C# how to Make function/Method Wait without blocking program (Unity)

Question

I want to simulate health regeneration in my game in unity, in the function RestoreHealth().

Am I overthinking it by wanting to create a child process, so when I call wait, it won't affect any current running process or thread and the child process will die when the function is done.

public void RestoreHealth() {
    if (health >= MaxHealth) return; // health and MaxHealth are Class variables

    if (health % 10 != 0) {     // if health is not dividable by 10
        int temp = health % 10; // then we round it to the closest 
                                //tenth
        temp = 10 - temp;
        health += temp;
    }

    int i = health;

    for (; i < MaxHealth; i += 10) {  // where the health grows till 100
        health += 10;
        // sleep(1000);  // make function wait for '1 second' to iterate again

        Debug.Log("Health: " + health);
    }
}

How do I create a child process in C# or unity in this case and cause it to wait?

Is there an equivalent to Fork(); like in C?

Also, this function is called when the player initially receives damage.

Solution:

note: I changed Health to Armour

public IEnumerator RestoreArmour() {
        while (_Armour < _MaxArmour) {
            _Armour++;
            Debug.Log("Health: " + _Armour);
            yield return new WaitForSeconds(ArmourRegenRate); // ArmourRegenRate is a 
                                                             // float for the seconds
        }
    }

and use this to initiate the coroutine

 void Start(){

    StartCoroutine(player.RestoreArmour());
}

fork() doesn't create a process. It creates a thread. Yes, you can create threads in C#. — user47589
– user47589, Commented May 17, 2019 at 20:51
In unity you can't create threads because unity only runs on the main thread for multi-threading you would have to use a server and query the server to perform actions @Amy — CoderJoe
– CoderJoe, Commented May 17, 2019 at 20:53

Fredrik · Accepted Answer · 2019-05-19 12:42:14Z

5

Basic Coroutine concept

In Unity you work with Coroutines to achieve this asychronous "threaded" behaviour

IEnumerator RestoreHealth() {
   while (health != MaxHealth) {
       health++;
       yield return new WaitForEndOfFrame();
   }
}

and then invoke it with

StartCoroutine(RestoreHealth());

Restarting a Coroutine

In order to stop an existing Coroutine from running and start a new one, this is how you would achieve that:

private Coroutine _myCoroutine = null;

void SomeMethod()
{
    if (_myCoroutine != null)
        StopCoroutine(_myCoroutine);

    _myCoroutine = StartCoroutine(SomeOtherMethod());
}

Pausing armor restoration for X seconds when player has taken damage

A common functionality is to have something restore armor when player hasn't taken damage for X seconds:

private bool _shouldRestoreArmour = true;
private Coroutine _pauseArmorCoroutine = null;

void Update()
{
    if (_shouldRestoreArmour)
        Armor += ArmorRegenerationPerSecond * Time.deltaTime;
}

void PlayerTakeDamage() 
{
    if (_pauseArmorCoroutine != null) 
        StopCoroutine(_pauseArmorCoroutine);

    _pauseArmorCoroutine = StartCoroutine(PauseRestoreArmor());

    // Take damage code
}

IEnumerator PauseRestoreArmor()
{
    _shouldRestoreArmor = false;
    yield return new WaitForSeconds(RESTORE_ARMOR_DELAY_TIME);
    _shouldRestoreArmor = true;
}

Here the player will regenerate armor at all times, except for X seconds after the player has taken damage. If the player takes damage multiple times we will simply abort the previous coroutine and start a new one, so that it will be a fresh X seconds from the last hit.

edited May 19, 2019 at 12:42

answered May 17, 2019 at 21:20

Fredrik

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6 Comments

Elfonz Over a year ago

I replace 'WaitForEndOfFrame(); with 'yield return new WaitForSeconds(ArmourRegenRate); ' instead

Fredrik Over a year ago

Great! Whatever works for you, I just wanted to show the concept here. Remember that these things are asynchronous, meaning you should make sure to only start ONE of these at the time, unless you need multiple of the running asynchronously, of course.

Fredrik Over a year ago

I see the update in your original post; that implementation looks great!

Elfonz Over a year ago

hmm, so this RestoreArmour() function would be called every time the player is Damaged, if the player gets hit again while the armour is regenerating, then it would be bad, i need to halt the current running function and restart it

Fredrik Over a year ago

Ah, yes. A common use-case; a debouncer functionality. I'll update my code to show you how I usually implement this. 1 sec

|

CoderJoe · Accepted Answer · 2019-05-17 21:19:40Z

0

You can create a timer assuming that you run this in the update method

private float timer = 1;
private float timerReset = 1;

private void Update(){
  RestoreHealth();
}

public void RestoreHealth() {
  if (health >= MaxHealth) return; // health and MaxHealth are Class variables

  if (health % 10 != 0) {     // if health is not dividable by 10
    int temp = health % 10; // then we round it to the closest tenth
    temp = 10 - temp;
    health += temp;
  }
  int i = health;
  for (; i < MaxHealth; i += 10) {  // where the health grows till 100
    if(timer > 0){
      timer -= 1 * time.deltaTime;
    }else{
      health += 10;
      Debug.Log("Health: " + health);
      timer = timerReset;
    }
  }

}

or you can simply just give your player 1 health every second or whatever amount for instance

    public void RestoreHealth() {
      if (health >= MaxHealth) return; // health and MaxHealth are Class variables

      if (health % 10 != 0) {     // if health is not dividable by 10
        int temp = health % 10; // then we round it to the closest tenth
        temp = 10 - temp;
        health += temp;
      }
      int i = health;
      for (; i < MaxHealth; i += 10) {  // where the health grows till 100

          health += 10 * 1 * time.deltaTime;
          Debug.Log("Health: " + health);
          timer = timerReset;

      }

    }

So in this scenario your player recieves 10 health every second but the value will always go up so in the matter of a second the player health would go up 1 health every 100ms

edited May 17, 2019 at 21:19

answered May 17, 2019 at 20:57

CoderJoe

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3 Comments

Elfonz Over a year ago

won't this be an infinite loop because the timer is always reset to 1? also, this function is called when the player initially receives damage.

CoderJoe Over a year ago

It only gets reset once the timer has counted down all the way to zero then it is reset

Elfonz Over a year ago

yeah i works but i want a more noticeable slow increment. thanks though

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C# how to Make function/Method Wait without blocking program (Unity)

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