koobas.hobune.stream
Random InitState not working with Coroutines / IEnumerator?
Hi!
When you first start our game, world objects such as houses are instantiated in random positions using a given seed.
The idea was to save the seed, then use Random.InitState(seed) to re-generate the same layout the next time the game is played.
The issue is that it doesn't seem to work with coroutines.
If I use InitState via FixedUpdate it works as expected, but our prefab instantiation is done via coroutines to prevent the game "freezing" while everything is placed down.
Here's a quick example script to show the issue.
This code SHOULD give the same 4 numbers each time you click "Run".
But if you click "Run" a bunch of times and you'll start to inconsistent results.
using System.Collections;
using UnityEngine;
public class randomTest: MonoBehaviour
{
public bool run = false;
public IEnumerator RandomNumbers()
{
int iteration = 0;
int xIterations = 4;
Random.InitState(255);
for (int x = 0; x < xIterations; x++)
{
iteration++;
Debug.Log(iteration.ToString()+" = "+Random.Range(0,100));
}
}
private void FixedUpdate()
{
if(run)
{
run = false;
StartCoroutine("RandomNumbers");
}
}
}
I've been struggling with this all day. It SHOULD work but simply doesn't.
My best bet is something to do with timing, but even adding a WaitForFixedUpdate or WaitForEndOfFrame doesn't seem to help.
Please let me know if you can help!
I'm not sure why, but removing "yield return null" seems to fix this issue.
I have no idea if this is a glitch with coroutines, a timing issue or something else but I guess my issue is solved.
Sadly the whole point of yield was to prevent game "freezes" while instantiating multiple game objects, but I'll sacrifice it for consistent results.
You need to prevent the Coroutine from running if it's already running.
Try adding an _isRunning toggle.
public bool run = false;
private bool _isRunning = false;
public IEnumerator RandomNumbers()
{
int iteration = 0;
int xIterations = 4;
Random.InitState(255);
for (int x = 0; x < xIterations; x++)
{
iteration++;
Debug.Log(iteration.ToString()+" = "+Random.Range(0,100));
yield return null;
}
_isRunning = false;
}
private void FixedUpdate()
{
if(run && !_isRunning)
{
run = false;
_isRunning = true;
StartCoroutine("RandomNumbers");
}
}
I tried the code you pasted but I'm still having the issue as you can see here:
As you can see, it's not super-common but it's enough to make things entirely unreliable.
