Unity Simple Light Flicker

SimpleLightFlicker.cs

// Aaron Trotter aarontrotter.co.uk 2019
// Free to use and modify.
// Do give credit where credit due.

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

public class SimpleLightFlicker : MonoBehaviour
{

    public float flickerContinuousSpeed = 1f;
    private Light lightComponent = null;
    public float flickerContinuousMaxIntensity = 0.4f;
    public float flickerContinuousMinIntensity = 0.2f;
    public bool fadeOut = false;

    private bool isFlickering = false;
    private bool isFadingOut = false;
    private bool isFadingIn = false;

    private bool doOnce = false;

    private void OnEnable()
    {
        if (!doOnce)
        {
            lightComponent = GetComponent<Light>();
            doOnce = true;
        }

        lightComponent.intensity = flickerContinuousMaxIntensity;
    }


    public void Update()
    {
        if (fadeOut)
        {
            if (!isFadingOut)
            {
                if (lightComponent.intensity != 0)
                {
                    StopAllCoroutines();
                    isFadingOut = true;
                    isFadingIn = false;
                    isFlickering = false;
                    StartCoroutine(FadeLight(lightComponent, lightComponent.intensity, 0, 1f));
                }
            }
        }
        else
        {
            if (lightComponent.intensity >= 0 && lightComponent.intensity < flickerContinuousMinIntensity)
            {
                if (!isFadingIn)
                {
                    StopAllCoroutines();
                    isFadingOut = false;
                    isFadingIn = true;
                    isFlickering = false;
                    StartCoroutine(FadeLight(lightComponent, lightComponent.intensity, flickerContinuousMaxIntensity, 1f));
                }
            }
            else
            {
                if (!isFlickering)
                {
                    StopAllCoroutines();
                    isFadingOut = false;
                    isFadingIn = false;
                    isFlickering = true;
                    if (lightComponent.intensity == flickerContinuousMaxIntensity)
                    {
                        StartCoroutine(FadeLight(lightComponent, lightComponent.intensity, flickerContinuousMinIntensity, flickerContinuousSpeed));
                    }
                    else
                    {
                        StartCoroutine(FadeLight(lightComponent, lightComponent.intensity, flickerContinuousMaxIntensity, flickerContinuousSpeed));
                    }
                }
            }
        }
    }

    public IEnumerator FadeLight(Light light, float from, float to, float time)
    {
        float startTime = Time.time;
        float timeElapsed = 0;
        float journeyLength = from > to ? from - to : to - from;
        float fracJourney;

        float step = 0.0f;

        if (from != to)
        {

            for (float i = 0.0f; i < time; i = fracJourney)
            {
                timeElapsed = (Time.time - startTime);
                fracJourney = (timeElapsed / journeyLength);

                step = fracJourney / time;
                float val = Mathf.Lerp(from, to, step);

                light.intensity = val;

                yield return null;
            }
        }
        yield return null;

        light.intensity = to;

        if (isFlickering)
        {
            if (to == flickerContinuousMaxIntensity)
            {
                StartCoroutine(FadeLight(lightComponent, lightComponent.intensity, flickerContinuousMinIntensity, flickerContinuousSpeed));
            }
            else
            {
                StartCoroutine(FadeLight(lightComponent, lightComponent.intensity, flickerContinuousMaxIntensity, flickerContinuousSpeed));
            }
        }
        else if (isFadingOut)
        {
            isFadingOut = false;
        }

        yield return null;
    }
}