Adding Lives to 2D Shooter tutorial

I'm trying to extend the 2D shooter tutorial by adding number of lives to the GameOver condition.

I've got the GUI text working and incremented but my ship isn't acting correctly.

I extended GameController.cs with a new public variable, livesLeft

Code (CSharp):

1.  
2. public int livesLeft;
3. public GUIText numOfLivesLeft;

Then added a new method called UpdateLives:

Code (CSharp):

1.  void UpdateLives()
2.     {
3.         numOfLives.text = "x " + livesLeft;
4.     }

And set the variables in Start:

Code (CSharp):

1. livesLeft = 3;
2. UpdateLives();

Finally, I modified the Update method, thinking I could just recreate the Player object:

Code (CSharp):

1. void Update()
2.     {
3.  
4.  
5.         if (restart)
6.         {
7.             if (Input.GetKeyDown(KeyCode.R))
8.             {
9.                 Application.LoadLevel(Application.loadedLevel);
10.             }
11.         } else
12.         {
13.             UpdateLives();
14.  
15.             if (livesLeft != 0)
16.             {
17.                 Instantiate(player, player.transform.position, player.transform.rotation);
18.             }
19.         }
20.     }

I then went over to DestroyByContact and intended to update the OnTriggerEnter method like this:

Code (CSharp):

1. if (other.collider.tag == "Player") {
2.  
3.             Instantiate (playerExplosion, other.transform.position, other.transform.rotation);
4.  
5.  
6.             gameController.livesLeft -= 1;
7.             if (gameController.livesLeft == 0)
8.             {
9.                 gameController.GameOver();
10.             }
11.  
12.         }

Except it doesn't work; my livesLeft label gets some crazy value (-227 or some such), and I get the following console exception:

MissingReferenceException: The object of type 'GameObject' has been destroyed but you are still trying to access it.
Your script should either check if it is null or you should not destroy the object.
GameController.Update ()

Can someone point me in the right direction on what I'm doing wrong?

 

I managed to get it working. Now to get the timer on respawn functioning correctly...

 

Hi there, I'm trying to add lives myself and have hit a few hurdles. Do you have a copy of the completed code you added?

Thanks in advance.