OnBecameInvisible with Instantiate objects?

Noob coder. I'm trying to destroy my bullet object once it exists outside the view of the camera. I first tried to create a new void, OnBecameInvisible, and destroy it, but I am finding it difficult to get the void to recognize the GameObject, bullet. Here is my current functioning code.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class PlayerShoot : MonoBehaviour
6. {
7.  
8.     public Transform firePoint;
9.     public GameObject bulletPrefab;
10.     public float bulletForce = 200f;
11.  
12.     // Update is called once per frame
13.     void Update()
14.     {
15.         //delete fluff and use GetbuttonDown to revert
16.          if(Input.GetButtonDown("Fire1"))
17.             {
18.                 Shoot();
19.             }
20.     }
21.  
22.     void Shoot()
23.     {
24.         GameObject bullet = Instantiate(bulletPrefab, firePoint.position, firePoint.rotation);
25.         Rigidbody2D rb = bullet.GetComponent<Rigidbody2D>();
26.         rb.AddForce(firePoint.up * bulletForce, ForceMode2D.Impulse);
27.         Destroy(bullet, 1); //want to change this to destroy once off camera
28.     }
29. }

Is there any way to pass bullet into a 'void OnBecameInvisible'? I tried to add this void below thew void Shoot and couldn't get it to work. This is what I tried versus the code above.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class PlayerShoot : MonoBehaviour
6. {
7.  
8.     public Transform firePoint;
9.     public GameObject bulletPrefab;
10.     public float bulletForce = 200f;
11.     private GameObject bullet;
12.  
13.     // Update is called once per frame
14.     void Update()
15.     {
16.         //delete fluff and use GetbuttonDown to revert
17.          if(Input.GetButtonDown("Fire1"))
18.             {
19.                 Shoot();
20.             }
21.     }
22.  
23.     void Shoot()
24.     {
25.         bullet = Instantiate(bulletPrefab, firePoint.position, firePoint.rotation);
26.         Rigidbody2D rb = bullet.GetComponent<Rigidbody2D>();
27.         rb.AddForce(firePoint.up * bulletForce, ForceMode2D.Impulse);
28.      
29.     }
30.  
31.     void OnBecameInvisible()
32.     {
33.         Destroy(bullet);
34.     }
35. }
36.  

 

Can you just put a timed death sentence on it? You know, something simple like:

Code (csharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class TimedDeathSentence : MonoBehaviour
5. {
6.     public float ageLimit = 2.0f;
7.  
8.     IEnumerator Start()
9.     {
10.         yield return new WaitForSeconds(ageLimit);
11.         Destroy(gameObject);
12.     }
13. }

 

Yeah, that's what I currently have. I'm creating a rail shooter where I don't want the player to be able to begin doing damage to enemies who have not appeared yet.

 

That's totally reasonable.

What about using objects anchored just offscreen as the bounds and checking when you go beyond them? Is it a fixed scrolling shooter kinda deal? If the player is actually moving through space, perhaps parent the bounds to him, or just use raycasts from the camera corners to update them?

It seems for such a simple thing as bounds check I would tend to not reach for an API that might not be as well-documented as one would like...

 

Yeah, you make good points. My player is bound on the y-axis but can freely move on the x-axis, aka left to right. I suppose if I were to do a bound method then the camera bounds would probably be best.

 

I just don't like introducing needless dependencies for something so simple.

I've made a few scrolling shooters in my life too so I feel I can speak.

OTOH I've never even looked on the OnBecameInvisible thing but just hearing it scares me. "What does invisible even mean?" etc.