Prefab loses scene variables

Hello. So I created a Bomberman character. I instantiate a prefab bomb from him. Which I can toss to an empty game object that I labeled as the target. However, when the bomb is instantiated it loses the variable for the target because the bomb is a prefab and the target is a child of the player in the scene. I'm having lots of trouble trying to give the bomb a target upon instantiation. Is there any way to give the bomb a target either before it is created of immediately after so it can be thrown right away?




My code to instantiate the bomb

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class BombToss : MonoBehaviour
6. {
7.     public GameObject bomb;
8.     public Transform hands;
9.     public Player player;
10.  
11.     void Update()
12.     {
13.         if (Input.GetButtonDown("Fire1"))
14.         {
15.             Instantiate(bomb, hands.position, Quaternion.Euler(-90, 0, 0));
16.         }
17.  
18.     }
19. }

And my code to calculate the trajectory towards the target.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class Bomb : MonoBehaviour
6. {
7.     public Rigidbody bomb;
8.     public Transform target;
9.  
10.     public float h = 25;
11.     public float gravity = -18;
12.  
13.     private void Start()
14.     {
15.         bomb.useGravity = false;
16.     }
17.  
18.     private void Update()
19.     {
20.         if (Input.GetKeyDown(KeyCode.Space))
21.         {
22.             Launch();
23.         }
24.     }
25.  
26.     void Launch()
27.     {
28.         Physics.gravity = Vector3.up * gravity;
29.         bomb.useGravity = true;
30.         bomb.velocity = CalculateLaunchVelocity();
31.     }
32.  
33.     Vector3 CalculateLaunchVelocity()
34.     {
35.         float displacementY = target.position.y - bomb.position.y;
36.         Vector3 displacementXZ = new Vector3(target.position.x - bomb.position.x, 0, target.position.z - bomb.position.z);
37.  
38.         Vector3 velocityY = Vector3.up * Mathf.Sqrt(-2 * gravity * h);
39.         Vector3 velocityXZ = displacementXZ / (Mathf.Sqrt(-2 * h / gravity) + Mathf.Sqrt((-2 * displacementY) / gravity));
40.  
41.         return velocityXZ + velocityY * -Mathf.Sign(gravity);
42.     }
43. }

 

Yeah, you can't store scene references in a prefab because prefab is not actually in a scene. An instance of a prefab can be in a scene, but the prefab itself Is more like an asset in the project window.

 

So what are you supposed to do instead?

 

You need to populate references to objects in the scene after you have instantated the prefab.

In not-the-actual-code, that would look something like:

Code (csharp):

1.  
2. public Transform bombTarget;
3.  
4. void DropBomb()
5. {
6.     // Make an instance of the Prefabbed object in the Scene
7.     GameObject bombGO = Instantiate(bombPrefab);
8.     bombGO.transform.position = this.transform.position;
9.  
10.     // Do any Scene-specific initialisation required
11.     Bomb bombComponent = bombGO.GetComponent<Bomb>();
12.     bombComponent.target = bombTarget;
13. }