How to make a random occurrences using a timer?

Question

The game I'm making is mostly about randomization, you enter the scene, a random texture appears on an object, here is the code but it changes every second, I want it to change every time you enter the scene, if I get rid of yield and press play, unity goes grey and crashes.

 #pragma strict
 
 var textures: Texture2D[]; // assign some textures in the Inspector
  
 function Start (){
     while (true){
         renderer.material.SetTexture ("_MainTex", textures[Random.Range(0, textures.Length)]);
         yield WaitForSeconds(2.0);
     }
 }

I also want it so when you enter a scene a random number is chosen and then it begins to count down to 0 before ending the game. When I press play the random number is placed, then it goes straight to 0 instead of counting down from said number. I hope this is not too much to ask i'm fairly new.

 #pragma strict
 
 var timer : int;
 
 function Start () 
 {
     timer = Random.Range(10.0, 20.0);
 }
 
 function Update ()
 {
     timer -= Time.deltaTime;
     Debug.Log(timer);
     
     if(timer <=0)
     {
         timer = 0;
     }
 }

Answer 1

Answer by Eaneth · Sep 25, 2014 at 07:20 PM

Problem One: Don't use while loops, they've been known to crash Unity hard.

Problem Two: For the random events try this...

 var nextTime: float;
 var modifier : float;
 
 function Start()
 {
     nextTime = 0.0;
 }
 
 function Update()
 {
     //Get a random value
     modifier = Random.Range(10.0,20.0);
     
     //Set nextTime equal to current run time plus modifier
     nextTime = Time.time + modifier;
 
     //Check if current system time is greater than nextTime
     if(Time.time > nextTime)
     {
         //DO EVENT
     }
 }

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ALEGOMan · Sep 25, 2014 at 11:04 PM 0

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This seems to make both variables randomize any 2 digit number, it's hard to determine exactly what its doing, it seems to be counting up and randomizing at the same time over the 10,20 limit

Answer 2

Answer by Habitablaba · Sep 25, 2014 at 06:57 PM

To help solve the timer going straight to 0, start by making it a float instead of an int.

To help with the texture issue, simply remove the "while(true)" part. With it there, you are attempting to change the texture every frame, and you'll never leave the start method!

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ALEGOMan · Sep 25, 2014 at 07:18 PM 0

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Thanks for the help, it does count down now but the only problem I have now it that it has 8 tenths(0.00000000) instead of just a whole number, and the counter keeps going into the minus when I made the if statement for 'timer <=0' when it does this the counter counts down the last 3 tenths, pretty strange. http://puu.sh/bND5r/8dd7d4d049.png

Habitablaba · Sep 25, 2014 at 08:11 PM 0

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Yeah, that's floats for you, never quite what you want them to be.
A common solution for this is
timer = Mathf.Round(timer * 10) / 10;
This will give you one decimal points worth of precision, but will also keep your float from being something silly like 0.0000004
In addition, if you don't want the user to see the decimal places, you can cast it back to an int when you display it!

Answer 3

Answer by rutter · Sep 25, 2014 at 07:03 PM

 while (true)

That's an infinite loop. It never ends.

If your code runs asynchronously (such as a coroutine), that's okay because the program will be able to run while the coroutine is paused.

When you delete all yield statements in a function, it's no longer a coroutine. The loop was always infinite; the only difference now is that it keeps control of the main thread, too.

Infinite loop + blocking main thread = your program stops running.

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ALEGOMan · Sep 25, 2014 at 07:10 PM 0

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It was so obvious haha thanks!!

How to make a random occurrences using a timer?

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