unity游戏教程 space shooter （销毁）

为了更好地理解unity，模仿了教程，以下均为教程中的代码：

DestroyByBoundary：

using UnityEngine;
using System.Collections;

public class DestroyByBoundary : MonoBehaviour
{
	void OnTriggerExit (Collider other) 
	{
		Destroy(other.gameObject);
	}
}

DestroyByContact.cs:

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

public class DestroyByContact : MonoBehaviour {

	public GameObject explosion;
	public GameObject playerExpolsion;
	public int score;
	private GameController gameController;

	void Start(){
		GameObject gameControllerObject = GameObject.FindWithTag ("GameController");
		if(gameControllerObject != null){
			gameController = gameControllerObject.GetComponent<GameController> ();
		}
		if(gameControllerObject == null){
			Debug.Log("can not find 'GameController'script");
		}
	}



	void OnTriggerEnter(Collider other){

		if(other.tag=="Boundary"){
			return;
		}

		Instantiate (explosion, transform.position, transform.rotation);

		if(other.tag=="Player"){
			Instantiate (playerExpolsion,other.transform.position,other.transform.rotation);
			gameController.GameOver ();
		}

		gameController.addScore (score);
		Destroy (other.gameObject);
		Destroy (gameObject);

	}
}

DestroyByBoundary：

using UnityEngine;
using System.Collections;

public class DestroyByBoundary : MonoBehaviour
{
	void OnTriggerExit (Collider other) 
	{
		Destroy(other.gameObject);
	}
}

DestroyByContact.cs:

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

public class DestroyByContact : MonoBehaviour {

	public GameObject explosion;
	public GameObject playerExpolsion;
	public int score;
	private GameController gameController;

	void Start(){
		GameObject gameControllerObject = GameObject.FindWithTag ("GameController");
		if(gameControllerObject != null){
			gameController = gameControllerObject.GetComponent<GameController> ();
		}
		if(gameControllerObject == null){
			Debug.Log("can not find 'GameController'script");
		}
	}



	void OnTriggerEnter(Collider other){

		if(other.tag=="Boundary"){
			return;
		}

		Instantiate (explosion, transform.position, transform.rotation);

		if(other.tag=="Player"){
			Instantiate (playerExpolsion,other.transform.position,other.transform.rotation);
			gameController.GameOver ();
		}

		gameController.addScore (score);
		Destroy (other.gameObject);
		Destroy (gameObject);

	}
}

DestroyByTime .cs:

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

public class DestroyByTime : MonoBehaviour {

	public float lifeTime;

	// Use this for initialization
	void Start () {
		Destroy (gameObject,lifeTime);
	}
	
	// Update is called once per frame
	void Update () {
		
	}
}