Unity Object not set to an instance

Questions & Answers
1

Hi I get keep this same error and I m not sure why. It keeps happening on my getComponent().
SceneManager sceneManager;

	void OnTriggerEnter(Collider other)
	{
		if (other.gameObject.tag == "asteroid") 
		{
			Vector3 temp = other.transform.position;
			temp.y = 8;
			temp.x = Random.Range(-7.0f,7.0f);
			other.transform.position = temp;
			Destroy(gameObject);

			sceneManager.GetComponent<SceneManager>();
			sceneManager.AddScore();
		}
	}

Here is my SceneManager script

int score = 0;
	
	// Update is called once per frame
	void Update () 
	{
		print ("Your score is: " + score);
	}

	public void AddScore()
	{
	   score += 50;
	}
3

You can use GetComponet() only with game objects not with class or scripts directly . First add an empty game object in your scene and attach your sceneManager script with that empty game object. Then take a reference of that empty object in your OnTriggerEnter script and use GetComponent().

I have the best alternative for you. You can use static function . Replace your

 public void AddScore()
    {
       score += 50;
    }

with

 public static void AddScore()
    {
       score += 50;
    }

and your

    void OnTriggerEnter(Collider other)
    {
       if (other.gameObject.tag == "asteroid") 
       {
         Vector3 temp = other.transform.position;
         temp.y = 8;
         temp.x = Random.Range(-7.0f,7.0f);
         other.transform.position = temp;
         Destroy(gameObject);
 
         sceneManager.GetComponent<SceneManager>();
         sceneManager.AddScore();
       }
    }

with

    void OnTriggerEnter(Collider other)
    {
       if (other.gameObject.tag == "asteroid") 
       {
         Vector3 temp = other.transform.position;
         temp.y = 8;
         temp.x = Random.Range(-7.0f,7.0f);
         other.transform.position = temp;
         Destroy(gameObject);
 
         sceneManager.AddScore();
       }
    }
2

You want to assign sceneManager with GetComponent, thats the false way. You have to attach the sceneManager-Script to any GameObject and call GetComponent on a reference to this gameObject.

You should have a look on the Unity Video Tutorial.