Space Shooter Tutorial adding score

Getting Started
1

Hi guys,
I’ve been running through a series of bugs with this Tutorial on Unity most particularly on the part where you need to a add score. the problem is when I play the game I’m getting an error:
“NullReferenceException: Object reference not set to an instance of an object
DestroyByContact.OnTriggerEnter (UnityEngine.Collider other) (at Assets/Scripts/DestroyByContact.cs:42)”.

After that even I shoot the asteroids they only play the sound and the effect but not disappearing or even adding a score also with the spaceship.

Here’s the code for “Destroy By Contact”:

using UnityEngine;
using System.Collections;

public class DestroyByContact : MonoBehaviour {

public GameObject explotion;
private GameObject newProjectile;
public GameObject playerExplotion;
public int scoreValue;
private GameController gameController;

void start ()
{
/GameObject gameControllerObject = GameObject.FindWithTag(“GameController”);
if (gameController != null)
{
gameController = gameControllerObject.GetComponent();
}
if (gameController == null)
{
Debug.Log(“Cannot Find ‘GameController’ script”);
}/
gameController = GameObject.FindObjectOfType();
if(gameController == null){
Debug.Log(“Cannot Find ‘GameController’ script”);
}
}

void OnTriggerEnter(Collider other)
{
if (other.tag == “Boundary”)
{
return;
}
newProjectile = Instantiate (explotion, transform.position, transform.rotation) as GameObject;
if (other.tag == “Player”)
{
newProjectile = Instantiate (playerExplotion, other.transform.position, other.transform.rotation) as GameObject;

}
gameController.AddScore (scoreValue);
Destroy (other.gameObject);
Destroy (gameObject);

}
}

Here’s the code for “Game Controller”:

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class GameController : MonoBehaviour {

public GameObject hazard;
public Vector3 SpawnValue;
public int hazardCount;
public float spawnWait;
public float startWait;
public float waveWait;

public GUIText scoreText;
private int score;

void Start ()
{
score = 0;
UpdateScore ();
StartCoroutine (SpawnWaves ());
}

IEnumerator SpawnWaves ()
{
yield return new WaitForSeconds (startWait);
while (true)
{
for (int i = 0; i < hazardCount; i++)
{
Vector3 spawnPosition = new Vector3 (Random.Range (-SpawnValue.x, SpawnValue.x), 0.0f, SpawnValue.z);
Quaternion spawnRotation = Quaternion.identity;
Instantiate (hazard, spawnPosition, spawnRotation);
yield return new WaitForSeconds (spawnWait);
}
yield return new WaitForSeconds(waveWait);
}
}

public void AddScore (int newScoreValue)
{
score += newScoreValue;
UpdateScore ();
}

void UpdateScore ()
{
scoreText.text = "Score: " + score;
}

}

Will do appreciate your help as I’m only a beginner in Unity.

2

Look here for how to post code properly on the forums: Using code tags properly

As for your issue, try changing ‘start’ to ‘Start’ in the first script. The method names are case sensitive.

Since it’s difficult to tell which line is which, the way you’ve posted your code so far, if that doesn’t solve your problem, please edit your post with code tags and indicate which line # the error is on, if it doesn’t match up to the pasted code. :slight_smile:

Welcome to Unity!

1 Like
3

Thanks for the help I actually figured it out, all I just need is to make a new function for the class GameController.

void gameController_Main()
{
GameController gameController = new GameController();
gameController = GameObject.FindObjectOfType<GameController>();
GameObject gameControllerObject = GameObject.FindWithTag("GameController");
if (gameController != null)
{
gameController = gameControllerObject.GetComponent<GameController>();
}
if (gameController == null)
{
Debug.Log("Cannot Find 'GameController' script");
}
gameController.AddScore(scorePoints);

}

and declare it on void “OnTriggerEnter(Collider other)” like this:

void OnTriggerEnter(Collider other)
{
if (other.tag == "Boundary")
{
return;
}
newProjectile = Instantiate (explotion, transform.position, transform.rotation) as GameObject;
if (other.tag == "Player")
{
newProjectile = Instantiate(playerExplotion, other.transform.position, other.transform.rotation) as GameObject;

}
gameController_Main();
Destroy(other.gameObject);
Destroy(gameObject);

}

by the way thanks for informing me on how to properly post on a forum.

4

Did you try changing ‘start’ to ‘Start’ ? :slight_smile: Glad it’s working, either way, but ya.