"Object Reference not set to an instance of an object" comes up after attacking an object

Hello I am making a defense game based around melee combat. I want the enemy to attack an object, but each time the enemy should actually be hitting the object, the error comes up instead. Here is the code:

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class BruteAttack : MonoBehaviour
5. {
6.     private float distance = 1.0f;
7.     public float timeBetweenAttacks = 0.5f;
8.     public int attackDamage = 10;
9.  
10.  
11.     Animator anim;
12.     GameObject player;
13.     CoreHealth coreHealth;
14.     EnemyHealth enemyHealth;
15.     bool playerInRange;
16.     float timer;
17.     GameObject brute;
18.  
19.     void Awake()
20.     {
21.         player = GameObject.Find("Core");
22.         coreHealth = player.GetComponent<CoreHealth>();
23.         enemyHealth = GetComponent<EnemyHealth>();
24.         anim = GetComponent<Animator>();
25.     }
26.  
27.     void OnCollisionEnter(Collision col)
28.     {
29.         if (col.gameObject.name == "Core")
30.         {
31.             anim.SetTrigger("AttackCore");
32.             InvokeRepeating("Attack", 0, 1.65f);
33.         }
34.     }
35.  
36.     void Attack()
37.     {
38.         Ray ray = new Ray(transform.position, transform.forward);
39.         RaycastHit hit;
40.         if (Physics.Raycast(ray, out hit, distance) && hit.collider.gameObject.tag == "Player" && /*(coreHealth.currentHealth > 0)*/ hit.collider != null)
41.  
42.         {
43.             timer = 0f;
44.  
45.             coreHealth.TakeDamage(attackDamage);
46.                
47.                 Debug.Log("Brute Hit");
48.         }
49.  
50.         if (coreHealth.currentHealth < 1)
51.         {
52.             anim.SetTrigger("CoreDead");
53.         }
54.     }
55. }

 

What's the exact error? You didn't even tell which line the error refers to.

You can also debug the collision when it happens, something like: Debug.Log("Hit: "+col.name);

You are also checking (hit.collider!=null) after you have referenced to hit.collider in other comparison.

 

It is referencing coreHealth.TakeDamage(attackDamage);

The CoreHealth script:

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class CoreHealth : MonoBehaviour
5. {
6.     private Rigidbody rbody;
7.     public int startingHealth = 100;
8.     public GameObject explosion;
9.     public int currentHealth;
10.     //public Slider healthSlider;
11.     //public Image damageImage;
12.     public AudioClip deathClip;
13.     public float flashSpeed = 5f;
14.     public Color flashColour = new Color(1f, 0f, 0f, 0.1f);
15.  
16.  
17.     Animator anim;
18.     AudioSource playerAudio;
19.     bool isDead;
20.     bool damaged;
21.  
22.  
23.  
24.     void Awake()
25.     {
26.         anim = GetComponent<Animator>();
27.         playerAudio = GetComponent<AudioSource>();
28.         currentHealth = startingHealth;
29.  
30.     }
31.  
32.     public void TakeDamage(int amount)
33.     {
34.         damaged = true;
35.  
36.         currentHealth -= amount;
37.  
38.         if (currentHealth <= 0 && !isDead)
39.         {
40.             Death();
41.             playerAudio.Play();
42.             GameObject[] gameObjects = GameObject.FindGameObjectsWithTag("Player");
43.             foreach (GameObject target in gameObjects)
44.             {
45.                 GameObject.Destroy(target);
46.                 Instantiate(explosion, transform.position, transform.rotation);
47.             }
48.         }
49.     }
50.  
51.    
52.     void Death()
53.     {
54.         isDead = true;
55.  
56.         Debug.Log("Dead");
57. }

 

So the problem is coreHealth being null. It could happen when you destroy gameobject. You could add these lines at beginning of Attack() in BruteAttack class:

Code (CSharp):

1. Debug.Log(coreHealth);
2. if (!coreHealth) return;