c# - While loop freezes game in Unity3D

Question

I've always struggled with while loops because they barely ever work for me. They always cause my Unity3D application to freeze, but in this instance I really need it to work:

bool gameOver = false;
bool spawned = false;
float timer = 4f;

void Update () 
{
    while (!gameOver)
    {
        if (!spawned)
        {
            //Do something
        }
        else if (timer >= 2.0f)
        {
            //Do something else
        }
        else
        {
            timer += Time.deltaTime;
        }
    }
}

Ideally, I want those if statements to run as the game runs. Right now it crashes the program and I know it's the while loop which is the problem because it freezes anytime I uncomment it out.

Answer 1

If you want to use a variable to control a while loop and wait in that while loop then do it in a coroutine function and yield after each wait. If you don't yield, it will wait too much and Unity will freeze. On mobile devices like iOS, it would crash.

void Start()
{
    StartCoroutine(sequenceCode());
}

IEnumerator sequenceCode()
{
    while (!gameOver)
    {
        if (!spawned)
        {
            //Do something
        }
        else if (timer >= 2.0f)
        {
            //Do something else
        }
        else
        {
            timer += Time.deltaTime;
        }

        //Wait for a frame to give Unity and other scripts chance to run
        yield return null;
    }
}