SurfaceDescriptionInputs BuildSurfaceDescriptionInputs(Varyings input)
{
    SurfaceDescriptionInputs output;
    ZERO_INITIALIZE(SurfaceDescriptionInputs, output);

    $splice(CustomInterpolatorCopyToSDI)

    $SurfaceDescriptionInputs.WorldSpaceNormal:                         // must use interpolated tangent, bitangent and normal before they are normalized in the pixel shader.
    $SurfaceDescriptionInputs.WorldSpaceNormal:                         float3 unnormalizedNormalWS =                       input.normalWS;
    $SurfaceDescriptionInputs.WorldSpaceNormal:                         const float renormFactor =                          1.0 / length(unnormalizedNormalWS);

    $SurfaceDescriptionInputs.WorldSpaceBiTangent:                      // use bitangent on the fly like in hdrp
    $SurfaceDescriptionInputs.WorldSpaceBiTangent:                      // IMPORTANT! If we ever support Flip on double sided materials ensure bitangent and tangent are NOT flipped.
    $SurfaceDescriptionInputs.WorldSpaceBiTangent:                      float crossSign =                                   (input.tangentWS.w > 0.0 ? 1.0 : -1.0) * GetOddNegativeScale();
    $SurfaceDescriptionInputs.WorldSpaceBiTangent:                      float3 bitang =                                     crossSign * cross(input.normalWS.xyz, input.tangentWS.xyz);

    $SurfaceDescriptionInputs.WorldSpaceNormal:                         output.WorldSpaceNormal =                           renormFactor*input.normalWS.xyz;      // we want a unit length Normal Vector node in shader graph
    $SurfaceDescriptionInputs.ObjectSpaceNormal:                        output.ObjectSpaceNormal =                          normalize(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:                        // to preserve mikktspace compliance we use same scale renormFactor as was used on the normal.
    $SurfaceDescriptionInputs.WorldSpaceTangent:                        // This is explained in section 2.2 in "surface gradient based bump mapping framework"
    $SurfaceDescriptionInputs.WorldSpaceTangent:                        output.WorldSpaceTangent =                          renormFactor*input.tangentWS.xyz;
    $SurfaceDescriptionInputs.WorldSpaceBiTangent:                      output.WorldSpaceBiTangent =                        renormFactor*bitang;

    $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.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 =                    GetWorldSpaceNormalizeViewDir(input.positionWS);
    $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 =                  TransformWorldToTangent(output.WorldSpaceViewDirection, tangentSpaceTransform);
    $SurfaceDescriptionInputs.WorldSpacePosition:                       output.WorldSpacePosition =                         input.positionWS;
    $SurfaceDescriptionInputs.ObjectSpacePosition:                      output.ObjectSpacePosition =                        TransformWorldToObject(input.positionWS);
    $SurfaceDescriptionInputs.ViewSpacePosition:                        output.ViewSpacePosition =                          TransformWorldToView(input.positionWS);
    $SurfaceDescriptionInputs.TangentSpacePosition:                     output.TangentSpacePosition =                       float3(0.0f, 0.0f, 0.0f);
    $SurfaceDescriptionInputs.AbsoluteWorldSpacePosition:               output.AbsoluteWorldSpacePosition =                 GetAbsolutePositionWS(input.positionWS);
    $SurfaceDescriptionInputs.WorldSpacePositionPredisplacement:        output.WorldSpacePositionPredisplacement =          input.positionPredisplacementWS;
    $SurfaceDescriptionInputs.ObjectSpacePositionPredisplacement:       output.ObjectSpacePositionPredisplacement =         TransformWorldToObject(input.positionPredisplacementWS);
    $SurfaceDescriptionInputs.ViewSpacePositionPredisplacement:         output.ViewSpacePositionPredisplacement =           TransformWorldToView(input.positionPredisplacementWS);
    $SurfaceDescriptionInputs.TangentSpacePositionPredisplacement:      output.TangentSpacePositionPredisplacement =        float3(0.0f, 0.0f, 0.0f);
    $SurfaceDescriptionInputs.AbsoluteWorldSpacePositionPredisplacement:output.AbsoluteWorldSpacePositionPredisplacement =  GetAbsolutePositionWS(input.positionPredisplacementWS);
    $SurfaceDescriptionInputs.ScreenPosition:                           output.ScreenPosition =                             ComputeScreenPos(TransformWorldToHClip(input.positionWS), _ProjectionParams.x);

    #if UNITY_UV_STARTS_AT_TOP
    $SurfaceDescriptionInputs.PixelPosition:                            output.PixelPosition = float2(input.positionCS.x, (_ProjectionParams.x < 0) ? (_ScreenParams.y - input.positionCS.y) : input.positionCS.y);
    #else
    $SurfaceDescriptionInputs.PixelPosition:                            output.PixelPosition = float2(input.positionCS.x, (_ProjectionParams.x > 0) ? (_ScreenParams.y - input.positionCS.y) : input.positionCS.y);
    #endif

    $SurfaceDescriptionInputs.NDCPosition:                              output.NDCPosition = output.PixelPosition.xy / _ScreenParams.xy;
    $SurfaceDescriptionInputs.NDCPosition:                              output.NDCPosition.y = 1.0f - output.NDCPosition.y;

    $SurfaceDescriptionInputs.uv0:                                      output.uv0 =                                        input.texCoord0;
    $SurfaceDescriptionInputs.uv1:                                      output.uv1 =                                        input.texCoord1;
    $SurfaceDescriptionInputs.uv2:                                      output.uv2 =                                        input.texCoord2;
    $SurfaceDescriptionInputs.uv3:                                      output.uv3 =                                        input.texCoord3;
    $SurfaceDescriptionInputs.VertexColor:                              output.VertexColor =                                input.color;
    $SurfaceDescriptionInputs.VertexID:                                 output.VertexID =                                   input.vertexID;
#if UNITY_ANY_INSTANCING_ENABLED
    $SurfaceDescriptionInputs.InstanceID:                               output.InstanceID =                                 unity_InstanceID;
#else // TODO: XR support for procedural instancing because in this case UNITY_ANY_INSTANCING_ENABLED is not defined and instanceID is incorrect.
    $SurfaceDescriptionInputs.InstanceID:                               output.InstanceID =                                 input.instanceID;
#endif
    $SurfaceDescriptionInputs.TimeParameters:                           output.TimeParameters =                             _TimeParameters.xyz; // This is mainly for LW as HD overwrite this value
#if defined(SHADER_STAGE_FRAGMENT) && defined(VARYINGS_NEED_CULLFACE)
#define BUILD_SURFACE_DESCRIPTION_INPUTS_OUTPUT_FACESIGN                output.FaceSign =                                   IS_FRONT_VFACE(input.cullFace, true, false);
#else
#define BUILD_SURFACE_DESCRIPTION_INPUTS_OUTPUT_FACESIGN
#endif
    $SurfaceDescriptionInputs.FaceSign:                                 BUILD_SURFACE_DESCRIPTION_INPUTS_OUTPUT_FACESIGN
#undef BUILD_SURFACE_DESCRIPTION_INPUTS_OUTPUT_FACESIGN

    return output;
}