Unity3D 编写游戏运行时间 格式为00:00:00

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

public class GameTime : MonoBehaviour {

// Use this for initialization

private Text text;

private float timer = 0f;

private int h = 0;

private int m = 0;

private int s = 0;

private string timeStr = string.Empty;
void Start()
{
text = GetComponent<Text>();
}

// Update is called once per frame
void Update()
{
timer += Time.deltaTime;
if (timer >= 1f)
{
s++;
timer = 0;
}
if (s >= 60)
{
m++;
s = 0;
}
if (m >= 60)
{
h++;
m = 0;
}
if (h >= 99)
{
h = 0;
}

timeStr = string.Format("{0:D2}:{1:D2}:{2:D2}", h, m, s);
text.text = "" + timeStr;
}
}