Calculating a leading shoot in C#

Hello Unity community.

I would really appreciate any help anyone could provide me, so if you are reading this let me thank you so much.

Ok, I want to shoot to a mobile target, but not to its current target.transform.position, I need to shoot it to an intercept position between the projectile and the target, so I will hit it if it moves in a constant speed and direction. How should I do that using "Instantiate(bolt,shotSpawn.position,shotSpawn.rotation)"?

We know the distance between the 2 objects every time.
The projectiles have a constant speed and a lifetime of 2 seconds (as maximum).

 

http://wiki.unity3d.com/index.php/Calculating_Lead_For_Projectiles

 

Thanks for your answer James, but still I have some questions.

How can I translate this to C#?:

//velocities
Vector3 shooterVelocity = shooter.rigidbody ? shooter.rigidbody.velocity : Vector3.zero;
Vector3 targetVelocity = target.rigidbody ? target.rigidbody.velocity : Vector3.zero;

 

That is C#.

1 thing though, you can't use target.rigidbody property anymore so you will need to do a target.GetComponent<RigidBody>() instead

 

Thanks for your help, I almost done it, I just need a way to shoot to that Vector3 position. I just know how to use Instantiate, and I think that you can't do it using that...

That's what I have tried:

Quaternion aux = Quaternion.LookRotation (interceptPoint);
Instantiate(bolt, shotSpawn.position, aux);

But this is not working, it just shoots to a crazy position...

 

If you create a script called: Projectile.cs or something similar and attach it to your bolt.prefab you can do something like this:

Code (CSharp):

1. class Projectile : Monobehaviour
2. {
3.  
4.    public float speed = 10.0f;
5.    public Vector3 Direction{get;set;}
6.  
7.    void Update()
8.   {
9.     transform.position += Direction * (Time.deltaTime * speed);
10.   }
11.  
12.  
13. }

Then when instantiating:

Code (CSharp):

1. Projectile bullet = Instantiate(bolt, shotSpawn.position, Quaternion.Identity) as Projectile;
2.  
3. bullet.Direction =( interceptPoint - shotSpawn.position).normalized;

 

I had a script attached to the bolt with that code:

GetComponent<Rigidbody>().velocity = transform.forward * speed;

I'm trying what you told me but I'm getting a NullReferenceException error and the bolt is being instantiated but it's not moving. The errors are located in functions that reach the function where I calculate the interceptPoint and Instantiate the bolt, and in the line where I have ''bullet.Direction = (interceptPoint - shotSpawn.position).normalized;''..

 

Can you show the code attached to the bolt? I see now what you were trying to do with setting the initial rotation to look at the intercept point

 

Yes, sure.

Code (CSharp):

1.  
2. using UnityEngine;
3. using System.Collections;
4.  
5. class Mover : MonoBehaviour
6. {
7.     public float speed=1.1f;
8.     public GameObject explosion;
9.     public float lifeTime;
10.     public Vector3 Direction{get;set;}
11.  
12.     private bool destroyed=false;
13.  
14.     void OnTriggerEnter(Collider other){
15.         if (other.tag == "Blue Team") {
16.  
17.             return;
18.         }
19.         Destroy (gameObject);
20.         Instantiate (explosion, transform.position, transform.rotation);
21.         destroyed = true;
22.     }
23.  
24.     void Update(){
25.         if (!destroyed && Time.time>=lifeTime) {
26.             Instantiate (explosion, transform.position, transform.rotation);
27.             Destroy (gameObject);
28.         }
29.         transform.position += Direction * (Time.deltaTime * speed);
30.     }
31.  
32.     void Start ()
33.     {
34.         GetComponent<Rigidbody>().velocity = transform.forward * speed;
35.  
36.         lifeTime +=Time.time;
37.     }
38. }
39.  

I tried removing ''GetComponent<Rigidbody>().velocity = transform.forward * speed;'', but this is not causing the error.
And that's what I wrote in the shoot script:

Code (CSharp):

1.  
2. Mover bullet = Instantiate(bolt, shotSpawn.position, Quaternion.identity) as Mover;
3. bullet.Direction = (interceptPoint - shotSpawn.position).normalized;
4.  

Quaternion.Identity doesn't exist, that's why I wrote Quaternion.identity.