Modifying variable from another script (error)

Question

Hi everyone!

I'm building a simple game in C# - a player shoots a projectile and if it hits the target, the player advances to the next level and if he misses the target he looses 1 (out of 3) lives. After he looses a life, the scene is reloaded but he only has 2 lives left etc. When the player runs out of lives, it's game over.

So far I've got:

PlayerScript

 // Shoot variables
 public int lives = 3;

     void Update ()
         {
             if (lives > 0) {
                     //Shoot 
             }
           //else gameover
         }
          
         public void Shoot()
         {
             ...
         }

ProjectileScript

 public PlayerScript lives; 
     
     void Start () {
         lives = gameObject.GetComponent<PlayerScript> ();
     }
             
     void Update () {
     
     }
 
     void OnCollisionEnter2D (Collision2D coll) {
         if (coll.collider.tag == "target") {
              // next level
             }
         else 
         { 
             lives -= 1;
                     //reload scene* 
         } 
     }

Currently I get the following error:

Operator -= cannot be applied to operands of type PlayerScript and `int'

I have no idea how to fix this. *Also any ideas how could I reload scene (set the objects to the same position as in the beginning with the only difference being -1 life)?

Answer 1

Answer by InvincibleCat · Jan 23, 2015 at 08:33 PM

it is lives.lives -= 1;

But you should also rename PlayerScript lives to PlayerScript player

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mnov · Jan 25, 2015 at 11:45 AM 0

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Now I get the following message:

The name `lives' does not exist in the current context

I also tried a different approach with the following code for ProjectileScript:

 void Start () {
 
     }
     
  
     void Update () {
     
     }
 
     void OnCollisionEnter2D (Collision2D coll) {
         if (coll.collider.tag == "target") {
                   // next level 
             } 
         else 
         { 
             PlayerScript playerScript = GetComponent<PlayerScript>(); 
             playerScript.lives -= 1;
         } 
           
     }

It still doesn't work, the only difference is that now I get

NullReferenceException: Object reference not set to an instance of an object ProjectileScript.OnCollisionEnter2D (UnityEngine.Collision2D coll) (at Assets/Scripts/ProjectileScript.cs:26).

The 26th line of code is playerScript.lives -= 1;

InvincibleCat · Jan 27, 2015 at 06:45 PM 0

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Show me your PlayerScript. Do you understand what the error is telling you?

InvincibleCat · Feb 04, 2015 at 11:50 PM 0

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@mnov can you mark as answer plz ? Or say something ?

InvincibleCat · Feb 13, 2015 at 11:22 PM 0

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@mnov can you mark as answer plz ? Or say something ?

Modifying variable from another script (error)

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