Remove 'bsdfData.roughness'

ScriptableRenderPipeline/Core/ShaderLibrary/CommonMaterial.hlsl

     return max(roughness, 1.0/1024.0);
 }
 
+// 'bsdfData.roughnessT' and 'bsdfData.roughnessB' are clamped, and are meant to be used with analytical lights.
+// 'bsdfData.perceptualRoughness' is not clamped, and is meant to be used for IBL.
+// If IBL needs the linear roughness value for some reason, it can be computed as follows:
+// float roughness = PerceptualRoughnessToRoughness(bsdfData.perceptualRoughness);
 void ConvertAnisotropyToRoughness(float perceptualRoughness, float anisotropy, out float roughnessT, out float roughnessB)
 {
     float roughness = PerceptualRoughnessToRoughness(perceptualRoughness);

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Lit.cs

             [SurfaceDataAttributes("", true)]
             public Vector3 normalWS;
             public float perceptualRoughness;
-            public float roughness;
             public int materialId;
 
             // MaterialId dependent attribute

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Lit.cs.hlsl

 #define DEBUGVIEW_LIT_BSDFDATA_SPECULAR_OCCLUSION (1032)
 #define DEBUGVIEW_LIT_BSDFDATA_NORMAL_WS (1033)
 #define DEBUGVIEW_LIT_BSDFDATA_PERCEPTUAL_ROUGHNESS (1034)
-#define DEBUGVIEW_LIT_BSDFDATA_ROUGHNESS (1035)
-#define DEBUGVIEW_LIT_BSDFDATA_MATERIAL_ID (1036)
-#define DEBUGVIEW_LIT_BSDFDATA_TANGENT_WS (1037)
-#define DEBUGVIEW_LIT_BSDFDATA_BITANGENT_WS (1038)
-#define DEBUGVIEW_LIT_BSDFDATA_ROUGHNESS_T (1039)
-#define DEBUGVIEW_LIT_BSDFDATA_ROUGHNESS_B (1040)
-#define DEBUGVIEW_LIT_BSDFDATA_ANISOTROPY (1041)
-#define DEBUGVIEW_LIT_BSDFDATA_SUBSURFACE_RADIUS (1042)
-#define DEBUGVIEW_LIT_BSDFDATA_THICKNESS (1043)
-#define DEBUGVIEW_LIT_BSDFDATA_SUBSURFACE_PROFILE (1044)
-#define DEBUGVIEW_LIT_BSDFDATA_ENABLE_TRANSMISSION (1045)
-#define DEBUGVIEW_LIT_BSDFDATA_USE_THIN_OBJECT_MODE (1046)
-#define DEBUGVIEW_LIT_BSDFDATA_TRANSMITTANCE (1047)
-#define DEBUGVIEW_LIT_BSDFDATA_COAT_NORMAL_WS (1048)
-#define DEBUGVIEW_LIT_BSDFDATA_COAT_COVERAGE (1049)
-#define DEBUGVIEW_LIT_BSDFDATA_COAT_IOR (1050)
-#define DEBUGVIEW_LIT_BSDFDATA_IOR (1051)
-#define DEBUGVIEW_LIT_BSDFDATA_ABSORPTION_COEFFICIENT (1052)
-#define DEBUGVIEW_LIT_BSDFDATA_TRANSMITTANCE_MASK (1053)
+#define DEBUGVIEW_LIT_BSDFDATA_MATERIAL_ID (1035)
+#define DEBUGVIEW_LIT_BSDFDATA_TANGENT_WS (1036)
+#define DEBUGVIEW_LIT_BSDFDATA_BITANGENT_WS (1037)
+#define DEBUGVIEW_LIT_BSDFDATA_ROUGHNESS_T (1038)
+#define DEBUGVIEW_LIT_BSDFDATA_ROUGHNESS_B (1039)
+#define DEBUGVIEW_LIT_BSDFDATA_ANISOTROPY (1040)
+#define DEBUGVIEW_LIT_BSDFDATA_SUBSURFACE_RADIUS (1041)
+#define DEBUGVIEW_LIT_BSDFDATA_THICKNESS (1042)
+#define DEBUGVIEW_LIT_BSDFDATA_SUBSURFACE_PROFILE (1043)
+#define DEBUGVIEW_LIT_BSDFDATA_ENABLE_TRANSMISSION (1044)
+#define DEBUGVIEW_LIT_BSDFDATA_USE_THIN_OBJECT_MODE (1045)
+#define DEBUGVIEW_LIT_BSDFDATA_TRANSMITTANCE (1046)
+#define DEBUGVIEW_LIT_BSDFDATA_COAT_NORMAL_WS (1047)
+#define DEBUGVIEW_LIT_BSDFDATA_COAT_COVERAGE (1048)
+#define DEBUGVIEW_LIT_BSDFDATA_COAT_IOR (1049)
+#define DEBUGVIEW_LIT_BSDFDATA_IOR (1050)
+#define DEBUGVIEW_LIT_BSDFDATA_ABSORPTION_COEFFICIENT (1051)
+#define DEBUGVIEW_LIT_BSDFDATA_TRANSMITTANCE_MASK (1052)
 
 //
 // UnityEngine.Experimental.Rendering.HDPipeline.Lit+GBufferMaterial:  static fields
     float specularOcclusion;
     float3 normalWS;
     float perceptualRoughness;
-    float roughness;
     int materialId;
     float3 tangentWS;
     float3 bitangentWS;
             break;
         case DEBUGVIEW_LIT_BSDFDATA_PERCEPTUAL_ROUGHNESS:
             result = bsdfdata.perceptualRoughness.xxx;
-            break;
-        case DEBUGVIEW_LIT_BSDFDATA_ROUGHNESS:
-            result = bsdfdata.roughness.xxx;
             break;
         case DEBUGVIEW_LIT_BSDFDATA_MATERIAL_ID:
             result = GetIndexColor(bsdfdata.materialId);

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Lit.hlsl

     bsdfData.anisotropy          = surfaceData.anisotropy;
     bsdfData.perceptualRoughness = PerceptualSmoothnessToPerceptualRoughness(surfaceData.perceptualSmoothness);
 
-    // Warning: 'bsdfData.roughness' is not meant to be used. Otherwise, we increase the register pressure.
-    // 'bsdfData.roughnessT' and 'bsdfData.roughnessB' are clamped, and are meant to be used with analytical lights.
-    // 'bsdfData.perceptualRoughness' is not clamped, and is meant to be used for IBL.
-    // If IBL needs the linear roughness value for some reason, it can be computed as follows:
-    // float roughness = PerceptualRoughnessToRoughness(bsdfData.perceptualRoughness);
-    bsdfData.roughness = FLT_NAN;
-
     ConvertAnisotropyToRoughness(bsdfData.perceptualRoughness, bsdfData.anisotropy, bsdfData.roughnessT, bsdfData.roughnessB);
 
     if (surfaceData.materialId != MATERIALID_LIT_ANISO)
 
         bsdfData.bitangentWS = cross(bsdfData.normalWS, bsdfData.tangentWS);
     }
-
-    // Warning: 'bsdfData.roughness' is not meant to be used. Otherwise, we increase the register pressure.
-    // 'bsdfData.roughnessT' and 'bsdfData.roughnessB' are clamped, and are meant to be used with analytical lights.
-    // 'bsdfData.perceptualRoughness' is not clamped, and is meant to be used for IBL.
-    // If IBL needs the linear roughness value for some reason, it can be computed as follows:
-    // float roughness = PerceptualRoughnessToRoughness(bsdfData.perceptualRoughness);
-    // TODO: remove 'bsdfData.roughness' completely.
-    bsdfData.roughness = FLT_NAN;
 
     ConvertAnisotropyToRoughness(bsdfData.perceptualRoughness, bsdfData.anisotropy, bsdfData.roughnessT, bsdfData.roughnessB);