I’m trying to get a goul (player pets) to switch targets when the current target dies.
I can target the first one in the list, but when it dies I get the “transform has been destroyed but you’re still trying to access it” error. As well as not being able to change to the next target in the list.
can someone please look over the code and guide me in the right direction? 
ps, I’m using the tab button for right now, but eventually the target needs to change automatically.
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
public class Goul : MonoBehaviour {
public Enemy2D enemy2D;
public Transform target;
public Transform player;
public int moveSpeed;
private Transform goul;
public int idleDistance = 1;
public int enemyMaxDistance = 20;
public int enemyMinDistance = 2;
//attack vars
public float attackRange = 2;
float attackRate = 1f;
float coolDown = 1;
public int goulDamage = 1;
//targeting vars
public List<Transform> targets;
public Transform selectedTarget;
private Transform myTransform;
//12+ hours on this fucking script...
void Awake(){
goul = transform;
}
void Start () {
targets = new List<Transform> ();
selectedTarget = null;
myTransform = transform;
AddAllEnemies ();
//GameObject to = GameObject.FindGameObjectWithTag ("Enemy");
//target = to.transform;
GameObject po = GameObject.FindGameObjectWithTag("Player");
player = po.transform;
}
public void AddAllEnemies(){
GameObject[] go = GameObject.FindGameObjectsWithTag ("Enemy");
foreach (GameObject enemy in go)
AddTarget (enemy.transform);
}
public void AddTarget(Transform enemy){
targets.Add (enemy);
}
private void SortTargetsByDistance(){
if (selectedTarget != null) {
targets.Sort (delegate(Transform t1, Transform t2) {
return Vector3.Distance (t1.position, myTransform.position).CompareTo (Vector3.Distance (t2.position, myTransform.position));
});
}
}
private void TargetEnemy(){
if (selectedTarget == null) {
SortTargetsByDistance ();
selectedTarget = targets [0];
} else {
int index =targets.IndexOf(selectedTarget);
if(index < targets.Count -1){
index++;
}
else {
index = 0;
}
DeselectTarget();
selectedTarget = targets[index];
}
SelectTarget();
target = selectedTarget.gameObject.transform;
}
//indicates which target you have selected ( next 2)
private void SelectTarget(){
if (selectedTarget != null) {
selectedTarget.renderer.material.color = Color.green;
}
}
public void DeselectTarget(){
selectedTarget.renderer.material.color = Color.red;
selectedTarget = null;
}
void Update (){
Vector3 theScale = transform.localScale;
theScale.x *= -1;
transform.localScale = theScale;
if (Input.GetKeyDown (KeyCode.Tab)) {
TargetEnemy();
}
}
void FixedUpdate () {
if( target != null){
if (Vector3.Distance (goul.position, target.position) < attackRange) {
if (Time.time >= coolDown){
GoulAttack();
coolDown = Time.time + attackRate;
}
}
}
if (target == null || Vector3.Distance (goul.position, target.position) > enemyMaxDistance){
if (Vector3.Distance (goul.position, player.position) > idleDistance) {
if (player.position.x < goul.position.x) {
goul.position -= goul.right * moveSpeed * Time.deltaTime; // player is left of goul, move left
} else if (player.position.x > goul.position.x) {
goul.position += goul.right * moveSpeed * Time.deltaTime; // player is right of goul, move right
}
}
}
else if (target != null) {
if (Vector3.Distance (player.position, target.position) < enemyMaxDistance) {
if (Vector3.Distance (goul.position, target.position) > enemyMinDistance) {
if (target.position.x < goul.position.x) {
goul.position -= goul.right * moveSpeed * Time.deltaTime; // target is left of goul, move left
} else if (target.position.x > goul.position.x) {
goul.position += goul.right * moveSpeed * Time.deltaTime; // target is right of goul, move right
}
}
}
}
Debug.DrawLine(player.position, goul.position, Color.yellow);
if (target != null) {
Debug.DrawLine (target.position, goul.position, Color.green);
}
}
private void GoulAttack(){
//find target with tag
if (target.gameObject.tag == "Enemy") {
//send damage call to enemy script
target.gameObject.SendMessage ("EnemyDamaged", goulDamage, SendMessageOptions.DontRequireReceiver);
}
}
}
