Time for action – constructing the Particle class

1. Add a new class called Particle.cs to the Asteroid Belt Assault project.

2. Insert the standard using directives at the top of the class:

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

3. Modify the declaration of the class by adding : Sprite to the end:

   class Particle : Sprite

4. Add declarations to represent the additional members of the Particle class (beyond those of the Sprite class):

   private Vector2 acceleration;
   private float maxSpeed;
   private int initialDuration;
   private int remainingDuration;
   private Color initialColor;
   private Color finalColor;

5. Add properties to access the information about the underlying members:

   public int ElapsedDuration
   {
       get
       {
           return initialDuration - remainingDuration;
       }
   }
   
   public float DurationProgress
   {
       get
       {
           return (float)ElapsedDuration/
               (float)initialDuration;
       }
   }
   
   public bool IsActive
   {
       get
       {
           return (remainingDuration > 0)...