Waiting for seconds in Update()

Since you can't use "yield new WaitForSeconds()" in the Update() function what is the best way to make something pause for 1 second instead of firing off every frame?


Thanks

 

1. don't use update. it will be called on each frame
2. Use Startcoroutine and start it in "Start". Make it yield for a second or whatever timeframe you want

 

Right. I understand that but the problem is that I need to run it when a touch happens on the iPhone so it needs to run from update().

 

Something like this?

Code (csharp):

1. private bool beingHandled = false;
2.  
3. public void Update()
4. {
5.     if( /*some case  */ !beingHandled )
6.     {
7.         StartCoroutine( HandleIt() );
8.     }
9. }
10.  
11. private IEnumerator HandleIt()
12. {
13.     beingHandled = true;
14.     // process pre-yield
15.     yield return new WaitForSeconds( 1.0f );
16.     // process post-yield
17.     beingHandled = false;
18. }

 

Ive tried this. Here is my code... Can anyone see why it's not waiting and just keeps counting down as fast as the frames?

Code (csharp):

1.  
2.  
3. function ReduceFuel(){
4.  
5.     while(FuelLevel > 1)
6.     {
7.        
8.         FuelLevel -= 1;
9.         yield new WaitForSeconds(1);
10.        
11.     }  
12.  
13. }
14.  
15. function Update () {
16.        
17.    
18.     for (var evt : iPhoneTouch in iPhoneInput.touches)
19.     {
20.        
21.         var element : GUIElement = guiLayer.HitTest (Input.mousePosition);
22.        
23.        
24.             if (evt.phase == iPhoneTouchPhase.Stationary)
25.             {
26.  
27.                         if(element == ArrowUp || element == ArrowDown)
28.                         {  
29.                            
30.                                 ReduceFuel();
31.                                
32.                         }
33.                
34.             }
35. }
36.  
37.  

 

The reason that isn't working as you'd expect is that ReduceFuel isn't running as a coroutine. As AngryAnt suggested, you should start it as a coroutine:

Code (csharp):

1. StartCoroutine(ReduceFuel());

 

I was thinking a coroutine was just a function. Whats the difference between a coroutine and a function?

 

I think it is one of these
http://msdn.microsoft.com/en-us/library/system.collections.ienumerator.aspx

 

A coroutine is a function which will be continuously executed over several frames - depending on how you yield it. All coroutines are executed after the last update call and when you yield, the function ends - only to be re-run from the point of the yield statement once the yield statement has been "completed".

 

I'm using Javascript and not C#. I think I remember reading in the docs that you had to call co-routines for C# but that Javascript automatically would do this when you call a function.

 

Have a look at the script reference (my best friend) for information on coroutines and the yield statement. At the bottom of the page it says:

So you do need to use StartCoroutine when calling from Update.

 

Ok, I did this and still get the same result:

Code (csharp):

1.  
2.  
3.        
4.             if (evt.phase == iPhoneTouchPhase.Stationary)
5.             {
6.  
7.                         if(element == ArrowUp || element == ArrowDown)
8.                         {  
9.                            
10.                                 StartCoroutine(ReduceFuel());
11.                                
12.                         }
13.                
14.             }
15.  
16.  

[/quote]

 

I guess I should have put all the code.....this is what I have now and it still does not waitforseconds....wierd....

Code (csharp):

1.  
2.  
3.  
4.  
5. function ReduceFuel(){
6.  
7.     while(FuelLevel > 1)
8.     {
9.        
10.         FuelLevel -= 1;
11.         yield new WaitForSeconds(5);
12.        
13.     }  
14.  
15. }
16.  
17. function Update () {
18.    
19.        
20.     //PlayWarnings();      
21.    
22.     for (var evt : iPhoneTouch in iPhoneInput.touches)
23.     {
24.        
25.         var element : GUIElement = guiLayer.HitTest (Input.mousePosition);
26.        
27.        
28.             if (evt.phase == iPhoneTouchPhase.Stationary)
29.             {
30.  
31.                         if(element == ArrowUp || element == ArrowDown)
32.                         {  
33.                            
34.                                 StartCoroutine(ReduceFuel());
35.                                
36.                         }
37.                
38.             }
39.  
40. }
41.  
42.  
43.  
44.  

 

Since you're using JScript, you should drop the new keyword in your WaitForSeconds line:

Code (csharp):

1. yield WaitForSeconds(5);

You only need new in C# code (where yield statements get rather complicated).

 

I've actually used the keyword new throughout my entire game and it's worked as i've wanted it too. I went ahead and tried it without it as you suggested and it still isn't working ... any other suggestions?

 

Not with Javascript, where it does that for you. The only reason to use StartCoroutine in Javascript is if you want to be able to use StopCoroutine on the routine you're starting.

--Eric

 

Thats what I sorta remembered reading..... Eric, do you have any suggestions to pull this off? It seems like anything I call in Update() acts as if it were in Update().


What I'm trying to accomplish is a steady fuel consumption as long as the button is being pushed.

 

What you probably want to do is multiply the amount by Time.deltaTime so that you get a constant rate regardless of frame rate. You can do this inside the Update function:

Code (csharp):

1. fuelLevel -= Time.deltaTime * ratePerSecond;

As for the issue of coroutines, JScript and Update, there is a discrepancy in the documentation. The description for StartCoroutine does clearly state that:

Yet the overview does say to use StartCoroutine to start a function from Update to use a yield statement. There is some issue here, hopefully Eric or one of the Unity gods has an answer!

 

Good thought.....problem is, I've tried that too and it doesn't work either. I plugged your code and tried again using various ratesPerSecond and no matter what it is the numbers still count down per frame.

 

Is there any other part of your code that accesses fuelLevel? If you set the ratePerSecond to 0.2, that would be the same as 1 unit per 5 seconds, but you'll see it drop continuously while the button is pressed. You're saying that you press the button and it is dropping at a rate of 1 unit per frame?

 

That's correct, but remember that you don't need to explicitly write StartCoroutine in Javascript, so there isn't any contradiction there. You're still using StartCoroutine; it's just implicit.

You probably need to do what AngryAnt said and use a "beingHandled" boolean or something similar to check if the coroutine is already running, and block any further calls if so. Because the way it is now, you'd be starting the coroutine once per frame in every Update call, so in short order you'd have it running many times per second.

--Eric

 

Yep, Tried that too. But....tried it again.....here's the code...maybe somethings not right in my logic..

Code (csharp):

1.  
2.  
3. var FuelIsRunning : boolean = false;
4.  
5. function ReduceFuel(){
6.  
7.    
8.     while(FuelLevel > 1  FuelIsRunning == true)
9.     {
10.        
11.         FuelLevel -= 1;
12.         yield WaitForSeconds(1);
13.     }  
14.  
15. }
16.  
17. function Update () {
18.            
19.    
20.     for (var evt : iPhoneTouch in iPhoneInput.touches)
21.     {
22.        
23.         var element : GUIElement = guiLayer.HitTest (Input.mousePosition);
24.        
25.        
26.             if (evt.phase == iPhoneTouchPhase.Stationary)
27.             {
28.  
29.                         if(element == ArrowUp || element == ArrowDown  FuelIsRunning == false)
30.                         {  
31.                                 FuelIsRunning = true;
32.                                 ReduceFuel();
33.                                
34.                                
35.                         }
36.                
37.             }
38.  
39.         if (evt.phase == iPhoneTouchPhase.Ended)
40.             {
41.                
42.                 if(element == ArrowUp)
43.                     {
44.                        
45.                         FuelIsRunning = false;
46.                    
47.                     }
48.        
49.                 if(element == ArrowDown)
50.                     {
51.                         FuelIsRunning = false;
52.                                
53.                     }
54.    
55.             }
56.            
57.                            
58.        
59.     }
60.  
61.  
62.  
63.  
64.  

 

All you should need is this:

Code (csharp):

1.  
2. function Update () {
3.     for (var evt : iPhoneTouch in iPhoneInput.touches)
4.     {
5.         var element : GUIElement = guiLayer.HitTest (Input.mousePosition);
6.         if (evt.phase == iPhoneTouchPhase.Stationary)
7.         {
8.             if (element == ArrowUp || element == ArrowDown)
9.             {  
10.                 FuelLevel -= Time.deltaTime * 0.2;
11.             }
12.         }
13.     }
14. }
15.  

But you tried that and it didn't work?

 

Yes, I tried this again and it doesn't work. Does anyone else have any suggestions?

 

Your code snippet doesn't show where you declared/defined FuelLevel and its starting value. Could you post that as well? Or check to make sure its a float value, not an integer.

 

Well, Actually it was a int and I didn't catch that....but....I changed it and it's still not working.

 

Stop the presses....I changed the wrong var. That was the problem the entire time...... ok, now I feel like an idiot.

 

Still funny 6 months later

 

Still funny 5 years later

 

Dont understand but still funny and usefull 7 years later

 

I read somewhere that calling coroutine function in Update makes a huge performance issue.

 

Starting a coroutine from Update should not cause performance issues.
A problem would be to start the same coroutine each time Update is invoked, that is on each frame. But that would be considered a bug.

Do you still have a reference to what you've read?
What do you want to do with coroutines?

 

Unfortunately i don't remember the reference .

 

https://github.com/maazirfan/WaitForSeconds-function-in-C-

 

I wanted to wait x Seconds in the Update() before continuing. So you cannot use the yield there (don't want to start a coroutine every frame right?)

So if someone, like me, searched this / needs this in and for the Update():

Code (CSharp):

1. private float timer = 0;
2.  
3. private float timerMax = 0;
4.  
5. void Update ()
6. {
7.    text += "Allow yourself to see what you don’t allow yourself to see.";
8.  
9.    if(!Waited(3)) return;
10.  
11.    text += "\n\nPress any key!";
12. }
13.  
14.  
15. private bool Waited(float seconds)
16. {
17.     timerMax = seconds;
18.  
19.     timer += Time.deltaTime;
20.  
21.     if (timer >= timerMax)
22.     {
23.         return true; //max reached - waited x - seconds
24.     }
25.  
26.     return false;
27. }

 

Thanks!!!

 

why cant unity create a simple wait function in monodevelop

 

There are coroutines for that, or simply a timer/counter in Update(). Or even Invoke, in some circumstances.

 

I could be wrong, but if you're waiting for something to be touched, couldn't you use drag or pointer events, to eliminate update out of the equation..?

Then use that to invoke or start coroutine?

It's not much, I know, but it would eliminate an unnecessary "if button pressed" check 50-100 times per second when it's not needed, wouldn't it?

I think you can control how long/often an event like that fires too, can't you?

 

Bravo

 

still funny 10 years later.
don't worry happens with everyone

 

I pasted everything as You wrote but my beingHandled bool instantly changes to true (it is not waiting 3 seconds)

 

That's what it's supposed to do: Whenever it gets switched to true, it switches back to false after 3 seconds.

P.S. I can scratch "posting in a 10 year old thread" of my unity bucket list now, but I assume you had that problem today

 

Still funny in CoronaTimes

 

Dude, you're still saving lives.... Thank you!

 

perfectly works in my project, Thank you:

Code (csharp):

1.  
2.  public void Update()
3.     {
4.         if (!beingHandled)
5.         {
6.             StartCoroutine(DataRequest());
7.         }
8.     }
9.  
10.     private IEnumerator DataRequest()
11.     {
12.         beingHandled = true;
13.         // process pre-yield
14.         yield return new WaitForSeconds(30.0f);
15.         // process post-yield
16.         StartCoroutine(RestClient.Instance.Get(WEB_URL, HandleResult));
17.         beingHandled = false;
18.  
19.         void HandleResult(OpenSkyResult result)
20.         {
21.  
22.             foreach (OpenSkyState state in result.states)
23.             {
24.                 GameObject plane = Instantiate(planePrefab) as GameObject;
25.                 LatLon2Unity planeScript = plane.GetComponent<LatLon2Unity>();
26.                 planeScript.areaRight = ctpd.areaRight;
27.                 planeScript.areaLeft = ctpd.areaLeft;
28.                 planeScript.areaTop = ctpd.areaTop;
29.                 planeScript.areaBottom = ctpd.areaBottom;
30.                 planeScript.areaWidth = ctpd.areaWidth;
31.                 planeScript.areaLength = ctpd.areaLength;
32.                 planeScript.destinationLat = state.latitude;
33.                 planeScript.destinationLon = state.longitude;
34.             }
35.         }
36.     }
37. }
38.