How to Check if an Object is Active in Unity

In Unity, game objects can be enabled or disabled during gameplay. Objects that are enabled are considered "active" while disabled objects are inactive. Checking if an object is currently active in your Unity scenes can be useful for a variety of gameplay programming tasks.

Here are some different ways to check if a game object is active in Unity:

Using activeSelf

The easiest way to check if a game object is active is by accessing its .activeSelf property. This will return true if the object is enabled and false if it is disabled.

For example:

```

public GameObject myObject; 

void Update() 

{

  if(myObject.activeSelf) {

    //object is active

  } else { 

    //object is inactive

  }

}

```

Using ActiveInHierarchy

For objects in the scene hierarchy, you can also use .activeInHierarchy to check if they are active. This takes into account parent object statuses as well.

For example:

```

public GameObject myObject;

void Update() {

  if(myObject.activeInHierarchy) {

    //object is active in hierarchy

  }

} 

```

Comparing Against null

Since disabled objects are essentially destroyed, you can check if an object reference is null to see if it is still active.

For example:

```

public GameObject myObject;

void Update() {

  if(myObject != null) {

    //myObject is active

  } else {

    //myObject is disabled

  }

}

```

Using Object.FindObjectOfType

Object.FindObjectOfType returns the first active object of a specified type. It will return null if no active object of that type exists.

For example:

```

Enemy enemy = Object.FindObjectOfType<Enemy>();

if(enemy != null) {

  //active enemy exists 

} else {

  //no active enemy

}

```

Checking Active from Object Pool

If instantiating objects from an object pool, the .activeSelf property can check if an object in the pool is in use or not.

For example:

```

public GameObject enemyPrefab;

public GameObject[] enemyPool;

void SpawnEnemy() {

  for(int i = 0; i < enemyPool.Length; i++) {

    if(!enemyPool[i].activeSelf) {

      enemyPool[i].SetActive(true);

      return;

    }

  }

  //no inactive enemies, spawn new one

  GameObject enemy = Instantiate(enemyPrefab);

}

```

There are a few different ways to check for active objects in Unity depending on your specific use case. Leveraging the appropriate techniques can help streamline gameplay scripting logic that requires distinguishing between enabled and disabled objects.