How to check if a minute has passed?

Unity Engine
,
1

I am trying to make a simple background swap every 60 seconds. I try to do this by checking if a minute has passed with a timer variable. Is it because I am using a float for the timer, instead of an int? If so, how do I make this script work with an integer?

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using TMPro;

public class DayNightCycle : MonoBehaviour
{
   
    public TextMeshProUGUI text;
    public GameObject daybg;
    public GameObject nightbg;
    private float timer;
   

    void Start()
    {
        nightbg.SetActive(false);
    }
   
    void Update()
    {
        timer += Time.deltaTime;
       
        if(timer % 60== 0)
        {
            nightbg.SetActive(true);
            daybg.SetActive(false);
        }
       
    }
}
2

Yes your timer will never exactly equal 60 or multiples thereof. You should not use an integer. You should do something like this:

float interval = 60;
void Update()
{
    timer += Time.deltaTime;
    if(timer >= interval)
    {
        timer -= interval;
        nightbg.SetActive(true);
        daybg.SetActive(false);
    }
}
2 Likes
3

Great, now how would I have these two backgrounds switch between each other every minute? I’m new and this is my best guess. It doesn’t work though.

void Update()
    {
        timer += Time.deltaTime;
       
        if(timer >= interval)
        {
            timer -= interval;
            nightbg.SetActive(true);
            daybg.SetActive(false);
        }
        if (timer >= interval)
        {
            timer -= interval;
            nightbg.SetActive(false);
            daybg.SetActive(true);
        }
    }

?

4

Something like this would do:

nightbg.SetActive(!nightbg.activeSelf); // invert the active state of the night bg
daybg.SetActive(!nightbg.activeSelf); // day should be on when night is off and vice versa
1 Like
5

Thanks you very much! This makes sense. :slight_smile:

6

Uhh, double negation is confusing :slight_smile: I would base the day / night state on the day background and would switch them like this:

nightbg.SetActive(daybg.activeSelf);
daybg.SetActive(!daybg.activeSelf);

It does the same thing but may be a bit less confusing. Though a better solution would probably be to use an actual variable to track the day / night state

private bool isDay = true;
// [ ... ]

isDay = !isDay;

daybg.SetActive(isDay);
nightbg.SetActive(!isDay);

This could even be packed into a property so when you set the IsDay property, you change the backgrounds accordingly

private bool m_IsDay;
public bool IsDay
{
    get => m_IsDay;
    set
    {
        m_IsDay = value;
        daybg.SetActive(m_IsDay);
        nightbg.SetActive(!m_IsDay);
    }
}

Now you can simply do

IsDay = !IsDay;

to toggle the day / night state or set it to true / false explicitly and the backgrounds would change as well.

7

Thanks for the info. I’m glad there is more than one way to do things when programming. Code being flexible is nice.