Simulating Day Night Cycle

using UnityEngine;

public class DayNightCycle : MonoBehaviour
{
    [Header("Time Settings")] [Range(0, 24)]
    public float timeOfDay = 12.0f;
    
    // seconds in real time for a full day cycle
    public float dayDuration = 240.0f; 

    [Header("Sun Settings")] public Light sun;

    public Gradient sunColor;
    public AnimationCurve sunIntensity;

    [Header("Sky Settings")] public Material skyboxMaterial;

    public float maxAmbientIntensity = 1.0f;
    public Gradient ambientColor;

    void Update()
    {
        // Update time of day
        timeOfDay += Time.deltaTime / dayDuration * 24.0f;
        if (timeOfDay >= 24.0f) {
            timeOfDay -= 24.0f;
        }

        // Calculate sun rotation
        // 15 degrees per hour, offset to start at dawn
        var sunRotation = timeOfDay * 15.0f - 90.0f;

        // Apply rotation to the sun
        sun.transform.rotation = Quaternion.Euler(sunRotation, -30.0f, 0);

        // Update light color and intensity based on time of day
        var dayNightRatio = Mathf.InverseLerp(0, 24, timeOfDay);
        if (timeOfDay > 12) {
            dayNightRatio = Mathf.InverseLerp(24, 12, timeOfDay);
        }

        sun.color = sunColor.Evaluate(dayNightRatio);
        sun.intensity = sunIntensity.Evaluate(dayNightRatio);

        // Update ambient lighting
        RenderSettings.ambientLight = ambientColor.Evaluate(dayNightRatio);

        // Update skybox (if using a skybox that supports time of day)
        if (skyboxMaterial != null && skyboxMaterial.HasProperty("_Exposure")) {
            skyboxMaterial.SetFloat("_Exposure", sunIntensity.Evaluate(dayNightRatio));
        }
    }
}

using UnityEngine;

public class DayNightCycle : MonoBehaviour
{
    [Header("Time Settings")] [Range(0, 24)]
    public float timeOfDay = 12.0f;
    
    // seconds in real time for a full day cycle
    public float dayDuration = 240.0f; 

    [Header("Sun Settings")] public Light sun;

    public Gradient sunColor;
    public AnimationCurve sunIntensity;

    [Header("Sky Settings")] public Material skyboxMaterial;

    public float maxAmbientIntensity = 1.0f;
    public Gradient ambientColor;

    void Update()
    {
        // Update time of day
        timeOfDay += Time.deltaTime / dayDuration * 24.0f;
        if (timeOfDay >= 24.0f) {
            timeOfDay -= 24.0f;
        }

        // Calculate sun rotation
        // 15 degrees per hour, offset to start at dawn
        var sunRotation = timeOfDay * 15.0f - 90.0f;

        // Apply rotation to the sun
        sun.transform.rotation = Quaternion.Euler(sunRotation, -30.0f, 0);

        // Update light color and intensity based on time of day
        var dayNightRatio = Mathf.InverseLerp(0, 24, timeOfDay);
        if (timeOfDay > 12) {
            dayNightRatio = Mathf.InverseLerp(24, 12, timeOfDay);
        }

        sun.color = sunColor.Evaluate(dayNightRatio);
        sun.intensity = sunIntensity.Evaluate(dayNightRatio);

        // Update ambient lighting
        RenderSettings.ambientLight = ambientColor.Evaluate(dayNightRatio);

        // Update skybox (if using a skybox that supports time of day)
        if (skyboxMaterial != null && skyboxMaterial.HasProperty("_Exposure")) {
            skyboxMaterial.SetFloat("_Exposure", sunIntensity.Evaluate(dayNightRatio));
        }
    }
}