Trying to launch a projectile towards a gameobject, doesn't move!=

Question

I'm making a 2D Tower Defense game and want my towers to launch a prefab at minions. However it currently only spawns my desired prefab, but doesn't move it.

My two scripts:

public class Attacker : MonoBehaviour {

// Public variables
public GameObject ammoPrefab;
public float reloadTime;
public float projectileSpeed;

// Private variables
private Transform target;


// Use this for initialization
void Start () {
}

// Update is called once per frame
void Update () {

}
void OnTriggerEnter(Collider co){
    if (co.gameObject.tag == "Enemy" || co.gameObject.tag == "BlockTower") { 
        Debug.Log("Enemy tag detected");

        if(this.gameObject.tag == "Enemy" && co.gameObject.tag != "Enemy"){
            Debug.Log("This is an Enemy");
            // Insert for Enemey to attack Block Towers.
        }
        if(this.gameObject.tag == "Tower" && co.gameObject.tag != "BlockTower"){
            Debug.Log("This is a Tower");
            Tower Tower = GetComponent<Tower>();
            Tower.CalculateCombatTime(reloadTime, projectileSpeed);
            Transform SendThis = co.transform;
            Tower.SetTarget(SendThis);
        }
    }
}

}

and

public class Tower : MonoBehaviour {
private Transform target;
private float fireSpeed;
private double nextFireTime;
private GameObject bullet;
private Attacker source;

// Use this for initialization
public virtual void Start () {
    source = this.GetComponent<Attacker> ();
}

// Update is called once per frame
public virtual void Update () {

    if (target) {
        Debug.Log("I have a target");
        //if(nextFireTime <= Time.deltaTime)
        FireProjectile ();
    }
}
public void CalculateCombatTime(float time, float speed){
    Debug.Log("Calculate Combat Speed");
    nextFireTime = Time.time + (time * .5);
    fireSpeed = speed;
}
public void SetTarget(Transform position){
    Debug.Log("Set Target");
    target = position;
}
public void FireProjectile(){
    Debug.Log("Shoot Projectile");
    bullet = (GameObject)Instantiate (source.ammoPrefab, transform.position, source.ammoPrefab.transform.rotation);
    float speed = fireSpeed * Time.deltaTime;
    bullet.transform.position = Vector3.MoveTowards (bullet.transform.position, target.position, speed);
}

}

Basicly Attacker detects the object that collides with it, then if its tag is Tower it will send the information to Tower. My debug shows that every function works, even "Debug.Log("Shoot Projectile");" shows up.

However it doesn't move towards my target so I guess "bullet.transform.position = Vector3.MoveTowards (bullet.transform.position, target.position, step);" is never being executed?

Answer 1

Vector3.MoveTowards only moves the object once, it's just a instant displacement when the FireProjectile is called.

You need to create some kind of projectile script with an Update() function to make it move over time.

Here is an example:

public class Projectile : MonoBehaviour
{
    public Vector3 TargetPosition;

    void Update()
    {
        transform.position = Vector3.MoveTowards(transform.position, TargetPosition, speed * Time.DeltaTime);
    }
}

Then right after your bullet instantiation, set the target:

bullet.GetComponent<Projectile>().TargetPosition = target.position;

Hope it helps.