Hide gameobject until certain condition has been met,Hide an object until a condition is met.

Questions & Answers
1

Hello, I am trying to hide an object “door” until all the enemies have been destroyed. From other questions I saw on here I opted for using renderer, but I keep getting an error message.

thank you ahead of time

MissingComponentException: There is no ‘Renderer’ attached to the “Door_Prefab” game object, but a script is trying to access it.
You probably need to add a Renderer to the game object “Door_Prefab”. Or your script needs to check if the component is attached before using it.
Door.Update () (at Assets/Scripts/Door.cs:31)

void Update()
{
    if(GameObject.FindWithTag("Enemy"))
    {
        gameObject.GetComponent<Renderer>().enabled = false;
    }
      else
    {
        gameObject.GetComponent<Renderer>().enabled = true;
    }
}
2

I think you should create a GameManager, always enabled, responsible for detecting when your enemies are destroyed. Then, your Door script will be warned by the GameManager once all the enemies are destroyed.

// Enemy.cs
using UnityEngine;

public class Enemy : MonoBehaviour, IPointerClickHandler
{
    public event System.Action<Enemy> OnKilled;

    void OnDisable()
    {
        if ( OnKilled != null )
            OnKilled.Invoke( this );
    }
}

// GameManager.cs
using UnityEngine;

public class GameManager : MonoBehaviour
{
    private int remainingEnemies = 0 ;
    public event System.Action OnLastEnemyKilled;

    private void Start()
    {
        Enemy[] enemies = FindObjectsOfType<Enemy>();
        for ( int i = 0 ; i < enemies.Length ; i++ )
        {
            AddEnemy( enemies *) ;*

}
}

private void AddEnemy( Enemy enemy )
{
remainingEnemies++ ;
enemy.OnKilled += RemoveEnemy ;
}

private void RemoveEnemy( Enemy enemy )
{
enemy.OnKilled -= RemoveEnemy ;
remainingEnemies-- ;
if( remainingEnemies == 0 && OnLastEnemyKilled != null )
OnLastEnemyKilled.Invoke() ;
}
}
// Door.cs
using UnityEngine;

public class Door: MonoBehaviour
{
// Drag & drop the object in the inspector
public GameManager GameManager ;

private void Awake()
{
GameManager.OnLastEnemyKilled += Show ;
Hide();
}

private void Show()
{
GameManager.OnLastEnemyKilled -= Show ;
gameObject.SetActive( true ) ;
}

private void Hide()
{
gameObject.SetActive( false ) ;
}
}
----
###ORIGINAL ANSWER
Simply disable the gameobject instead of disabling the Renderer component:
gameObject.SetActive( GameObject.FindWithTag(“Enemy”) == null ) ;
However, keep in mind that calling the FindXXX functions are not very efficient. If you have only few calls in your scene, it’s fine.

3

If you don’t want to disable the gameObject as @Hellium suggests, you need to enable & disable the MeshRenderer component.

gameObject.GetComponent<MeshRenderer>().enabled = true;

By the way: the GetComponent function is called every frame in the Update function. It’s terrible for performance. You should store the MeshRenderer in a variable.