreach loop processes each item in the stars list, running the sprite's Update() method. The method then checks the star's Location property's Y component to determine if the star has moved off the bottom of the screen. If it has, the star is assigned a new Location with a random X component and a Y component of zero, placing the star at a random location along the top of the screen.

The StarField.Draw() method simply passes...