ScriptableRenderPipeline/com.unity.render-pipelines.high-definition/HDRP/Editor/ShaderGraph/HDPBRPass.template

Pass
{
    // based on HDPBRPass.template
    Name "${PassName}"
    Tags { "LightMode" = "${LightMode}" }

    //-------------------------------------------------------------------------------------
    // Render Modes (Blend, Cull, ZTest, Stencil, etc)
    //-------------------------------------------------------------------------------------
        ${Blending}
        ${Culling}
        ${ZTest}
        ${ZWrite}
        ${Stencil}
        ${ColorMask}
    //-------------------------------------------------------------------------------------
    // End Render Modes
    //-------------------------------------------------------------------------------------

    HLSLPROGRAM

    #pragma target 4.5
    #pragma only_renderers d3d11 ps4 xboxone vulkan metal switch
    //#pragma enable_d3d11_debug_symbols

    //-------------------------------------------------------------------------------------
    // Variant Definitions (active field translations to HDRP defines)
    //-------------------------------------------------------------------------------------
        $AlphaTest:                      #define _ALPHATEST_ON 1
        $Material.SubsurfaceScattering:  #define _MATERIAL_FEATURE_SUBSURFACE_SCATTERING 1
        $Material.Transmission:          #define _MATERIAL_FEATURE_TRANSMISSION 1
        $Material.Anisotropy:            #define _MATERIAL_FEATURE_ANISOTROPY 1
        $Material.ClearCoat:             #define _MATERIAL_FEATURE_CLEAR_COAT 1
        $Material.Iridescence:           #define _MATERIAL_FEATURE_IRIDESCENCE 1
        $Material.SpecularColor:         #define _MATERIAL_FEATURE_SPECULAR_COLOR 1
        $SurfaceType.Transparent:        #define _SURFACE_TYPE_TRANSPARENT 1
        $BlendMode.Alpha:                #define _BLENDMODE_ALPHA 1
        $BlendMode.Add:                  #define _BLENDMODE_ADD 1
    //-------------------------------------------------------------------------------------
    // End Variant Definitions
    //-------------------------------------------------------------------------------------

    #pragma vertex Vert
    #pragma fragment Frag

    #define UNITY_MATERIAL_LIT      // Need to be define before including Material.hlsl

    // Use surface gradient normal mapping as it handle correctly triplanar normal mapping and multiple UVSet
    // this modifies the normal calculation
    // #define SURFACE_GRADIENT

    // If we use subsurface scattering, enable output split lighting (for forward pass)
    #if defined(_MATID_SSS) && !defined(_SURFACE_TYPE_TRANSPARENT)
    #define OUTPUT_SPLIT_LIGHTING
    #endif

    #include "CoreRP/ShaderLibrary/Common.hlsl"
    #include "CoreRP/ShaderLibrary/Wind.hlsl"

    #include "CoreRP/ShaderLibrary/NormalSurfaceGradient.hlsl"

    #include "ShaderGraphLibrary/Functions.hlsl"

    // define FragInputs structure
    #include "HDRP/ShaderPass/FragInputs.hlsl"
    #include "HDRP/ShaderPass/ShaderPass.cs.hlsl"

    //-------------------------------------------------------------------------------------
    // Defines
    //-------------------------------------------------------------------------------------
${Defines}

        // this translates the new dependency tracker into the old preprocessor definitions for the existing HDRP shader code
        $AttributesMesh.normalOS:               #define ATTRIBUTES_NEED_NORMAL
        $AttributesMesh.tangentOS:              #define ATTRIBUTES_NEED_TANGENT
        $AttributesMesh.uv0:                    #define ATTRIBUTES_NEED_TEXCOORD0
        $AttributesMesh.uv1:                    #define ATTRIBUTES_NEED_TEXCOORD1
        $AttributesMesh.uv2:                    #define ATTRIBUTES_NEED_TEXCOORD2
        $AttributesMesh.uv3:                    #define ATTRIBUTES_NEED_TEXCOORD3
        $AttributesMesh.color:                  #define ATTRIBUTES_NEED_COLOR
        $VaryingsMeshToPS.positionRWS:          #define VARYINGS_NEED_POSITION_WS
        $VaryingsMeshToPS.normalWS:             #define VARYINGS_NEED_TANGENT_TO_WORLD
        $VaryingsMeshToPS.texCoord0:            #define VARYINGS_NEED_TEXCOORD0
        $VaryingsMeshToPS.texCoord1:            #define VARYINGS_NEED_TEXCOORD1
        $VaryingsMeshToPS.texCoord2:            #define VARYINGS_NEED_TEXCOORD2
        $VaryingsMeshToPS.texCoord3:            #define VARYINGS_NEED_TEXCOORD3
        $VaryingsMeshToPS.color:                #define VARYINGS_NEED_COLOR
        $VaryingsMeshToPS.cullFace:             #define VARYINGS_NEED_CULLFACE
        $features.modifyMesh:                   #define HAVE_MESH_MODIFICATION

    //-------------------------------------------------------------------------------------
    // End Defines
    //-------------------------------------------------------------------------------------

    #include "ShaderGraphLibrary/Functions.hlsl"
    #include "HDRP/ShaderVariables.hlsl"
    #ifdef DEBUG_DISPLAY
        #include "HDRP/Debug/DebugDisplay.hlsl"
    #endif

    #if (SHADERPASS == SHADERPASS_FORWARD)
        // used for shaders that want to do lighting (and materials)
        #include "HDRP/Lighting/Lighting.hlsl"
    #else
        // used for shaders that don't need lighting
        #include "HDRP/Material/Material.hlsl"
    #endif
    #include "HDRP/Material/MaterialUtilities.hlsl"

    // this function assumes the bitangent flip is encoded in tangentWS.w
    // TODO: move this function to HDRP shared file, once we merge with HDRP repo
    float3x3 BuildWorldToTangent(float4 tangentWS, float3 normalWS)
    {
        // tangentWS must not be normalized (mikkts requirement)

        // Normalize normalWS vector but keep the renormFactor to apply it to bitangent and tangent
	    float3 unnormalizedNormalWS = normalWS;
        float renormFactor = 1.0 / length(unnormalizedNormalWS);

        // bitangent on the fly option in xnormal to reduce vertex shader outputs.
	    // this is the mikktspace transformation (must use unnormalized attributes)
        float3x3 worldToTangent = CreateWorldToTangent(unnormalizedNormalWS, tangentWS.xyz, tangentWS.w > 0.0 ? 1.0 : -1.0);

	    // surface gradient based formulation requires a unit length initial normal. We can maintain compliance with mikkts
	    // by uniformly scaling all 3 vectors since normalization of the perturbed normal will cancel it.
        worldToTangent[0] = worldToTangent[0] * renormFactor;
        worldToTangent[1] = worldToTangent[1] * renormFactor;
        worldToTangent[2] = worldToTangent[2] * renormFactor;		// normalizes the interpolated vertex normal
        return worldToTangent;
    }

    //-------------------------------------------------------------------------------------
    // Interpolator Packing And Struct Declarations
    //-------------------------------------------------------------------------------------
${InterpolatorPacking}
    //-------------------------------------------------------------------------------------
    // End Interpolator Packing And Struct Declarations
    //-------------------------------------------------------------------------------------

    //-------------------------------------------------------------------------------------
    // Graph generated code
    //-------------------------------------------------------------------------------------
${Graph}
    //-------------------------------------------------------------------------------------
    // End graph generated code
    //-------------------------------------------------------------------------------------

#ifdef HAVE_MESH_MODIFICATION
        // TODO: we should share this between template files somehow
        VertexDescriptionInputs AttributesMeshToVertexDescriptionInputs(AttributesMesh input)
        {
            VertexDescriptionInputs output;
            ZERO_INITIALIZE(VertexDescriptionInputs, output);

            $VertexDescriptionInputs.ObjectSpaceNormal:         output.ObjectSpaceNormal =           input.normalOS;
            $VertexDescriptionInputs.WorldSpaceNormal:          output.WorldSpaceNormal =            TransformObjectToWorldNormal(input.normalOS);
            $VertexDescriptionInputs.ViewSpaceNormal:           output.ViewSpaceNormal =             TransformWorldToViewDir(output.WorldSpaceNormal);
            $VertexDescriptionInputs.TangentSpaceNormal:        output.TangentSpaceNormal =          float3(0.0f, 0.0f, 1.0f);
            $VertexDescriptionInputs.ObjectSpaceTangent:        output.ObjectSpaceTangent =          input.tangentOS;
            $VertexDescriptionInputs.WorldSpaceTangent:		    output.WorldSpaceTangent =           TransformObjectToWorldDir(input.tangentOS.xyz);
            $VertexDescriptionInputs.ViewSpaceTangent:          output.ViewSpaceTangent =            TransformWorldToViewDir(output.WorldSpaceTangent);
            $VertexDescriptionInputs.TangentSpaceTangent:       output.TangentSpaceTangent =         float3(1.0f, 0.0f, 0.0f);
            $VertexDescriptionInputs.ObjectSpaceBiTangent:      output.ObjectSpaceBiTangent =        normalize(cross(input.normalOS, input.tangentOS) * (input.tangentOS.w > 0.0f ? 1.0f : -1.0f) * GetOddNegativeScale());
            $VertexDescriptionInputs.WorldSpaceBiTangent:       output.WorldSpaceBiTangent =         TransformObjectToWorldDir(output.ObjectSpaceBiTangent);
            $VertexDescriptionInputs.ViewSpaceBiTangent:        output.ViewSpaceBiTangent =          TransformWorldToViewDir(output.WorldSpaceBiTangent);
            $VertexDescriptionInputs.TangentSpaceBiTangent:     output.TangentSpaceBiTangent =       float3(0.0f, 1.0f, 0.0f);
            $VertexDescriptionInputs.ObjectSpacePosition:       output.ObjectSpacePosition =         input.positionOS;
            $VertexDescriptionInputs.WorldSpacePosition:        output.WorldSpacePosition =          GetAbsolutePositionWS(TransformObjectToWorld(input.positionOS));
            $VertexDescriptionInputs.ViewSpacePosition:         output.ViewSpacePosition =           TransformWorldToView(output.WorldSpacePosition);
            $VertexDescriptionInputs.TangentSpacePosition:      output.TangentSpacePosition =        float3(0.0f, 0.0f, 0.0f);
            $VertexDescriptionInputs.WorldSpaceViewDirection:   output.WorldSpaceViewDirection =     GetWorldSpaceNormalizeViewDir(output.WorldSpacePosition);
            $VertexDescriptionInputs.ObjectSpaceViewDirection:  output.ObjectSpaceViewDirection =    TransformWorldToObjectDir(output.WorldSpaceViewDirection);
            $VertexDescriptionInputs.ViewSpaceViewDirection:    output.ViewSpaceViewDirection =      TransformWorldToViewDir(output.WorldSpaceViewDirection);
            $VertexDescriptionInputs.TangentSpaceViewDirection: float3x3 tangentSpaceTransform =     float3x3(output.WorldSpaceTangent,output.WorldSpaceBiTangent,output.WorldSpaceNormal);
            $VertexDescriptionInputs.TangentSpaceViewDirection: output.TangentSpaceViewDirection =   mul(tangentSpaceTransform, output.WorldSpaceViewDirection);
            $VertexDescriptionInputs.ScreenPosition:            output.ScreenPosition =              ComputeScreenPos(TransformWorldToHClip(output.WorldSpacePosition), _ProjectionParams.x);
            $VertexDescriptionInputs.uv0:                       output.uv0 =                         float4(input.uv0, 0.0f, 0.0f);
            $VertexDescriptionInputs.uv1:                       output.uv1 =                         float4(input.uv1, 0.0f, 0.0f);
            $VertexDescriptionInputs.uv2:                       output.uv2 =                         float4(input.uv2, 0.0f, 0.0f);
            $VertexDescriptionInputs.uv3:                       output.uv3 =                         float4(input.uv3, 0.0f, 0.0f);
            $VertexDescriptionInputs.VertexColor:               output.VertexColor =                 input.color;

            return output;
        }

        AttributesMesh ApplyMeshModification(AttributesMesh input)
        {
            // build graph inputs
            VertexDescriptionInputs vertexDescriptionInputs = AttributesMeshToVertexDescriptionInputs(input);

            // evaluate vertex graph
            VertexDescription vertexDescription = VertexDescriptionFunction(vertexDescriptionInputs);

            // copy graph output to the results
            $VertexDescription.Position:    input.positionOS = vertexDescription.Position;

            return input;
        }
#endif // HAVE_MESH_MODIFICATION

	    // TODO: Do we want to build include functionality for sharing these preprocessed functions across templates?
        FragInputs BuildFragInputs(VaryingsMeshToPS input)
        {
            FragInputs output;
            ZERO_INITIALIZE(FragInputs, output);

            // Init to some default value to make the computer quiet (else it output 'divide by zero' warning even if value is not used).
            // TODO: this is a really poor workaround, but the variable is used in a bunch of places
            // to compute normals which are then passed on elsewhere to compute other values...
            output.worldToTangent = k_identity3x3;
            output.positionSS = input.positionCS;       // input.positionCS is SV_Position

            $FragInputs.positionRWS:        output.positionRWS = input.positionRWS;
            $FragInputs.worldToTangent:     output.worldToTangent = BuildWorldToTangent(input.tangentWS, input.normalWS);
            $FragInputs.texCoord0:          output.texCoord0 = input.texCoord0;
            $FragInputs.texCoord1:          output.texCoord1 = input.texCoord1;
            $FragInputs.texCoord2:          output.texCoord2 = input.texCoord2;
            $FragInputs.texCoord3:          output.texCoord3 = input.texCoord3;
            $FragInputs.color:              output.color = input.color;
            #if SHADER_STAGE_FRAGMENT
            $FragInputs.isFrontFace:        output.isFrontFace = IS_FRONT_VFACE(input.cullFace, true, false);       // TODO: SHADER_STAGE_FRAGMENT only
            $FragInputs.isFrontFace:        // Handle handness of the view matrix (In Unity view matrix default to a determinant of -1)
            $FragInputs.isFrontFace:        // when we render a cubemap the view matrix handness is flipped (due to convention used for cubemap) we have a determinant of +1
            $FragInputs.isFrontFace:        output.isFrontFace = _DetViewMatrix < 0.0 ? output.isFrontFace : !output.isFrontFace;
            #endif // SHADER_STAGE_FRAGMENT

            return output;
        }

        SurfaceDescriptionInputs FragInputsToSurfaceDescriptionInputs(FragInputs input, float3 viewWS)
        {
            SurfaceDescriptionInputs output;
            ZERO_INITIALIZE(SurfaceDescriptionInputs, output);

            $SurfaceDescriptionInputs.WorldSpaceNormal:          output.WorldSpaceNormal =            normalize(input.worldToTangent[2].xyz);
            $SurfaceDescriptionInputs.ObjectSpaceNormal:         output.ObjectSpaceNormal =           mul(output.WorldSpaceNormal, (float3x3) UNITY_MATRIX_M);      // transposed multiplication by inverse matrix to handle normal scale
            $SurfaceDescriptionInputs.ViewSpaceNormal:           output.ViewSpaceNormal =             mul(output.WorldSpaceNormal, (float3x3) UNITY_MATRIX_I_V);    // transposed multiplication by inverse matrix to handle normal scale
            $SurfaceDescriptionInputs.TangentSpaceNormal:        output.TangentSpaceNormal =          float3(0.0f, 0.0f, 1.0f);
            $SurfaceDescriptionInputs.WorldSpaceTangent:         output.WorldSpaceTangent =           input.worldToTangent[0].xyz;
            $SurfaceDescriptionInputs.ObjectSpaceTangent:        output.ObjectSpaceTangent =          TransformWorldToObjectDir(output.WorldSpaceTangent);
            $SurfaceDescriptionInputs.ViewSpaceTangent:          output.ViewSpaceTangent =            TransformWorldToViewDir(output.WorldSpaceTangent);
            $SurfaceDescriptionInputs.TangentSpaceTangent:       output.TangentSpaceTangent =         float3(1.0f, 0.0f, 0.0f);
            $SurfaceDescriptionInputs.WorldSpaceBiTangent:       output.WorldSpaceBiTangent =         input.worldToTangent[1].xyz;
            $SurfaceDescriptionInputs.ObjectSpaceBiTangent:      output.ObjectSpaceBiTangent =        TransformWorldToObjectDir(output.WorldSpaceBiTangent);
            $SurfaceDescriptionInputs.ViewSpaceBiTangent:        output.ViewSpaceBiTangent =          TransformWorldToViewDir(output.WorldSpaceBiTangent);
            $SurfaceDescriptionInputs.TangentSpaceBiTangent:     output.TangentSpaceBiTangent =       float3(0.0f, 1.0f, 0.0f);
            $SurfaceDescriptionInputs.WorldSpaceViewDirection:   output.WorldSpaceViewDirection =     normalize(viewWS);
            $SurfaceDescriptionInputs.ObjectSpaceViewDirection:  output.ObjectSpaceViewDirection =    TransformWorldToObjectDir(output.WorldSpaceViewDirection);
            $SurfaceDescriptionInputs.ViewSpaceViewDirection:    output.ViewSpaceViewDirection =      TransformWorldToViewDir(output.WorldSpaceViewDirection);
            $SurfaceDescriptionInputs.TangentSpaceViewDirection: float3x3 tangentSpaceTransform =     float3x3(output.WorldSpaceTangent,output.WorldSpaceBiTangent,output.WorldSpaceNormal);
            $SurfaceDescriptionInputs.TangentSpaceViewDirection: output.TangentSpaceViewDirection =   mul(tangentSpaceTransform, output.WorldSpaceViewDirection);
            $SurfaceDescriptionInputs.WorldSpacePosition:        output.WorldSpacePosition =          GetAbsolutePositionWS(input.positionRWS);
            $SurfaceDescriptionInputs.ObjectSpacePosition:       output.ObjectSpacePosition =         TransformWorldToObject(input.positionRWS);
            $SurfaceDescriptionInputs.ViewSpacePosition:         float4 posViewSpace =                TransformWorldToView(input.positionRWS);
            $SurfaceDescriptionInputs.ViewSpacePosition:         output.ViewSpacePosition =           posViewSpace.xyz / posViewSpace.w;
            $SurfaceDescriptionInputs.TangentSpacePosition:      output.TangentSpacePosition =        float3(0.0f, 0.0f, 0.0f);
            $SurfaceDescriptionInputs.ScreenPosition:            output.ScreenPosition =              ComputeScreenPos(TransformWorldToHClip(input.positionRWS), _ProjectionParams.x);
            $SurfaceDescriptionInputs.uv0:                       output.uv0 =                         float4(input.texCoord0, 0.0f, 0.0f);
            $SurfaceDescriptionInputs.uv1:                       output.uv1 =                         float4(input.texCoord1, 0.0f, 0.0f);
            $SurfaceDescriptionInputs.uv2:                       output.uv2 =                         float4(input.texCoord2, 0.0f, 0.0f);
            $SurfaceDescriptionInputs.uv3:                       output.uv3 =                         float4(input.texCoord3, 0.0f, 0.0f);

            $SurfaceDescriptionInputs.VertexColor:               output.VertexColor =                 input.color;

            $SurfaceDescriptionInputs.FaceSign:                  output.FaceSign =    input.isFrontFace;

            return output;
        }

    // existing HDRP code uses the combined function to go directly from packed to frag inputs
    FragInputs UnpackVaryingsMeshToFragInputs(PackedVaryingsMeshToPS input)
    {
        VaryingsMeshToPS unpacked= UnpackVaryingsMeshToPS(input);
        return BuildFragInputs(unpacked);
    }

    void BuildSurfaceData(FragInputs fragInputs, SurfaceDescription surfaceDescription, float3 V, out SurfaceData surfaceData)
    {
        // setup defaults -- these are used if the graph doesn't output a value
        ZERO_INITIALIZE(SurfaceData, surfaceData);
        surfaceData.ambientOcclusion =      1.0f;
        surfaceData.subsurfaceMask =        1.0f;

        // copy across graph values, if defined
        $SurfaceDescription.Albedo:               surfaceData.baseColor =             surfaceDescription.Albedo;
        $SurfaceDescription.Smoothness:           surfaceData.perceptualSmoothness =  surfaceDescription.Smoothness;
        $SurfaceDescription.Occlusion:            surfaceData.ambientOcclusion =      surfaceDescription.Occlusion;
        $SurfaceDescription.Metallic:             surfaceData.metallic =              surfaceDescription.Metallic;
        //                                  surfaceData.thickness =             surfaceDescription.Thickness;
        //                                  surfaceData.diffusionProfile =      surfaceDescription.DiffusionProfile;
        //                                  surfaceData.subsurfaceMask =        surfaceDescription.SubsurfaceMask;
        $SurfaceDescription.Specular:             surfaceData.specularColor =         surfaceDescription.Specular;

        // These static material feature allow compile time optimization
        surfaceData.materialFeatures = MATERIALFEATUREFLAGS_LIT_STANDARD;
#ifdef _MATERIAL_FEATURE_SUBSURFACE_SCATTERING
        surfaceData.materialFeatures |= MATERIALFEATUREFLAGS_LIT_SUBSURFACE_SCATTERING;
#endif
#ifdef _MATERIAL_FEATURE_TRANSMISSION
        surfaceData.materialFeatures |= MATERIALFEATUREFLAGS_LIT_TRANSMISSION;
#endif
#ifdef _MATERIAL_FEATURE_ANISOTROPY
        surfaceData.materialFeatures |= MATERIALFEATUREFLAGS_LIT_ANISOTROPY;
#endif
#ifdef _MATERIAL_FEATURE_CLEAR_COAT
        surfaceData.materialFeatures |= MATERIALFEATUREFLAGS_LIT_CLEAR_COAT;
#endif
#ifdef _MATERIAL_FEATURE_IRIDESCENCE
        surfaceData.materialFeatures |= MATERIALFEATUREFLAGS_LIT_IRIDESCENCE;
#endif
#ifdef _MATERIAL_FEATURE_SPECULAR_COLOR
        surfaceData.materialFeatures |= MATERIALFEATUREFLAGS_LIT_SPECULAR_COLOR;
#endif

        // tangent-space normal
        float3 normalTS =                   float3(0.0f, 0.0f, 1.0f);
        $SurfaceDescription.Normal:       normalTS =                   surfaceDescription.Normal;

        // compute world space normal
        GetNormalWS(fragInputs, normalTS, surfaceData.normalWS);

        // TODO: use surfaceDescription tangent definition for anisotropy
        surfaceData.tangentWS = normalize(fragInputs.worldToTangent[0].xyz);    // The tangent is not normalize in worldToTangent for mikkt. TODO: Check if it expected that we normalize with Morten. Tag: SURFACE_GRADIENT
        surfaceData.tangentWS = Orthonormalize(surfaceData.tangentWS, surfaceData.normalWS);

        // Init other parameters
        surfaceData.anisotropy = 0;
        surfaceData.coatMask = 0.0f;
        surfaceData.iridescenceThickness = 0.0;
        surfaceData.iridescenceMask = 1.0;

        // Transparency parameters
        // Use thickness from SSS
        surfaceData.ior = 1.0;
        surfaceData.transmittanceColor = float3(1.0, 1.0, 1.0);
        surfaceData.atDistance = 1000000.0;
        surfaceData.transmittanceMask = 0.0;

        // By default we use the ambient occlusion with Tri-ace trick (apply outside) for specular occlusion.
        // If user provide bent normal then we process a better term
        surfaceData.specularOcclusion = 1.0;
#if defined(_BENTNORMALMAP) && defined(_ENABLESPECULAROCCLUSION)
        // If we have bent normal and ambient occlusion, process a specular occlusion
        surfaceData.specularOcclusion = GetSpecularOcclusionFromBentAO(V, bentNormalWS, surfaceData);
#elif defined(_MASKMAP)
        surfaceData.specularOcclusion = GetSpecularOcclusionFromAmbientOcclusion(NdotV, surfaceData.ambientOcclusion, PerceptualSmoothnessToRoughness(surfaceData.perceptualSmoothness));
#endif
    }

    void GetSurfaceAndBuiltinData(FragInputs fragInputs, float3 V, inout PositionInputs posInput, out SurfaceData surfaceData, out BuiltinData builtinData)
    {
        // this applies the double sided tangent space correction -- see 'ApplyDoubleSidedFlipOrMirror()'
        $DoubleSided:           if (!fragInputs.isFrontFace) {
        $DoubleSided.Flip:          fragInputs.worldToTangent[1] = -fragInputs.worldToTangent[1];     // bitangent
        $DoubleSided.Flip:          fragInputs.worldToTangent[2] = -fragInputs.worldToTangent[2];     // normal
        $DoubleSided.Mirror:        fragInputs.worldToTangent[2] = -fragInputs.worldToTangent[2];     // normal
        $DoubleSided:           }

        SurfaceDescriptionInputs surfaceDescriptionInputs = FragInputsToSurfaceDescriptionInputs(fragInputs, V);
        SurfaceDescription surfaceDescription = SurfaceDescriptionFunction(surfaceDescriptionInputs);

        // Perform alpha test very early to save performance (a killed pixel will not sample textures)
        // TODO: split graph evaluation to grab just alpha dependencies first? tricky..
        $AlphaTest:     DoAlphaTest(surfaceDescription.Alpha, surfaceDescription.AlphaClipThreshold);

        BuildSurfaceData(fragInputs, surfaceDescription, V, surfaceData);

        // Builtin Data
        // For back lighting we use the oposite vertex normal 
        InitBuiltinData(surfaceDescription.Alpha, surfaceData.normalWS, -fragInputs.worldToTangent[2], fragInputs.positionRWS, fragInputs.texCoord1, fragInputs.texCoord2, builtinData);

$SurfaceDescription.Emission:     builtinData.emissiveColor =             surfaceDescription.Emission;

        builtinData.distortion =                float2(0.0, 0.0);           // surfaceDescription.Distortion -- if distortion pass
        builtinData.distortionBlur =            0.0;                        // surfaceDescription.DistortionBlur -- if distortion pass

        builtinData.depthOffset =               0.0;                        // ApplyPerPixelDisplacement(input, V, layerTexCoord, blendMasks); #ifdef _DEPTHOFFSET_ON : ApplyDepthOffsetPositionInput(V, depthOffset, GetWorldToHClipMatrix(), posInput);

        PostInitBuiltinData(V, posInput, surfaceData, builtinData);
    }

    //-------------------------------------------------------------------------------------
    // Pass Includes
    //-------------------------------------------------------------------------------------
${Includes}
    //-------------------------------------------------------------------------------------
    // End Pass Includes
    //-------------------------------------------------------------------------------------

    ENDHLSL
}