Detecting collisions

We don't need to detect everything bumping into everything else. Specifically we need to detect the following three cases:

• An alien bumping into the player- resulting in losing a life
• The alien laser bumping into the player resulting in losing a life
• The player's laser bumping into an alien resulting in the score going up, a particle effect explosion and the dead alien being respawned.

In the update method of the PhysicsEngine class change the return statement as highlighted next

// This signature and much more will change later in the project
boolean update(long fps, ArrayList<GameObject> objects,
                  GameState gs, SoundEngine se,
                  ParticleSystem ps){

   // Update all the game objects
   for (GameObject object : objects) {
         if (object.checkActive()) {
               object.update(fps, objects
                     .get(Level.PLAYER_INDEX).getTransform());
         }
   }

   if(ps.mIsRunning){
      ps.update(fps);...