My Countdown function seems to go crazy in the Update function but works fine for the first time in the Start function. Help?

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This is from the Walker Boys tutorial, game 1.

I have assigned the script to two objects and I want a specified one to as the counter ticks down and then to reappear and change its position when the countdown goes to zero. However, the function I pasted below seems to be working peculiarly. When I apply it in the start() function, it seems to work fine. The object blinks and then reappears in another place, but since it is the start function, it only does that when I start the game. Now, when I put my Countdown1() function (shown below) in the Update() function, the object seems to disregard the counter and starts to appear randomly, switching its position multiple times and refusing to stay still and blink until the counter ends.

Since I am a beginner, I have very much exhausted the knowledge available to me and have been at this for quite a while. Some tips would be great.

 function Countdown1()
 {
     while (countdown2 > 0)
     {
         yield WaitForSeconds(0.3);
         sphereDisappear.renderer.enabled = false;
         yield WaitForSeconds(0.3);
         sphereDisappear.renderer.enabled = true;
         countdown2--;
     }
     
 
     if (countdown2 == 0)
     {
         countdown2 = 3; 
         var newPosition = Vector3(Random.Range(-4, 4), Random.Range(-4, 4), 0);
         sphereDisappear.transform.p    osition = newPosition;
     }

Answer 1

Answer by tw1st3d · Jul 10, 2013 at 07:45 PM

The Update() method can not yield. I believe you have to use a Coroutine to do that.

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Julien-Lynge · Jul 10, 2013 at 07:54 PM 1

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I'm pretty sure you can yield from within Update:

http://docs.unity3d.com/Documentation/ScriptReference/index.Coroutines_26_Yield.html (also see various Q&A from UnityAnswers).

Perhaps you're thinking of C#, where you cannot define Update as an IEnumerator.

You don't want to yield from within Update, because you'd be spawning a new Coroutine every, well, update, and that wouldn't be good. That's what this poster is seeing: every Update (30, 60, perhaps more times per second) he/she is starting a new countdown. With many, many countdowns running, yeah, you're going to see weird behaviour.

You need to find a way to start a countdown only when certain conditions are met, so it doesn't launch every frame.

bamabhaa123 · Jul 11, 2013 at 04:17 PM 0

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I tried putting the if statement inside the while loop itself and on first look, it seems to work. However, the teleportation of the object is very inconsistent. At times it seems to teleport after exactly three seconds as written but sometimes it teleports after one or two seconds.

Answer 2

Answer by fafase · Jul 11, 2013 at 04:21 PM

Your start method only calls once and then no more.

Your update will call this on every frame.

You need to trigger the call when something happens, collisions, state of a variable, input...

 function Update()
 {
    if(something){
       Countdown1();
       reset something to something else to prevent new calls
    }
 }

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My Countdown function seems to go crazy in the Update function but works fine for the first time in the Start function. Help?

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