How to check if a game object is destroyed from array? And instantiate a new game object when a game object is destroyed?

Questions & Answers
1

So I want to be able to know if a game object is destroyed from an array and the array count will be for example is 5, when a game object is destroyed, the count will be then be reduced to four. And if the count is less than 5, I want to be able to instantiate another game object.

This is my code.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class SpawnEnemy : MonoBehaviour {

public GameObject[] go;
public Vector3 spawnPosition;
public int spawnLimit;
public int spawnCount;
public bool spawn;
public float waitTime;
public float timer;

void Start(){

}

void Update(){
	if(spawn){
		timer += Time.deltaTime;
		if (timer > waitTime) {
			if (spawnCount < spawnLimit) {
				Spawn ();
				timer = 0.0f;
			} else {
				spawn = false;
				Debug.Log ("Spawn limit has been reached!");
			}
		}
	}
}

void Spawn(){
	GameObject gos = go [Random.Range(0, go.Length)];
	Instantiate (gos, spawnPosition, Quaternion.Euler (90, 0, 0));
	spawnCount++;
	Debug.Log ("Spawned game object #" + spawnCount);
}

}

2

You could create another script assignable to the spawned object that notifies SpawnEnemy when it’s destroyed (or just handle it inside your enemy AI script when it dies/is destroyed).

Here would be your SpawnEnemy:

using UnityEngine;

public class SpawnEnemy : MonoBehaviour
{
    public GameObject[] go;
    public Vector3 spawnPosition;
    public int spawnLimit;
    public float waitTime;

    bool spawn;
    float timer;
    int spawnCount;

    void Update()
    {
        if (spawn)
        {
            timer += Time.deltaTime;
            if (timer > waitTime)
            {
                if (spawnCount < spawnLimit)
                {
                    Spawn();
                    timer = 0.0f;
                }
                else
                {
                    spawn = false;
                    Debug.Log("Spawn limit has been reached!");
                }
            }
        }
    }

    void Spawn()
    {
        GameObject gos = go[Random.Range(0, go.Length)];
        GameObject spawned = Instantiate(gos, spawnPosition, Quaternion.Euler(90, 0, 0));
        spawnCount++;
        SpawnedObject spawnedObject = spawned.AddComponent<SpawnedObject>();
        spawnedObject.spawner = this;
        Debug.Log("Spawned game object #" + spawnCount);
    }

    public void Despawn()
    {
        spawnCount--;
        spawn = true;
    }
}

and here is a sample script to notify SpawnEnemy:

using UnityEngine;

public class SpawnedObject : MonoBehaviour
{
    public SpawnEnemy spawner;

    void OnDestroy()
    {
        if (spawner != null)
            spawner.Despawn();
    }
}