时钟计时和倒计时

效果图如下：

`using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;


public class TimeTest : MonoBehaviour
{
    public Text timeCountAddText;
    public Text timeCountDownText;
    public float timeDown = 10000;

    private float timeAdd = 0;

    private void FixedUpdate()
    {
        TimeAdd();
        TimeDown();
    }

    private void TimeAdd()
    {
        timeAdd += Time.fixedDeltaTime;
        int minute = Mathf.FloorToInt(timeAdd / 60f);
        if (minute < 10)
        {
            timeCountAddText.text = "0" + minute;
        }
        else
        {
            timeCountAddText.text = minute.ToString();
        }
        int second = Mathf.FloorToInt(timeAdd % 60f);
        timeCountAddText.text += ":" + second;
    }

    private void TimeDown()
    {
        if(timeDown>=0)
        {
            timeDown -= Time.fixedDeltaTime;
            int hour = Mathf.FloorToInt(timeDown / 3600f);
            if(hour<10)
            {
                timeCountDownText.text = "0" + hour;
            }
            else 
            {
                timeCountDownText.text = "" + hour; 
            }

            int minute = Mathf.FloorToInt((timeDown % 3600) / 60f);
            if(minute<10)
            {
                timeCountDownText.text += ":0" + minute;
            }
            else 
            {
                timeCountDownText.text += ":" + minute;
            }
            int second = Mathf.FloorToInt(timeDown % 60f);
            if (second < 10)
            {
                timeCountDownText.text += ":0" + second;
            }
            else
            {
                timeCountDownText.text += ":" + second;
            }
        }
        else 
        {
            timeCountDownText.text = "00:00:00";
        }


    }

}`