Light2D simple intensity tween

LightController.cs

#region MIT License
// # Released under MIT License
//
// Copyright (c) 2021 Byron Wright.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute,
// sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
// ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
#endregion


using System.Collections;
using UnityEngine;
using UnityEngine.Experimental.Rendering.Universal;

namespace RowdyRobot.Utils
{
  /// <summary>
  /// This behavior controls the intensity of a Light2D component using the defined parameters.
  /// </summary>
  [RequireComponent(typeof(Light2D))]
  public class LightController : MonoBehaviour
  {
    [SerializeField]
    private Light2D lightToControl;

    [Header("Controls")]
    [Tooltip("The starting intensity of the light to animate from.")]
    [SerializeField]
    private float fromIntensity;

    [Tooltip("The intensity you want the light to animate to.")]
    [SerializeField]
    private float toIntensity = 1.0f;

    [Tooltip("Defaults to linear. Values are relative to the from/to intensity.")]
    [SerializeField]
    private AnimationCurve lightIntensityAnimationCurve = new AnimationCurve
    (
      new Keyframe(0.0f, 0.0f),
      new Keyframe(1.0f, 1.0f)
    );

    [Tooltip("How long it should take for the light's intensity to reach \"toIntensity\".")]
    [SerializeField]
    private float animationDuration = 1.0f;

    [Tooltip("Should the animate play immediately. You will need to call \"StartAnimationIntensity()\" from script if disabled.")]
    [SerializeField]
    private bool startOnWake = true;

    private Coroutine _animationCoroutine;

    private void Awake()
    {
      if (lightToControl != null)
      {
        return;
      }

      // if a light hasn't been assigned through the editor we grab the one attached.
      lightToControl = GetComponent<Light2D>();
    }

    private void OnEnable()
    {
      if (startOnWake)
      {
        SwitchOn();
      }
    }

    public void SwitchOn()
    {
      // if called multiple times, reset it.
      StopIntensityAnimation();
      _animationCoroutine = StartCoroutine(AnimateIntensity());
    }

    public void SwitchOff()
    {
      StopIntensityAnimation();
      _animationCoroutine = StartCoroutine(ReverseIntensityAnimation());
    }
    /// <summary>
    /// Stop an already running animation.
    /// </summary>
    public void StopIntensityAnimation()
    {
      if (_animationCoroutine != null)
      {
        StopCoroutine(_animationCoroutine);
        _animationCoroutine = null;
      }
    }

    private IEnumerator ReverseIntensityAnimation()
    {
      var timeElapsed = animationDuration;
      var deltaIntensity = toIntensity - fromIntensity;
      while (timeElapsed > 0.0f)
      {
        var intensity =
          lightIntensityAnimationCurve.Evaluate(timeElapsed / animationDuration) * deltaIntensity +
          fromIntensity;
        lightToControl.intensity = intensity;
        timeElapsed -= Time.deltaTime;
        yield return null;
      }

      lightToControl.intensity = fromIntensity;
    }

    private IEnumerator AnimateIntensity()
    {
      var timeElapsed = 0.0f;
      var deltaIntensity = toIntensity - fromIntensity;
      while (timeElapsed < animationDuration)
      {
        var intensity =
          lightIntensityAnimationCurve.Evaluate(timeElapsed / animationDuration) * deltaIntensity +
          fromIntensity;
        lightToControl.intensity = intensity;
        timeElapsed += Time.deltaTime;
        yield return null;
      }

      lightToControl.intensity = toIntensity;
    }
  }
}