unity3d之按秒倒计时

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

public class textTimer : MonoBehaviour
{
    // Start is called before the first frame update
    public int second = 120;
    private float startTime = 0;
    public Text mText;

    void Start()
    {
        mText = this.GetComponent<Text>();
        startTime = Time.time;
    }

    // Update is called once per frame
    void Update()
    {
        if ((Time.time - startTime) >= 1)
        {
            startTime = Time.time;
            second--;

            if (second <= 10) 
            {
                mText.color = Color.red;
            }
            mText.text = string.Format("{0:d2}:{1:d2}", second / 60, second % 60);
             
        }
    }
}