Fix vlayering recompute per light option and make it a shader feature for easier testing.

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/StackLit/StackLitUI.cs

 
                 new GroupProperty(this, "_Debug", "Debug", new BaseProperty[]
                 {
+                    new Property(this, "_VlayerRecomputePerLight", "Vlayer Recompute Per Light", "", false),
                     new Property(this, "_DebugEnable", "Debug Enable", "Switch to a debug version of the shader", false),
                     new Property(this, "_DebugLobeMask", "DebugLobeMask", "xyz is Lobe 0 1 2 Enable, w is Enable VLayering", false),
                     new Property(this, "_DebugAniso", "DebugAniso", "x is Hack Enable, y is factor", false),
             // TEMP - Remove once dev is finish
             bool debugEnabled = material.HasProperty("_DebugEnable") && material.GetFloat("_DebugEnable") > 0.0f;
             CoreUtils.SetKeyword(material, "_STACKLIT_DEBUG", debugEnabled);
+
+            bool vlayerRecomputePerLight = material.HasProperty("_VlayerRecomputePerLight") && material.GetFloat("_VlayerRecomputePerLight") > 0.0f;
+            CoreUtils.SetKeyword(material, "_VLAYERED_RECOMPUTE_PERLIGHT", vlayerRecomputePerLight);
 
 
             // Set the reference value for the stencil test - required for SSS

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/StackLit/StackLit.hlsl

 
 // Vlayer config options:
 
-//#define VLAYERED_RECOMPUTE_PERLIGHT // TODO test more, make it a shader_features
+#ifdef _VLAYERED_RECOMPUTE_PERLIGHT
+#    define VLAYERED_RECOMPUTE_PERLIGHT 
+// Now a shader_features
+#endif
+
 //#define VLAYERED_USE_REFRACTED_ANGLES_FOR_BASE
 #define VLAYERED_DIFFUSE_ENERGY_HACKED_TERM
 //#define VLAYERED_ANISOTROPY_IBL_DESTRETCH
     }
 #endif
 
-    if( !perLightOption )
+    if( !perLightOption || calledPerLight)
     {
         ConvertAnisotropyToClampRoughness(preLightData.iblPerceptualRoughness[BASE_LOBEA_IDX], preLightData.iblAnisotropy[0],
                                           preLightData.layeredRoughnessT[0], preLightData.layeredRoughnessB[0]);

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/StackLit/StackLit.shader

         [HideInInspector] _SmoothnessBRange("SmoothnessB Range", Vector) = (0, 1, 0, 0)
         _LobeMix("Lobe Mix", Range(0.0, 1.0)) = 0
 
+        [ToggleUI] _VlayerRecomputePerLight("Vlayer Recompute Per Light", Float) = 0.0 // UI only
         [ToggleUI] _DebugEnable("Debug Enable", Float) = 0.0 // UI only
         _DebugLobeMask("DebugLobeMask", Vector) = (1, 1, 1, 1)
         _DebugAniso("DebugAniso", Vector) = (1, 0, 0, 1000.0)
     #pragma shader_feature _MATERIAL_FEATURE_IRIDESCENCE
     #pragma shader_feature _MATERIAL_FEATURE_SUBSURFACE_SCATTERING
     #pragma shader_feature _MATERIAL_FEATURE_TRANSMISSION
+
+    #pragma shader_feature _VLAYERED_RECOMPUTE_PERLIGHT
 
 
     #pragma shader_feature _STACKLIT_DEBUG