com.misaki.hdrp-toon/Runtime/BoxLightAdjustment.cs

using UnityEngine;
#if UNITY_EDITOR
using UnityEditor;
#endif

#if HDRP_IS_INSTALLED_FOR_UTS
using UnityEngine.Rendering.HighDefinition;
using Unity.Properties;

namespace Misaki.HdrpToon
{
    [ExecuteAlways]
    [DisallowMultipleComponent]
    [RequireComponent(typeof(Light))]
    public class BoxLightAdjustment : MonoBehaviour
    {
        private bool _initialized = false;
        private bool _srpCallbackInitialized = false;

        [SerializeField]
        private HDAdditionalLightData _bindingSourceLightData;
        [SerializeField]
        private HDAdditionalLightData _targetBoxLightData;

        [SerializeField]
        private uint _layerMask;
        [SerializeField]
        private Light _bindingSourceLight;
        [SerializeField]
        private Light _targetBoxLight;

        public Transform trackedTransform;
        public bool followGameObjectPosition = false;
        public float distanceOffset = 20.0f;

        [CreateProperty]
        public Light BindingSourceLight
        {
            get => _bindingSourceLight;
            set
            {
                _bindingSourceLight = value;
                _bindingSourceLightData = _bindingSourceLight.GetComponent<HDAdditionalLightData>();
            }
        }

        [CreateProperty]
        public Light TargetBoxLight
        {
            get => _targetBoxLight;
            set
            {
                _targetBoxLight = value;
                _targetBoxLightData = _targetBoxLight.GetComponent<HDAdditionalLightData>();
            }
        }

        [CreateProperty]
        public uint LayerMask
        {
            get => _layerMask;
            set
            {
                if (_targetBoxLight == null || _bindingSourceLight == null)
                {
                    return;
                }

                UpdateShadowLayer(_bindingSourceLightData, value);
                UpdateShadowLayer(_targetBoxLightData, value);

                _layerMask = value;
            }
        }

#if UNITY_EDITOR
#pragma warning restore CS0414
        private bool _isCompiling = false;
#endif

        private void Reset()
        {
            OnDisable();
            OnEnable();
        }

        internal void OnValidate()
        {
            Release();
            Initialize();
        }

        private void Awake()
        {
            Initialize();
        }

        // Update is called once per frame
        private void Update()
        {
            Initialize();

#if UNITY_EDITOR
            // handle script recompile
            if (EditorApplication.isCompiling && !_isCompiling)
            {
                // on compile begin
                _isCompiling = true;
                //                Release(); no need
                return; // 
            }
            else if (!EditorApplication.isCompiling && _isCompiling)
            {
                // on compile end
                _isCompiling = false;
            }
#endif
            if (_targetBoxLight == null || _bindingSourceLight == null)
            {
                return;
            }

            _targetBoxLight.enabled = _bindingSourceLight.enabled;
            _targetBoxLight.intensity = _bindingSourceLight.intensity;

            if (trackedTransform != null && followGameObjectPosition)
            {
                var desiredPosition = trackedTransform.position - _bindingSourceLight.transform.forward * distanceOffset;

                _targetBoxLight.transform.position = desiredPosition;
                _targetBoxLight.transform.rotation = _bindingSourceLight.transform.rotation;
            }
        }

        private void EnableSrpCallbacks()
        {

            if (!_srpCallbackInitialized)
            {
                _srpCallbackInitialized = true;
            }
        }

        private void DisableSrpCallbacks()
        {
            if (_srpCallbackInitialized)
            {
                _srpCallbackInitialized = false;
            }
        }

        private void OnEnable()
        {
            Initialize();

            EnableSrpCallbacks();
        }


        private void OnDisable()
        {
            DisableSrpCallbacks();

            Release();
        }

        internal static GameObject CreateBoxLight(Transform transform)
        {
            if (transform == null)
            {
                Debug.LogError("Please, select a GameObject you want a Box Light to follow.");
                return null;
            }
            var gameObjectName = "Box Light for " + transform.name;
            var lightGameObject = new GameObject(gameObjectName);
#if UNITY_EDITOR
            Undo.RegisterCreatedObjectUndo(lightGameObject, "Created Boxlight adjustment");
#endif
            var hdLightData = lightGameObject.AddHDLight(UnityEngine.LightType.Box);
            // light size
            hdLightData.SetBoxSpotSize(new Vector2(10.0f, 10.0f)); // Size should be culculated with more acculacy?
            var boxLightAdjustment = lightGameObject.GetComponent<BoxLightAdjustment>();
            if (boxLightAdjustment == null)
            {
#if UNITY_EDITOR
                boxLightAdjustment = Undo.AddComponent<BoxLightAdjustment>(lightGameObject);
#else
                boxLightAdjustment = lightGameObject.AddComponent<BoxLightAdjustment>();
#endif
            }



#if UNITY_EDITOR
            Undo.RecordObject(boxLightAdjustment, "target " + boxLightAdjustment.name);
#endif
            boxLightAdjustment._targetBoxLight = hdLightData.GetComponent<Light>();
#if UNITY_EDITOR
            Undo.RecordObject(lightGameObject.transform, "Position " + lightGameObject.transform.name);
#endif
            // position and rotation
            var goPos = lightGameObject.transform.position;
            goPos.y += 10.0f;
            lightGameObject.transform.position = goPos;

            var goRot = lightGameObject.transform.rotation;
            goRot.eulerAngles = new Vector3(90.0f, 0.0f, 0.0f);
#if UNITY_EDITOR
            Undo.RecordObject(lightGameObject.transform, "Rotation " + lightGameObject.transform.name);
#endif
            hdLightData.gameObject.transform.rotation = goRot;

            // must be put to gameObject model chain.
            boxLightAdjustment.trackedTransform = transform;


            return lightGameObject;
        }

        private void UpdateShadowLayer(HDAdditionalLightData lightData, uint newValue)
        {
            lightData.linkShadowLayers = false;
            var lightLayer = lightData.GetLightLayers();
            var newShadowLayer = lightLayer | newValue | UnityEngine.RenderingLayerMask.defaultRenderingLayerMask;
            lightData.SetShadowLightLayer((UnityEngine.Rendering.HighDefinition.RenderingLayerMask)newShadowLayer);
        }

        private void Initialize()
        {
            if (_initialized)
            {
                return;
            }
#if UNITY_EDITOR
            // initializing renderer can interfere GI baking. so wait until it is completed.

            if (EditorApplication.isCompiling)
                return;
#endif
            if (trackedTransform == null)
            {
                return;
            }

            if (_targetBoxLight != null)
            {
                distanceOffset = Mathf.Abs(Vector3.Distance(_targetBoxLight.transform.position, trackedTransform.transform.position));
            }

            _initialized = true;
        }

        private void Release()
        {
            _initialized = false;
        }
    }
}
#endif  // HDRP_IS_INSTALLED_FOR_UTS