Ue4 Shader 使用

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我是靠谱客的博主执着大象，最近开发中收集的这篇文章主要介绍Ue4 Shader 使用，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

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    MSM_ThinTranslucent           UMETA(DisplayName="Thin Translucent"),
   // TODO:My
   MSM_MyShaderAa   UMETA(DisplayName = "My Shader Aa"),
   MSM_MyShaderAb   UMETA(DisplayName = "My Shader Ab"),

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        case MSM_ThinTranslucent:   ShadingModelName = TEXT("MSM_ThinTranslucent"); break;
       // TODO:My
       case MSM_MyShaderAa:   ShadingModelName = TEXT("MSM_MyShaderAa"); break;
       case MSM_MyShaderAb:   ShadingModelName = TEXT("MSM_MyShaderAb"); break;

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        const bool bSingleLayerWaterUsesSimpleShading = (IsSwitchPlatform(InPlatform) || IsVulkanMobileSM5Platform(InPlatform)) && IsForwardShadingEnabled(InPlatform);
       if (ShadingModels.HasShadingModel(MSM_SingleLayerWater) && bSingleLayerWaterUsesSimpleShading)
       {
           OutEnvironment.SetDefine(TEXT("SINGLE_LAYER_WATER_SIMPLE_FORWARD"), TEXT("1"));
       }
       // todo:My
       if (ShadingModels.HasShadingModel(MSM_MyShaderAa))
       {
           OutEnvironment.SetDefine(TEXT("MATERIAL_SHADINGMODEL_MYSHADERAA"), TEXT("1"));
           NumSetMaterials++;
       }
       if (ShadingModels.HasShadingModel(MSM_MyShaderAb))
       {
           OutEnvironment.SetDefine(TEXT("MATERIAL_SHADINGMODEL_MYSHADERAB"), TEXT("1"));
           NumSetMaterials++;
       }

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    case MP_Metallic:
       CustomPinNames.Add({MSM_Hair, "Scatter"});
       CustomPinNames.Add({ MSM_MyShaderAa, "MetallicMyShaderAa" });
       CustomPinNames.Add({ MSM_MyShaderAb, "MetallicMyShaderAb" });
       return FText::FromString(GetPinNameFromShadingModelField(Material->GetShadingModels(), CustomPinNames, "Metallic"));

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    case MP_Specular:
       return Material->GetShadingModels() == MSM_MyShaderAa ? LOCTEXT("SpecularMyShaderAa", "SpecularMyShaderAa") : LOCTEXT("Specular", "Specular");
   case MP_Roughness:
       return Material->GetShadingModels() == MSM_MyShaderAa ? LOCTEXT("RoughnessMyShaderAa", "RoughnessMyShaderAa") : LOCTEXT("Roughness", "Roughness");

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    case MP_SubsurfaceColor:
       CustomPinNames.Add({MSM_Cloth, "Fuzz Color"});
       CustomPinNames.Add({ MSM_MyShaderAa, "SubsurfaceColorMyShaderAa" });
       CustomPinNames.Add({ MSM_MyShaderAb, "SubsurfaceColorMyShaderAb" });
       return FText::FromString(GetPinNameFromShadingModelField(Material->GetShadingModels(), CustomPinNames, "Subsurface Color"));
   case MP_CustomData0:
       CustomPinNames.Add({ MSM_ClearCoat, "Clear Coat" });
       CustomPinNames.Add({MSM_Hair, "Backlit"});
       CustomPinNames.Add({MSM_Cloth, "Cloth"});
       CustomPinNames.Add({MSM_Eye, "Iris Mask"});
       CustomPinNames.Add({ MSM_MyShaderAa, "CustomData0MyShaderAa" });
       CustomPinNames.Add({ MSM_MyShaderAb, "CustomData0MyShaderAa" });
       return FText::FromString(GetPinNameFromShadingModelField(Material->GetShadingModels(), CustomPinNames, "Custom Data 0"));

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修改前

#define WRITES_CUSTOMDATA_TO_GBUFFER (USES_GBUFFER && (MATERIAL_SHADINGMODEL_SUBSURFACE || MATERIAL_SHADINGMODEL_PREINTEGRATED_SKIN || MATERIAL_SHADINGMODEL_SUBSURFACE_PROFILE || MATERIAL_SHADINGMODEL_CLEAR_COAT || MATERIAL_SHADINGMODEL_TWOSIDED_FOLIAGE || MATERIAL_SHADINGMODEL_HAIR || MATERIAL_SHADINGMODEL_CLOTH || MATERIAL_SHADINGMODEL_EYE))

修改后

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修改前

#if MATERIAL_SHADINGMODEL_CLOTH
       else if (ShadingModel == SHADINGMODELID_CLOTH)
       {
           SubsurfaceColor = SubsurfaceData.rgb;
       }
#endif

修改后

#if MATERIAL_SHADINGMODEL_CLOTH || MATERIAL_SHADINGMODEL_MYSHADERAA || MATERIAL_SHADINGMODEL_MYSHADERAB
       else if (ShadingModel == SHADINGMODELID_CLOTH || ShadingModel == SHADINGMODELID_MYSHADERAA || ShadingModel == SHADINGMODELID_MYSHADERAB)
       {
           SubsurfaceColor = SubsurfaceData.rgb;
       }
#endif

修正修改

修改前

#if MATERIAL_SHADINGMODEL_SUBSURFACE || MATERIAL_SHADINGMODEL_PREINTEGRATED_SKIN || MATERIAL_SHADINGMODEL_SUBSURFACE_PROFILE || MATERIAL_SHADINGMODEL_TWOSIDED_FOLIAGE || MATERIAL_SHADINGMODEL_CLOTH || MATERIAL_SHADINGMODEL_EYE
   if (ShadingModel == SHADINGMODELID_SUBSURFACE || ShadingModel == SHADINGMODELID_PREINTEGRATED_SKIN || ShadingModel == SHADINGMODELID_SUBSURFACE_PROFILE || ShadingModel == SHADINGMODELID_TWOSIDED_FOLIAGE || ShadingModel == SHADINGMODELID_CLOTH || ShadingModel == SHADINGMODELID_EYE)
   {
       float4 SubsurfaceData = GetMaterialSubsurfaceData(PixelMaterialInputs);

       if (false) // Dummy if to make the ifdef logic play nicely
       {
       }
#if MATERIAL_SHADINGMODEL_SUBSURFACE || MATERIAL_SHADINGMODEL_PREINTEGRATED_SKIN || MATERIAL_SHADINGMODEL_TWOSIDED_FOLIAGE
       else if (ShadingModel == SHADINGMODELID_SUBSURFACE || ShadingModel == SHADINGMODELID_PREINTEGRATED_SKIN || ShadingModel == SHADINGMODELID_TWOSIDED_FOLIAGE)
       {
           SubsurfaceColor = SubsurfaceData.rgb * View.DiffuseOverrideParameter.w + View.DiffuseOverrideParameter.xyz;
       }
#endif
#if MATERIAL_SHADINGMODEL_CLOTH
       else if (ShadingModel == SHADINGMODELID_CLOTH)
       {
           SubsurfaceColor = SubsurfaceData.rgb;
       }
#endif

SubsurfaceProfile = SubsurfaceData.a;
}
#endif

修改后

if (ShadingModel == SHADINGMODELID_SUBSURFACE || ShadingModel == SHADINGMODELID_PREINTEGRATED_SKIN || ShadingModel == SHADINGMODELID_SUBSURFACE_PROFILE || ShadingModel == SHADINGMODELID_TWOSIDED_FOLIAGE || ShadingModel == SHADINGMODELID_CLOTH || ShadingModel == SHADINGMODELID_EYE || ShadingModel == SHADINGMODELID_MYSHADERAA || ShadingModel == SHADINGMODELID_MYSHADERAB)

{

float4 SubsurfaceData = GetMaterialSubsurfaceData(PixelMaterialInputs);

if (false) // Dummy if to make the ifdef logic play nicely

{

}

#if MATERIAL_SHADINGMODEL_SUBSURFACE || MATERIAL_SHADINGMODEL_PREINTEGRATED_SKIN || MATERIAL_SHADINGMODEL_TWOSIDED_FOLIAGE

else if (ShadingModel == SHADINGMODELID_SUBSURFACE || ShadingModel == SHADINGMODELID_PREINTEGRATED_SKIN || ShadingModel == SHADINGMODELID_TWOSIDED_FOLIAGE)

{

SubsurfaceColor = SubsurfaceData.rgb * View.DiffuseOverrideParameter.w + View.DiffuseOverrideParameter.xyz;

}

#endif

#if MATERIAL_SHADINGMODEL_CLOTH || MATERIAL_SHADINGMODEL_MYSHADERAA || MATERIAL_SHADINGMODEL_MYSHADERAB

else if (ShadingModel == SHADINGMODELID_CLOTH || ShadingModel == SHADINGMODELID_MYSHADERAA || ShadingModel == SHADINGMODELID_MYSHADERAB)

{

SubsurfaceColor = SubsurfaceData.rgb;

}

#endif

SubsurfaceProfile = SubsurfaceData.a;

}

#endif

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修改前

// So that the following code can still use DiffuseColor and SpecularColor.
GBuffer.SpecularColor = ComputeF0(Specular, BaseColor, Metallic);

修改后

// So that the following code can still use DiffuseColor and SpecularColor.
GBuffer.SpecularColor = ComputeF0(Specular, BaseColor, Metallic);

#if MATERIAL_SHADINGMODEL_MYSHADERAA || MATERIAL_SHADINGMODEL_MYSHADERAB
   if (GBuffer.ShadingModelID == SHADINGMODELID_MYSHADERAA || GBuffer.ShadingModelID == SHADINGMODELID_MYSHADERAB)
   {
       GBuffer.SpecularColor = float3(0.0f, 0.0f, 0.0f);
   }
#endif

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修改前

GBuffer.DiffuseColor = BaseColor - BaseColor * Metallic;

修改后

GBuffer.DiffuseColor = BaseColor - BaseColor * Metallic;

#if MATERIAL_SHADINGMODEL_MYSHADERAA || MATERIAL_SHADINGMODEL_MYSHADERAB
   if (GBuffer.ShadingModelID == SHADINGMODELID_MYSHADERAA || GBuffer.ShadingModelID == SHADINGMODELID_MYSHADERAB)
   {
       GBuffer.DiffuseColor = float3(0.0f, 0.0f, 0.0f);
   }
#endif

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修改前

LightAccumulator.EstimatedCost += 0.3f; // add the cost of getting the shadow terms

       BRANCH
       if( Shadow.SurfaceShadow + Shadow.TransmissionShadow > 0 )
       {
           const bool bNeedsSeparateSubsurfaceLightAccumulation = UseSubsurfaceProfile(GBuffer.ShadingModelID);
           float3 LightColor = LightData.Color;

#if NON_DIRECTIONAL_DIRECT_LIGHTING
float Lighting;

           if( LightData.bRectLight )
           {
               FRect Rect = GetRect( ToLight, LightData );

               Lighting = IntegrateLight( Rect, SourceTexture);
           }
           else
           {
               FCapsuleLight Capsule = GetCapsule( ToLight, LightData );

Lighting = IntegrateLight( Capsule, LightData.bInverseSquared );
}

           float3 LightingDiffuse = Diffuse_Lambert( GBuffer.DiffuseColor ) * Lighting;
           LightAccumulator_AddSplit(LightAccumulator, LightingDiffuse, 0.0f, 0, LightColor * LightMask * Shadow.SurfaceShadow, bNeedsSeparateSubsurfaceLightAccumulation);
       #else
           FDirectLighting Lighting;

           if (LightData.bRectLight)
           {
               FRect Rect = GetRect( ToLight, LightData );

               #if REFERENCE_QUALITY
                   Lighting = IntegrateBxDF( GBuffer, N, V, Rect, Shadow, SourceTexture, SVPos );
               #else
                   Lighting = IntegrateBxDF( GBuffer, N, V, Rect, Shadow, SourceTexture);
               #endif
           }
           else
           {
               FCapsuleLight Capsule = GetCapsule( ToLight, LightData );

               #if REFERENCE_QUALITY
                   Lighting = IntegrateBxDF( GBuffer, N, V, Capsule, Shadow, SVPos );
               #else
                   Lighting = IntegrateBxDF( GBuffer, N, V, Capsule, Shadow, LightData.bInverseSquared );
               #endif
           }

           Lighting.Specular *= LightData.SpecularScale;

           LightAccumulator_AddSplit( LightAccumulator, Lighting.Diffuse, Lighting.Specular, Lighting.Diffuse, LightColor * LightMask * Shadow.SurfaceShadow, bNeedsSeparateSubsurfaceLightAccumulation );
           LightAccumulator_AddSplit( LightAccumulator, Lighting.Transmission, 0.0f, Lighting.Transmission, LightColor * LightMask * Shadow.TransmissionShadow, bNeedsSeparateSubsurfaceLightAccumulation );

           LightAccumulator.EstimatedCost += 0.4f;       // add the cost of the lighting computations (should sum up to 1 form one light)
       #endif
       }
   }

修改后

LightAccumulator.EstimatedCost += 0.3f; // add the cost of getting the shadow terms

       BRANCH
       #if MATERIAL_SHADINGMODEL_MYSHADERAA || MATERIAL_SHADINGMODEL_MYSHADERAB
       if (GBuffer.ShadingModelID == SHADINGMODELID_MYSHADERAA || GBuffer.ShadingModelID == SHADINGMODELID_MYSHADERAB)
       {
           float3 LightColor = LightData.Color;

           float3 SSS = float3(GBuffer.CustomData.r, GBuffer.CustomData.g, GBuffer.CustomData.b);
           float SpecStrength = GBuffer.Metallic;
           float ShadowThreshold = GBuffer.Specular;
           float SpecularSize = GBuffer.Roughness;
           float InnerLine = GBuffer.CustomData.a;

           // 纹理数据处理
           float3 BrightColor = GBuffer.BaseColor;
           float3 ShadowColor = GBuffer.BaseColor * SSS;

           // 这里我觉得内部描边的颜色不够明显，于是乘上了0.5
           if (InnerLine < 0.8f)
           {
               InnerLine *= 0.5f;
           }
           float3 InnerLineColor = float3(InnerLine, InnerLine, InnerLine);

float NdotL = dot(L, N) * Shadow.SurfaceShadow;
float NdotH = dot(normalize(L + V), N);

ShadowThreshold = step(ShadowThreshold, NdotL);

float3 Diffuse = InnerLineColor * LightColor * lerp(ShadowColor, BrightColor, ShadowThreshold);
float3 Specular = LightColor * BrightColor * ShadowThreshold * InnerLineColor * step(0.2f, SpecularSize * pow(NdotH, SpecStrength));

           LightAccumulator.TotalLight = Diffuse + Specular;
       }
       else
       {
       #endif
       if( Shadow.SurfaceShadow + Shadow.TransmissionShadow > 0 )
       {
           const bool bNeedsSeparateSubsurfaceLightAccumulation = UseSubsurfaceProfile(GBuffer.ShadingModelID);
           float3 LightColor = LightData.Color;

#if NON_DIRECTIONAL_DIRECT_LIGHTING
float Lighting;

           if( LightData.bRectLight )
           {
               FRect Rect = GetRect( ToLight, LightData );

               Lighting = IntegrateLight( Rect, SourceTexture);
           }
           else
           {
               FCapsuleLight Capsule = GetCapsule( ToLight, LightData );

Lighting = IntegrateLight( Capsule, LightData.bInverseSquared );
}

           if (LightData.bRectLight)
           {
               FRect Rect = GetRect( ToLight, LightData );

           LightAccumulator.EstimatedCost += 0.4f;       // add the cost of the lighting computations (should sum up to 1 form one light)
       #endif
       #if MATERIAL_SHADINGMODEL_MYSHADERAA || MATERIAL_SHADINGMODEL_MYSHADERAB
       }
       #endif
       }
   }

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修改前

else
   {
       Color.rgb *= EnvBRDF( SpecularColor, GBuffer.Roughness, NoV );
   }

修改后

    else if(GBuffer.ShadingModelID == SHADINGMODELID_MYSHADERAA || GBuffer.ShadingModelID == SHADINGMODELID_MYSHADERAA)
   {
       return float3(0.0f, 0.0f, 0.0f);
   }
   else
   {
       Color.rgb *= EnvBRDF( SpecularColor, GBuffer.Roughness, NoV );
   }

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修改前

#define SHADINGMODELID_THIN_TRANSLUCENT 11
#define SHADINGMODELID_NUM 12

修改后

#define SHADINGMODELID_MYSHADERAA       12
#define SHADINGMODELID_MYSHADERAB       13
#define SHADINGMODELID_NUM                   14

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修改前

最后添加

修改后

#if MATERIAL_SHADINGMODEL_MYSHADERAA || MATERIAL_SHADINGMODEL_MYSHADERAB
   else if (ShadingModel == SHADINGMODELID_MYSHADERAA || ShadingModel == SHADINGMODELID_MYSHADERAB)
   {
       GBuffer.CustomData.rgb = float4(SubsurfaceColor, GetMaterialCustomData0(MaterialParameters));
   }
#endif

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Shader Model C++ 和 hlsl 对应的地方，

注意， C++ 中的值和 hlsl 中的值一定要相等

C++