Projectiles that don't project

I apologize if this is a repeat of something that came before; I looked, but couldn't find anything related to this particular issue.
The portion of the script at issue is supposed to move a launched projectile to the intended target:

Code (CSharp):

1. IEnumerator OpenFire(Projectile projectile)
2. {
3.     while (GetTargetDistance(targetEnemy) > 0.2f)
4.         {
5.         var dir = targetEnemy.transform.localPosition - transform.localPosition;
6.         var angleDir = Mathf.Atan2(dir.y, dir.x) * Mathf.Rad2Deg;
7.         projectile.transform.rotation = Quaternion.AngleAxis(angleDir, Vector3.forward);
8.         projectile.transform.localPosition = Vector2.MoveTowards(projectile.transform.localPosition, targetEnemy.transform.localPosition, 5f * Time.deltaTime);
9.         yield return null;
10.     }
11.     if (projectile != null || targetEnemy == null)
12.     {
13.         Destroy(projectile);
14.     }
15. }

Everything works getting into the while loop, but the projectiles don't move, and the console error "NullReferenceException: Object reference not set to an instance of an object" links back to the "var dir = targetEnemy....." line. Any thoughts?

 

targetEnemy is probably null. GetTargetDistance probably deals with targetEnemy being null gracefully, but line 5 will generate an error if targetEnemy is null. Add debugging.

 

Seems like you're right, but I still can't find the error. My original post had part of the conditional commented out to expose the error; the whole script is as follows:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class Tower : MonoBehaviour
6. {
7. [SerializeField] private float timeBetweenAttacks;
8. [SerializeField] private float attackRadius;
9. [SerializeField] private Projectile projectile;
10. private Enemy targetEnemy = null;
11. private float attackCounter;
12. private bool isAttacking = false;
13.  
14. void Update()
15. {
16. attackCounter -= Time.deltaTime;
17. if (targetEnemy == null)
18. {
19. Enemy nearestEnemy = GetNearestEnemyInRange();
20. if (nearestEnemy != null && Vector2.Distance(transform.localPosition, nearestEnemy.transform.localPosition) <= attackRadius)
21. {
22. Debug.Log("Enemy in Range!");
23. targetEnemy = nearestEnemy;
24. }
25. }
26. else
27. {
28. if (attackCounter <= 0)
29. {
30. Debug.Log("Ready to Fire!");
31. isAttacking = true;
32. attackCounter = timeBetweenAttacks;
33. }
34. else
35. {
36. isAttacking = false;
37. }
38. if (Vector2.Distance(transform.localPosition, targetEnemy.transform.localPosition) > attackRadius)
39. {
40. targetEnemy = null;
41. }
42. }
43. }
44.  
45. void FixedUpdate()
46. {
47. if (isAttacking)
48. {
49. Debug.Log("Aim!");
50. Attack();
51. }
52. }
53.  
54. public void Attack()
55. {
56. isAttacking = false;
57. Projectile newProjectile = Instantiate(projectile) as Projectile;
58. newProjectile.transform.localPosition = transform.localPosition;
59. if (targetEnemy = null)
60. {
61. Destroy(newProjectile);
62. }
63. else
64. {
65. Debug.Log("Firing!");
66. StartCoroutine(OpenFire(newProjectile));
67. }
68. }
69.  
70. IEnumerator OpenFire(Projectile projectile)
71. {
72. while (GetTargetDistance(targetEnemy) > 0.2f && targetEnemy != null && projectile != null)
73. {
74. var dir = targetEnemy.transform.localPosition - transform.localPosition;
75. var angleDir = Mathf.Atan2(dir.y, dir.x) * Mathf.Rag2Deg;
76. Debug.Log("Target at bearing " + angleDir);
77. Debug.Log("Distance " + dir);
78. projectile.transform.rotation = Quaternion.AngleAxis(angleDir, Vector3.forward);
79. projectile.transform.localPosition = Vector2.MoveTowards(projectile.transform.localPosition, targetEnemy.transform.localPosition, 5f * Time.deltaTime;
80. yield return null;
81. }
82. if (projectile != null || targetEnemy == null)
83. {
84. Destroy(projectile)
85. }
86. }
87.  
88. private float GetTargetDistance(Enemy thisEnemy)
89. {
90. if (thisEnemy == null)
91. {
92. thisEnemy = GetNearestEnemyInRange();
93. if (thisEnemy == null)
94. {
95. return 0f;
96. }
97. }
98. return Mathf.Abs(Vector2.Distance(transform.localPosition, thisEnemy.transform.localPosition));
99. }
100.  
101. private List<Enemy> GetEnemiesInRange()
102. {
103. List<Enemy> enemiesInRange = new List<Enemy>();
104. foreach(Enemy enemy in GameManager.Instance.EnemyList)
105. {
106. if (Vector2.Distance(transform.localPosition, enemy.transform.localPosition) <= attackRadius
107. {
108. enemiesInRange.Add(enemy)
109. }
110. }
111. return enemiesInRange;
112. }
113.  
114. private Enemy GetNearestEnemyInRange()
115. {
116. Enemy nearestEnemy = null;
117. float smallestDistance = float.PositiveInfinity;
118. foreach(Enemy enemy in GetEnemiesInRange())
119. {
120. if (Vector2.Distance(transform.localPosition, enemy.transform.localPosition) < smallestDistance)
121. {
122. smallestDistance = Vector2.Distance(transform.localPosition, enemy.transform.localPosition);
123. nearestEnemy = enemy;
124. }
125. }
126. return nearestEnemy;
127. }
128. }

With the added conditions on the while loop, it never gets triggered which lends heavy weight to targetEnemy being null, but I know it's being assigned because I get the debug message "Enemy in Range!". In fact, all the debug messages up to (and including) "Firing!" all trigger properly

 

Probably line 59 above. A single "=" is for assignment, so that line makes targetEnemy null instead of checking for null.

Code (csharp):

1. if (targetEnemy = null)

 

Found the problem! Line 59 sets to null instead of compares to null

 

Glad you found it

 

Hey buddy, just wanted to say thank you for all your help. Hopefully one day I can return the favour. Cheers!