XNA 4.0 Game Development by Example Beginner's Guide

Time for action – bouncing asteroids – part 1

1. Add the BounceAsteroids() method to the AsteroidManager class:

   private void BounceAsteroids(Sprite asteroid1, Sprite asteroid2)
   {
       {
           Vector2 cOfMass = (asteroid1.Velocity + 
               asteroid2.Velocity) / 2;
   
           Vector2 normal1 = asteroid2.Center - asteroid1.Center;
           normal1.Normalize();
           Vector2 normal2 = asteroid1.Center - asteroid2.Center;
           normal2.Normalize();
   
           asteroid1.Velocity -= cOfMass;
           asteroid1.Velocity = 
               Vector2.Reflect(asteroid1.Velocity, normal1);
           asteroid1.Velocity += cOfMass;
   
           asteroid2.Velocity -= cOfMass;
           asteroid2.Velocity = 
               Vector2.Reflect(asteroid2.Velocity, normal2);
   
           asteroid2.Velocity += cOfMass;
       }
   }

What just happened?

We begin by calculating the velocity of the center of mass for the collision, ...