why do projectiles always move to the same spot?

Scripting
1

Hi, i have a simple first person shooter, and i have a gun which creates projectiles. the projectiles should be moving to an empty in front of it, but instead are moving to a single spot. Can anyone see anything wrong:

using UnityEngine;
using System.Collections;

public class WeaponHold : MonoBehaviour {

    public GameObject lefthand;
    public GameObject righthand;
    public GameObject parent;

    public GameObject pump;
    public GameObject handle;

    public GameObject projectile;
    public GameObject lookdirection;

    public float pumpspeed;
    private bool isPumping;
    private bool isReverse;
    private float progress;
   
    void Start () {
        isPumping = false;
        isReverse = false;
    }

    void Update () {
        if (Input.GetKeyDown (KeyCode.Mouse0) && !isPumping) {
            int i = 0;
            while (i < 10){
                Instantiate(projectile);
                projectile.transform.position = this.gameObject.transform.position;
                i++;
            }
            isPumping = true;
            progress = 1;
        }
        lefthand.transform.position = pump.gameObject.transform.position;
        righthand.transform.position = handle.gameObject.transform.position;
        lefthand.transform.LookAt (pump.transform.position);
        righthand.transform.LookAt (handle.transform.position);
        if (isPumping) {
            if (!isReverse) {
                pump.transform.Translate (0,(float) -0.1, 0);
                progress = progress - (float) 0.1;
                if (progress < 0) {
                    isReverse = true;
                    progress = 1;
                }
            }
            if (isReverse) {
                pump.transform.Translate (0,(float) 0.1, 0);
                progress = progress - (float) 0.1;
                if (progress < 0) {
                    isReverse = false;
                    isPumping = false;
                }
            }
           
        }
    }
}

using UnityEngine;
using System.Collections;

public class ProjectileScript : MonoBehaviour {

    public GameObject lookdirection;

    void Start () {
        this.gameObject.transform.LookAt (lookdirection.transform.position);
        this.gameObject.transform.Rotate (0, 90, -270);
    }
   

    void Update () {
        this.gameObject.transform.Translate (0,(float) 0.1, 0);
    }
}

Here’s a screenshot of the error:
I have selected the transform where it should be travelling to

2347066--158870--Error.jpg
2347066--158870--Error.jpg1438×899 245 KB

2

I see one possible cause: this line-

this.gameObject.transform.LookAt(lookdirection.transform.position);

“LookAt” is going to use the current position of the object when computing the new rotation. But you don’t set the position of the projectile until AFTER you have called this.

3

So, where should this be?

4

So I`ve fallen into this trap many times :

Here you are changing the position of a prefab and NOT the instantiated object.
Instead do this :

GameObject obj = Instantiate(projectile);
obj.transform.position = transform.position;
2 Likes
5

That looks better, and i’m sure that it would have caused a problem if u hadn’t told me (thanks :slight_smile: ), but it still isn’t working >.< it won’t point towards my point.

6

I also agree that you should not be calling LookAt in the start function, or rotating the obj for that matter. Its better to have your obj as a child of a blank object. Set your childed objects rotation in he prefab, and make sure the parents Z axis is point in the world Z direction. then when you spawn the object, you can do something like this :

//in projectile script
Vector3 targetPosition;
float speed = 1;

//target position sent from WeaponHold  script
public void Initialize(Vector3 targetPos)
{
    targtePosition = targetPos;
    Vector3 direction = targetPos - transform.position;
    Quaternion rot = Quaternion.LookRotation(direction);
    transform.rotation = rot;
}

void Update()
{
    //this is straight from the manual
    float step = speed * Time.deltaTime;
     transform.position = Vector3.MoveTowards(transform.position, targetPosition, step);
}