Enemy fire every few seconds

Question

Hi I'm trying to get my enemy to fire once every few seconds, I tried using a Coroutine but due to me essentially calling the Coroutine through the update method, the Coroutine is repeating every frame update and spamming the shoot key. What is a solution for this?

void Update () {
        Shoot ();
}

public void Shoot(){

        StartCoroutine ("ShootContinuous");

}

public IEnumerator ShootContinuous() {
    yield return new WaitForSeconds (1);
    anim.SetTrigger("Shoot");
    Instantiate (Bullet, firePoint.position, firePoint.rotation);
    isShooting = true;
    yield return new WaitForSeconds (1);
    anim.SetTrigger("NoShoot");
    isShooting = false;

}

Answer 1

I've found that making a looping script works well for an attack timer, and avoids the problems that come with using a coroutine to time something. Bonus here is that you can use this anywhere in your scripts for an easy timer.

private bool canAttack; //This gets changed when the enemy can try and shoot at you (ie. within range)

private float newFireTime; //This holds the time for the next shot
private float stopFireTime; //Holds the time for when you want to change your anim
private float firingDelay; //The delay in seconds you set (ie a value of "2" means 1 shot every 2 seconds)

private bool attackLoopStarted;

void Update()
{
    if(canAttack)
    {
        AttackTimer();
    }
}

private void AttackTimer()
{
    if (!attackLoopStarted) //If the attack loop has not been initiated
    {
        attackLoopStarted = true; //Signal the loop has been started
        newFireTime = Time.time + (1 / fireRate); //Takes your fire delay in seconds and converts it to shots Per second and record this
        stopFireTime = Time.time + (1 / stopFireTime); // Same as above, except for your animation
        Shoot(); //Call your method to initiate an attack
    }

    if (attackLoopStarted) //Once the attack loop has started check the time against the future time
    {
        //If the gametime is greater than or equal to the newFireTime, then set the bool to false to restart the loop
        if (Time.time >= newFireTime) 
        {
            attackLoopStarted = false;
        }
        //Will only check when isShooting is true, will change the aniamtion after your specified time
        else if (Time.time >= stopFireTime && isShooting == true) 
        {
            StopShoot(); //Call method to change your anim and set the isShooting bool to false
        }
    }
}

private void Shoot()
{
    anim.SetTrigger("Shoot");
    Instantiate(Bullet, firePoint.position, firePoint.rotation);
    isShooting = true;
}

private void StopShoot()
{
    anim.SetTrigger("NoShoot");
    isShooting = false;
}

Edit: This exact code will present a bug if your fire delay, and the delay for your animation are exactly the same (say you want to shoot every 2 seconds and you want the animation to change every 2 seconds at the exact time of the shot, which would probably work against what I believe you are trying to accomplish). You can fix that by replacing stopFireTime = Time.time + (1 / stopFireTime); with stopFireTime = Time.time + (1 / fireRate / 2);that will casue the animation to change back from firing to not firing 1/2 way between shots.

Answer 2

If you don't want them stacking up, just use a bool for a flag.

bool inShootingLoop = false; //keep track of when the coroutine is running

public void Shoot(){
    if(!inShootingLoop)
        StartCoroutine ("ShootContinuous");
}

public IEnumerator ShootContinuous() {
    inShootingLoop = true; //we're running, set this to make sure we don't start again
    yield return new WaitForSeconds (1);
    anim.SetTrigger("Shoot");
    Instantiate (Bullet, firePoint.position, firePoint.rotation);
    isShooting = true;
    yield return new WaitForSeconds (1);
    anim.SetTrigger("NoShoot");
    isShooting = false;
    inShootingLoop = false; //we're done, set this to allow another iteration
}

Or you can just run your coroutine forever:

public IEnumerator ShootContinuous() {
    while(true) {
        yield return new WaitForSeconds (1);
        anim.SetTrigger("Shoot");
        Instantiate (Bullet, firePoint.position, firePoint.rotation);
        isShooting = true;
        yield return new WaitForSeconds (1);
        anim.SetTrigger("NoShoot");
        isShooting = false;
    }
}

Answer 3

The problem is that the ShootContinuous() Coroutine is in Shoot() and Shoot() is in Update() which means the Coroutine ShootContinuously is in Update(). So a new ShootCountinuously() Coroutine is started for every frame. The below method starts only one Coroutine which will repeat Continuously.

void Start () 
{
   Shoot ();
}

public void Shoot()
{
    StartCoroutine (ShootContinuous());
}

public IEnumerator ShootContinuous() 
{
    while(true)
    {
        yield return new WaitForSeconds (1);
        anim.SetTrigger("Shoot");
        Instantiate (Bullet, firePoint.position, firePoint.rotation);
        isShooting = true;
        yield return new WaitForSeconds (1);
        anim.SetTrigger("NoShoot");
        isShooting = false;
    }
}

Note: Never start a coroutine in Update()