Use the stencil to avoid shading empty parts of the G-buffer

Assets/ScriptableRenderLoop/HDRenderPipeline/Lighting/Resources/Deferred.shader

 
                 PreLightData preLightData = GetPreLightData(V, posInput, bsdfData);
 
-                float3 diffuseLighting  = float3(0, 0, 0);
-                float3 specularLighting = float3(0, 0, 0);
-
-            #if UNITY_REVERSED_Z
-                float clearDepth = 0;
-            #else
-                float clearDepth = 1;
-            #endif
-
-                // Do not shade the far plane - wastes cycles and produces wrong results.
-                if (depth != clearDepth)
-                {
-                    LightLoop(V, posInput, preLightData, bsdfData, bakeDiffuseLighting, diffuseLighting, specularLighting);
-                }
+                float3 diffuseLighting;
+                float3 specularLighting;
+                LightLoop(V, posInput, preLightData, bsdfData, bakeDiffuseLighting, diffuseLighting, specularLighting);
 
                 Outputs outputs;
             #ifdef OUTPUT_SPLIT_LIGHTING

Assets/ScriptableRenderLoop/HDRenderPipeline/Lighting/TilePass/TilePass.cs

                 Utilities.SelectKeyword(m_DeferredDirectMaterialSRT, tileKeywords, 0);
                 m_DeferredDirectMaterialSRT.EnableKeyword("LIGHTLOOP_TILE_PASS");
                 m_DeferredDirectMaterialSRT.DisableKeyword("OUTPUT_SPLIT_LIGHTING");
-                m_DeferredDirectMaterialSRT.SetInt("_StencilRef", (int)StencilBits.None);
+                m_DeferredDirectMaterialSRT.SetInt("_StencilRef", (int)StencilBits.Standard);
                 m_DeferredDirectMaterialSRT.SetInt("_SrcBlend", (int)BlendMode.One);
                 m_DeferredDirectMaterialSRT.SetInt("_DstBlend", (int)BlendMode.Zero);
 
                 Utilities.SelectKeyword(m_DeferredIndirectMaterialSRT, tileKeywords, 1);
                 m_DeferredIndirectMaterialSRT.EnableKeyword("LIGHTLOOP_TILE_PASS");
                 m_DeferredIndirectMaterialSRT.DisableKeyword("OUTPUT_SPLIT_LIGHTING");
-                m_DeferredIndirectMaterialSRT.SetInt("_StencilRef", (int)StencilBits.None);
+                m_DeferredIndirectMaterialSRT.SetInt("_StencilRef", (int)StencilBits.Standard);
                 m_DeferredIndirectMaterialSRT.SetInt("_SrcBlend", (int)BlendMode.One);
                 m_DeferredIndirectMaterialSRT.SetInt("_DstBlend", (int)BlendMode.One); // Additive color & alpha source
 
                 Utilities.SelectKeyword(m_DeferredAllMaterialSRT, tileKeywords, 2);
                 m_DeferredAllMaterialSRT.EnableKeyword("LIGHTLOOP_TILE_PASS");
                 m_DeferredAllMaterialSRT.DisableKeyword("OUTPUT_SPLIT_LIGHTING");
-                m_DeferredAllMaterialSRT.SetInt("_StencilRef", (int)StencilBits.None);
+                m_DeferredAllMaterialSRT.SetInt("_StencilRef", (int)StencilBits.Standard);
                 m_DeferredAllMaterialSRT.SetInt("_SrcBlend", (int)BlendMode.One);
                 m_DeferredAllMaterialSRT.SetInt("_DstBlend", (int)BlendMode.Zero);
 
                 m_SingleDeferredMaterialSRT = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
                 m_SingleDeferredMaterialSRT.EnableKeyword("LIGHTLOOP_SINGLE_PASS");
                 m_SingleDeferredMaterialSRT.DisableKeyword("OUTPUT_SPLIT_LIGHTING");
-                m_SingleDeferredMaterialSRT.SetInt("_StencilRef", (int)StencilBits.None);
+                m_SingleDeferredMaterialSRT.SetInt("_StencilRef", (int)StencilBits.Standard);
                 m_SingleDeferredMaterialSRT.SetInt("_SrcBlend", (int)BlendMode.One);
                 m_SingleDeferredMaterialSRT.SetInt("_DstBlend", (int)BlendMode.Zero);
 

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Editor/LitUI.cs

                 material.DisableKeyword("_REQUIRE_UV3");
             }
 
-            material.SetInt("_StencilRef", (int)material.GetFloat(kMaterialID)); // See 'StencilBits'.
+            material.SetInt("_StencilRef", 1 + (int)material.GetFloat(kMaterialID)); // See 'StencilBits'.
          }
     }
 } // namespace UnityEditor

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Resources/CombineSubsurfaceScattering.shader

         {
             Stencil
             {
-                Ref  1 // StencilBits.SSS
+                Ref  2 // StencilBits.SSS
                 Comp Equal
                 Pass Keep
             }

Assets/ScriptableRenderLoop/HDRenderPipeline/Utilities.cs

     [Flags]
     public enum StencilBits
     {
-        None      = Lit.MaterialId.LitStandard, 
-        SSS       = Lit.MaterialId.LitSSS,
-        ClearCoat = Lit.MaterialId.LitClearCoat,
+        None      = 0,
+        Standard  = 1 + Lit.MaterialId.LitStandard,
+        SSS       = 1 + Lit.MaterialId.LitSSS,
+        ClearCoat = 1 + Lit.MaterialId.LitClearCoat,
         All       = 255 // 0xff
     }