【Unity,C#】控制方向光模拟昼夜变化的脚本

效果

如何实现

• 创建TextPro用于实时显示时间

• 简单配置

• 创建空对象

• 加入脚本

• 脚本代码

using System;
using TMPro;
using UnityEngine;

public class TimeController : MonoBehaviour
{
    /// <summary>
    /// 显示24小时制时间
    /// </summary>
    [SerializeField]
    private TextMeshProUGUI txtTime;

    /// <summary>
    /// 定向光
    /// </summary>
    [SerializeField]
    private Light sunLight;

    /// <summary>
    /// 时间的增长步长
    /// </summary>
    [SerializeField]
    private float timeStep = 1000;

    /// <summary>
    /// 起始小时
    /// </summary>
    [SerializeField]
    private int startHour = 12;

    /// <summary>
    /// 日升小时
    /// </summary>
    [SerializeField]
    private int sunriseHour = 6;

    /// <summary>
    /// 日落小时
    /// </summary>
    [SerializeField]
    private int sunsetHour = 18;

    private DateTime currentTime;
    private TimeSpan sunriseTime;
    private TimeSpan sunsetTime;

    void Start()
    {
        currentTime = DateTime.Now.Date + TimeSpan.FromHours(startHour);
        sunriseTime = TimeSpan.FromHours(sunriseHour);
        sunsetTime = TimeSpan.FromHours(sunsetHour);
    }

    void Update()
    {
        updateTime();
        updateDirectionLight();
    }

    /// <summary>
    /// 更新光照角度
    /// </summary>
    private void updateDirectionLight()
    {
        float lightDegree = 0f;
        if (currentTime.TimeOfDay > sunriseTime && currentTime.TimeOfDay < sunsetTime)//白天
        {
            TimeSpan sunrise2SunsetInterval = getTimeInterval(sunriseTime, sunsetTime);
            TimeSpan sunrise2CurrentInterval = getTimeInterval(sunriseTime, currentTime.TimeOfDay);
            //算出比率:当前时间差和总时间
            double percentage = sunrise2CurrentInterval.TotalMilliseconds / sunrise2SunsetInterval.TotalMilliseconds;
            lightDegree = Mathf.Lerp(0, 180, (float)percentage);
        }
        else//夜晚
        {
            TimeSpan sunset2SunriseInterval = getTimeInterval(sunsetTime, sunriseTime);
            TimeSpan sunset2CurrentInterval = getTimeInterval(sunsetTime, currentTime.TimeOfDay);
            //算出比率:当前时间差和总时间
            double percentage = sunset2CurrentInterval.TotalMilliseconds / sunset2SunriseInterval.TotalMilliseconds;
            lightDegree = Mathf.Lerp(180, 360, (float)percentage);
        }

        //根据当前时间, 将表示日光的定向光旋转到对应的角度,围绕X轴旋转
        sunLight.transform.rotation = Quaternion.AngleAxis(lightDegree, Vector3.right);
    }

    /// <summary>
    /// 计算时间差
    /// </summary>
    /// <param name="firstTime"></param>
    /// <param name="secondTime"></param>
    /// <returns></returns>
    private TimeSpan getTimeInterval(TimeSpan firstTime, TimeSpan secondTime)
    {
        TimeSpan interval = secondTime - firstTime;
        if (interval.TotalSeconds < 0)
        {
            interval += TimeSpan.FromHours(24);
        }
        return interval;
    }

    /// <summary>
    /// 更新时间
    /// </summary>
    private void updateTime()
    {
        currentTime = currentTime.AddSeconds(Time.deltaTime * timeStep);
        if (txtTime != null)
        {
            txtTime.text = currentTime.ToString("HH:mm");
        }
    }


}