Problem with enemies killed counter to Debug.log

Heya!

Im new to C# scripting and working on first project with Unity & C#. I'm trying to do a counter that adds +1 every time a bullet destroys an enemy. At the moment I can Debug.Log one enemy killed, but it doesn't add up after I kill second enemy. Any ideas how to get this fixed?

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class EnemyBeha : MonoBehaviour
6. {
7.     GameManager _gameManager;
8.     [SerializeField] GameObject _player;
9.  
10.     float _enemyHealth = 100f;
11.     float _enemyMoveSpeed = 2f;
12.     Quaternion _targetRotation;
13.     bool _disableEnemy = false;
14.     Vector2  _moveDirection;
15.     public float _enemiesKilled;
16.  
17.    
18.  
19.     // Start is called before the first frame update
20.     void Start()
21.     {
22.         _gameManager = GameObject.Find("GameManager").GetComponent<GameManager>();
23.         _player = GameObject.FindGameObjectWithTag("Player");
24.        
25.     }
26.  
27.     // Update is called once per frame
28.     void Update()
29.     {
30.         if(!_gameManager._gameOver && !_disableEnemy)
31.         {
32.             MoveEnemy();
33.             RotateEnemy();
34.         }
35.     }
36.  
37.     void MoveEnemy()
38.     {
39.         transform.position = Vector2.MoveTowards(transform.position, _player.transform.position, _enemyMoveSpeed * Time.deltaTime);
40.     }
41.  
42.      void RotateEnemy()
43.     {
44.        _moveDirection = _player.transform.position - transform.position;
45.        _moveDirection.Normalize();
46.  
47.        _targetRotation = Quaternion.LookRotation(Vector3.forward, _moveDirection);
48.  
49.        if(transform.rotation != _targetRotation)
50.        {
51.             transform.rotation = Quaternion.RotateTowards(transform.rotation, _targetRotation, 333 * Time.deltaTime);
52.        }
53.     }
54.  
55.     void OnCollisionEnter2D(Collision2D collision)      //Enemy object collision check
56.     {
57.         if (collision.gameObject.tag == "Bullet")       // With Bullet
58.         {
59.             StartCoroutine(Damaged());                
60.             _enemyHealth -= 40f;                        // If bullet hits, enemyhealth -40 (total 100 at start)
61.                
62.             if (_enemyHealth <= 0f)                     // If health goes below 0
63.             {
64.               _enemiesKilled ++;                        // add +1 to _enemiesKilled
65.               Destroy(gameObject);                      // destroy the Enemy
66.               Debug.Log(_enemiesKilled);                // debug for testing
67.             }
68.  
69.             Destroy(collision.gameObject);
70.  
71.      
72.  
73.         }
74.         else if (collision.gameObject.tag == "Player")
75.         {
76.             _gameManager._gameOver = true;
77.             collision.gameObject.SetActive(false);
78.         }
79.     }
80.  
81.     IEnumerator Damaged()
82.  
83.     {
84.         _disableEnemy = true;
85.         yield return new WaitForSeconds(0.5f);
86.         _disableEnemy = false;
87.  
88.     }
89. }
90.  

 

The problem is that a different instance of EnemyBeha exists for every enemy and your counter variable is a "member" variable. It's tied to the instance.

Quick and dirty solution:
Make the variable static. Then it is a class variable. However make sure to have it set to zero somewhere at game or scene start (in a global controller, not in the start of the EnemyBeha) because static variable retain their value throughout the whole game session (not editor session).

Better variant:
Use some manager object which is unique and which you access via "Singleton Pattern".

 

There's also a variant where you use ScriptableObjects, which in my opinion would be pretty nice for this situation.

 

Hmm, that requires to assign the SOs to a serialized variable on the EnemyBeha.
Personally I rather use SOs when requiring data that is not completely generated at playtime (like this debug variable is).

 

Oh yeah I see. Did not understand why did the counter reset. But ur message clarified me that. So when the script destroys the object it also destroyes the counter since its attached to the object.

Thank for helping Newbie!