Added custom light data shadow and light layer sync with the main light.

Fixes - Setting shadow rendering layer is not changing shadow when using “shadowRenderingLayers” in the script
https://jira.unity3d.com/browse/UUM-28061

Added logic similar to UI. Where we replace base light component renderingLayerMask with either shadow or light layers. Which later used for shadow drawing.

Author: alekseiunity

Packages/com.unity.render-pipelines.universal/Runtime/UniversalAdditionalLightData.cs

@@ -108,6 +108,25 @@ public bool usePipelineSettings
         /// </summary>
         public static readonly int AdditionalLightsShadowDefaultCustomResolution = 128;
 
+        [NonSerialized] private Light m_Light;
+
+        /// <summary>
+        /// Returns the cached light component associated with the game object that owns this light data.
+        /// </summary>
+#if UNITY_EDITOR
+        internal new Light light
+#else
+        internal Light light
+#endif
+        {
+            get
+            {
+                if (!m_Light)
+                    TryGetComponent(out m_Light);
+                return m_Light;
+            }
+        }
+
         /// <summary>
         /// The minimum shadow resolution for additional lights.
         /// </summary>
@@ -146,8 +165,18 @@ public LightLayerEnum lightLayerMask
         /// </summary>
         public uint renderingLayers
         {
-            get { return m_RenderingLayers; }
-            set { m_RenderingLayers = value; }
+            get
+            {
+                return m_RenderingLayers;
+            }
+            set
+            {
+                if (m_RenderingLayers != value)
+                {
+                    m_RenderingLayers = value;
+                    SyncLightAndShadowLayers();
+                }
+            }
         }
 
         [SerializeField] bool m_CustomShadowLayers = false;
@@ -158,8 +187,18 @@ public uint renderingLayers
         /// </summary>
         public bool customShadowLayers
         {
-            get { return m_CustomShadowLayers; }
-            set { m_CustomShadowLayers = value; }
+            get
+            {
+                return m_CustomShadowLayers;
+            }
+            set
+            {
+                if (m_CustomShadowLayers != value)
+                {
+                    m_CustomShadowLayers = value;
+                    SyncLightAndShadowLayers();
+                }
+            }
         }
 
         // The layer(s) used for shadow casting.
@@ -181,8 +220,18 @@ public LightLayerEnum shadowLayerMask
         /// </summary>
         public uint shadowRenderingLayers
         {
-            get { return m_ShadowRenderingLayers; }
-            set { m_ShadowRenderingLayers = value; }
+            get
+            {
+                return m_ShadowRenderingLayers;
+            }
+            set
+            {
+                if (value != m_ShadowRenderingLayers)
+                {
+                    m_ShadowRenderingLayers = value;
+                    SyncLightAndShadowLayers();
+                }
+            }
         }
 
         /// <summary>
@@ -242,5 +291,11 @@ public void OnAfterDeserialize()
                 m_Version = 3;
             }
         }
+
+        private void SyncLightAndShadowLayers()
+        {
+            if (light)
+                light.renderingLayerMask = m_CustomShadowLayers ? (int)m_ShadowRenderingLayers : (int)m_RenderingLayers;
+        }
     }
 }

Packages/com.unity.render-pipelines.universal/Tests/Runtime/LightTests.cs

@@ -0,0 +1,37 @@
+using NUnit.Framework;
+
+namespace UnityEngine.Rendering.Universal.Tests
+{
+    [TestFixture]
+    class LightTests
+    {
+        [Test]
+        public void TestMainLightRenderingLayerMaskSyncWithUniversalLightAndShadowLayers()
+        {
+            var lightObject = new GameObject("Light");
+            var light = lightObject.AddComponent<Light>();
+            var lightData = light.GetUniversalAdditionalLightData();
+
+            lightData.renderingLayers = (1 << 1);
+            lightData.shadowRenderingLayers = (1 << 2);
+
+            lightData.customShadowLayers = false;
+            Assert.AreEqual(light.renderingLayerMask, lightData.renderingLayers);
+
+            lightData.customShadowLayers = true;
+            Assert.AreEqual(light.renderingLayerMask, lightData.shadowRenderingLayers);
+
+            lightData.customShadowLayers = false;
+            lightData.renderingLayers = (1 << 3);
+            lightData.shadowRenderingLayers = (1 << 4);
+            Assert.AreEqual(light.renderingLayerMask, lightData.renderingLayers);
+
+            lightData.customShadowLayers = true;
+            lightData.renderingLayers = (1 << 5);
+            lightData.shadowRenderingLayers = (1 << 6);
+            Assert.AreEqual(light.renderingLayerMask, lightData.shadowRenderingLayers);
+
+            Object.DestroyImmediate(lightObject);
+        }
+    }
+}