311 lines
14 KiB
Markdown
311 lines
14 KiB
Markdown
---
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title: JasonMa渲染方案分析
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date: 2024-01-25 16:02:26
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excerpt:
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tags:
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rating: ⭐
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---
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# 前言
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截止版本UE5.3.2。添加了一种新的GBuffer精度格式GBT_Uint_32_32_32_32，以及RT7。
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修改内容：
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- GBufferPostDecode.ush：在GBufferPostDecode中给FGBufferData添加InitMooaToonContext()逻辑
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- SceneRendering.cpp：Debug用的渲染变量调节，并且在FViewInfo::SetupUniformBufferParameters()添加设置相关变量的逻辑。
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- 其他：
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- MaterialBaking：ExportMaterialProxy.h
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- MaterialEditor：MaterialEditor.cpp
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- PixelInspector：PixelInspectorResult.cpp、PixelInspectorResult.h
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# ToonShadingCommon.ush
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除了一下工具函数，主要实现：
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1. GBuffer的一些Encode / Decode Helper函数。
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2. 用于存储数据的struct FMooaToonData、FMooaToonContext。
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3. 针对上面2个结构体编码与解码的函数。FMooaCustomPayload用于光追Shader。
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## 数据结构体
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```c++
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struct FMooaToonContext
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{
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FMooaToonData MooaToonData;
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bool IsMainLight;
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float3 LightColor;
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bool IsEditorPreviewWorldType;
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float Exposure;
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uint2 PixelPos; // SVPos.xy
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};
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struct FMooaToonData
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{
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// Diffuse
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float3 MainLightShadowColor;
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float MainLightShadowValueOffset;
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float MainLightShadowApplyLightColor;
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float OtherLightDiffuseThreshold;
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float OtherLightDiffuseFeather;
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float GlobalIlluminationIntensity;
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float GlobalIlluminationDirectionality;
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// Specular
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float3 SpecularColor;
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float SpecularThreshold;
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float SpecularFeather;
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float ReflectionIntensity;
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bool IsPBRSpecular;
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float RimLightIntensity;
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float RimLightWidth;
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float RimLightAngle;
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float RimLightDepthThreshold;
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// Ray Tracing Shadow
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uint Stencil;
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uint RayTracingShadowFlag;
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float HairShadowWidth;
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float HairShadowIntensity;
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// Unused
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float CustomData3;
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};
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```
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## Encode/Decode
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这里推荐使用计算器进行计算更加好理解。
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```c++
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//取得指定Bits位数的最大数值，8位 => 255
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uint GetBitsMaxValue(int Bits = 8) {return (1L << Bits) - 1;}
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//将2个uint合并1个uint，将Src1移动Scr2的位数后，将2者进行或运算合并到一起。
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uint EncodeUint2ToUint(uint Src1, uint Src2, int BitsSrc1 = 8, int BitsSrc2 = 8)
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{
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return ((Src1 & GetBitsMaxValue(BitsSrc1)) << BitsSrc2) |
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(Src2 & GetBitsMaxValue(BitsSrc2));
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}
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//将2个uint合并1个uint后转换成浮点数（0~1）
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float EncodeUint2ToFloat(uint Src1, uint Src2, int BitsSrc1 = 8, int BitsSrc2 = 8)
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{
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return float(EncodeUint2ToUint(Src1, Src2, BitsSrc1, BitsSrc2)) / GetBitsMaxValue(BitsSrc1 + BitsSrc2);
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}
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//将合并后Uint还原成2个uint
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void DecodeUint2FromUint(uint Src, out uint Dst1, out uint Dst2, int BitsDst1 = 8, int BitsDst2 = 8)
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{
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Dst1 = (Src >> BitsDst2) & GetBitsMaxValue(BitsDst1);
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Dst2 = Src & GetBitsMaxValue(BitsDst2);
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}
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//将合并后float（0~1）还原成2个uint
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void DecodeUint2FromFloat(float Src, out uint Dst1, out uint Dst2, int BitsDst1 = 8, int BitsDst2 = 8)
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{
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uint FloatToUint = uint(Src * GetBitsMaxValue(BitsDst1 + BitsDst2));
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DecodeUint2FromUint(FloatToUint, Dst1, Dst2, BitsDst1, BitsDst2);
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}
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//将float（0~1）编码成uint
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uint EncodeFloatToUint(float Src1, int BitsSrc1 = 8)
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{
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return saturate(Src1) * GetBitsMaxValue(BitsSrc1);
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}
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uint EncodeFloat2ToUint(float Src1, float Src2, int BitsSrc1 = 8, int BitsSrc2 = 8)
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{
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return EncodeUint2ToUint(EncodeFloatToUint(Src1, BitsSrc1), EncodeFloatToUint(Src2, BitsSrc2), BitsSrc1, BitsSrc2);
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}
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float EncodeFloat2ToFloat(float Src1, float Src2, int BitsSrc1 = 8, int BitsSrc2 = 8)
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{
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return EncodeUint2ToFloat(EncodeFloatToUint(Src1, BitsSrc1), EncodeFloatToUint(Src2, BitsSrc2), BitsSrc1, BitsSrc2);
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}
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//将uint还原成float（0~1）
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float DecodeFloatFromUint(uint Src, int BitsDst1 = 8)
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{
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return float(Src & GetBitsMaxValue(BitsDst1)) / GetBitsMaxValue(BitsDst1);
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}
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void DecodeFloat2FromUint(uint Src, out float Dst1, out float Dst2, int BitsDst1 = 8, int BitsDst2 = 8)
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{
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uint OutUint1, OutUint2;
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DecodeUint2FromUint(Src, OutUint1, OutUint2, BitsDst1, BitsDst2);
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Dst1 = DecodeFloatFromUint(OutUint1, BitsDst1);
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Dst2 = DecodeFloatFromUint(OutUint2, BitsDst2);
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}
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void DecodeFloat2FromFloat(float Src, out float Dst1, out float Dst2, int BitsDst1 = 8, int BitsDst2 = 8)
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{
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uint OutUint1, OutUint2;
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DecodeUint2FromFloat(Src, OutUint1, OutUint2, BitsDst1, BitsDst2);
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Dst1 = DecodeFloatFromUint(OutUint1, BitsDst1);
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Dst2 = DecodeFloatFromUint(OutUint2, BitsDst2);
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```
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## 结构体与GBuffer Encode/Decode
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```c++
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void EncodeMooaToonData(FMooaToonData MooaToonData, out float4 MooaToonDataA, out float4 MooaToonDataB, out float4 MooaToonDataC)
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{
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MooaToonDataA = (float4)0;
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MooaToonDataB = (float4)0;
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MooaToonDataC = (float4)0;
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MooaToonDataA.x = EncodeFloat2ToUint(MooaToonData.OtherLightDiffuseThreshold, MooaToonData.OtherLightDiffuseFeather);
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MooaToonDataA.y = EncodeFloat2ToUint(MooaToonData.GlobalIlluminationIntensity, MooaToonData.GlobalIlluminationDirectionality, 6, 6);
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MooaToonDataA.z = EncodeFloat2ToUint(MooaToonData.MainLightShadowApplyLightColor, MooaToonData.CustomData3, 6, 4);
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MooaToonDataA.w = EncodeUint2ToUint(
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EncodeFloatToUint(MooaToonData.HairShadowWidth, 6),
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EncodeUint2ToUint(
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MooaToonData.Stencil,
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EncodeUint2ToUint(MooaToonData.RayTracingShadowFlag, MooaToonData.IsPBRSpecular ? 1 : 0, 2, 1),
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5, 3),
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6, 8);
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MooaToonDataB.x = EncodeFloat2ToUint(MooaToonData.SpecularColor.r, MooaToonData.SpecularColor.g);
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MooaToonDataB.y = EncodeUint2ToUint(
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EncodeFloatToUint(MooaToonData.SpecularColor.b),
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EncodeFloat2ToUint(MooaToonData.ReflectionIntensity, MooaToonData.HairShadowIntensity, 6, 6),
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8, 12);
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MooaToonDataB.z = EncodeUint2ToUint(
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EncodeFloat2ToUint(MooaToonData.SpecularThreshold, MooaToonData.SpecularFeather),
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EncodeFloatToUint(MooaToonData.RimLightIntensity, 6),
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16, 6);
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MooaToonDataB.w = EncodeUint2ToUint(
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EncodeFloat2ToUint(MooaToonData.RimLightWidth, MooaToonData.RimLightAngle, 6, 6),
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EncodeFloatToUint(MooaToonData.RimLightDepthThreshold, 6),
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12, 6);
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MooaToonDataC.rgb = saturate(MooaToonData.MainLightShadowColor);
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MooaToonDataC.a = saturate(MooaToonData.MainLightShadowValueOffset);
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}
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FMooaToonData DecodeMooaToonData(float4 MooaToonDataA, float4 MooaToonDataB, float4 MooaToonDataC)
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{
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FMooaToonData MooaToonData = (FMooaToonData)0;
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uint Out0, Out1, Out2, Out3;
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DecodeFloat2FromUint(MooaToonDataA.x, MooaToonData.OtherLightDiffuseThreshold, MooaToonData.OtherLightDiffuseFeather);
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DecodeFloat2FromUint(MooaToonDataA.y, MooaToonData.GlobalIlluminationIntensity, MooaToonData.GlobalIlluminationDirectionality, 6, 6);
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DecodeFloat2FromUint(MooaToonDataA.z, MooaToonData.MainLightShadowApplyLightColor, MooaToonData.CustomData3, 6, 4);
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DecodeUint2FromUint(MooaToonDataA.w, Out0, Out1, 6, 8);
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MooaToonData.HairShadowWidth = DecodeFloatFromUint(Out0, 6);
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DecodeUint2FromUint(Out1, MooaToonData.Stencil, Out2, 5, 3);
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DecodeUint2FromUint(Out2, MooaToonData.RayTracingShadowFlag, MooaToonData.IsPBRSpecular, 2, 1);
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DecodeFloat2FromUint(MooaToonDataB.x, MooaToonData.SpecularColor.r, MooaToonData.SpecularColor.g);
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DecodeUint2FromUint(MooaToonDataB.y, Out0, Out1, 8, 12);
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MooaToonData.SpecularColor.b = DecodeFloatFromUint(Out0);
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DecodeFloat2FromUint(Out1, MooaToonData.ReflectionIntensity, MooaToonData.HairShadowIntensity, 6, 6);
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DecodeUint2FromUint(MooaToonDataB.z, Out0, Out1, 16, 6);
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DecodeFloat2FromUint(Out0, MooaToonData.SpecularThreshold, MooaToonData.SpecularFeather);
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MooaToonData.RimLightIntensity = DecodeFloatFromUint(Out1, 6);
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DecodeUint2FromUint(MooaToonDataB.w, Out0, Out1, 12, 6);
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DecodeFloat2FromUint(Out0, MooaToonData.RimLightWidth, MooaToonData.RimLightAngle, 6, 6);
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MooaToonData.RimLightDepthThreshold = DecodeFloatFromUint(Out1, 6);
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MooaToonData.MainLightShadowColor = MooaToonDataC.rgb;
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MooaToonData.MainLightShadowValueOffset = MooaToonDataC.a;
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return MooaToonData;
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}
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uint4 EncodeMooaToonDataToBuffer(FMooaToonData MooaToonData)
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{
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MooaToonData.SpecularColor = LinearToSrgb(saturate(MooaToonData.SpecularColor));
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float4 MooaToonDataA, MooaToonDataB, MooaToonDataC;
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uint4 Out;
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EncodeMooaToonData(MooaToonData, MooaToonDataA, MooaToonDataB, MooaToonDataC);
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Out.x = EncodeUint2ToUint(MooaToonDataA.x, MooaToonDataB.x, 16, 16);
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Out.y = EncodeUint2ToUint(MooaToonDataA.y, MooaToonDataB.y, 12, 20);
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Out.z = EncodeUint2ToUint(MooaToonDataA.z, MooaToonDataB.z, 10, 22);
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Out.w = EncodeUint2ToUint(MooaToonDataA.w, MooaToonDataB.w, 14, 18);
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return Out;
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}
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FMooaToonData DecodeMooaToonDataFromBuffer(uint4 ToonBufferA, float4 CustomData)
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{
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uint4 Out0, Out1;
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DecodeUint2FromUint(ToonBufferA.x, Out0.x, Out1.x, 16, 16);
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DecodeUint2FromUint(ToonBufferA.y, Out0.y, Out1.y, 12, 20);
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DecodeUint2FromUint(ToonBufferA.z, Out0.z, Out1.z, 10, 22);
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DecodeUint2FromUint(ToonBufferA.w, Out0.w, Out1.w, 14, 18);
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float4 MooaToonDataA = Out0;
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float4 MooaToonDataB = Out1;
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FMooaToonData MooaToonData = DecodeMooaToonData(MooaToonDataA, MooaToonDataB, CustomData);
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MooaToonData.MainLightShadowColor = sRGBToLinear(MooaToonData.MainLightShadowColor);
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MooaToonData.SpecularColor = sRGBToLinear(MooaToonData.SpecularColor);
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return MooaToonData;
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}
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```
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# BasePassPixelShader.usf
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## GBuffer
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```c++
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/*
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* CustomData (GBufferD) (MP_MooaToonDataC) (0~1) = MainLightShadowColor(8 8 8) MainLightShadowValueOffset(8)
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*
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* ToonBufferA (RGBA Uint 32)
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* xyzw: MooaToonDataA.xyzw | MooaToonDataB.xyzw (32 bits total)
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*
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* MP_MooaToonDataA (float4, max storage 23 bits uint)
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* x: OtherLightDiffuseThreshold(8) OtherLightDiffuseFeather(8)
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* y: GlobalIlluminationIntensity(6) GlobalIlluminationDirectionality(6)
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* z: MainLightShadowApplyLightColor(6) CustomData3(4)
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* w: HairShadowWidth(6) Stencil(5) RayTracingShadowFlag(2) IsPBRSpecular(1)
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*
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* MP_MooaToonDataB (float4, max storage 23 bits uint)
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* x: SpecularColor.x(8) SpecularColor.y(8)
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* y: SpecularColor.z(8) ReflectionIntensity(6) HairShadowIntensity(6)
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* z: SpecularThreshold(8) SpecularFeather(8) RimLightIntensity(6)
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* w: RimLightWidth(6) RimLightAngle(6) RimLightDepthThreshold(6)
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*
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*
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* Tips: store sRGB Color to maximize accuracy
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*/
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```
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>PS.float4, max storage 23 bits uint
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>Jason自己添加了GBT_Uint_32_32_32_32的GBuffer格式。
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- MooaToonDataA (RGBA Uint 32 **ToonBufferA**)
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- R（4+4）：OtherLightDiffuseThreshold + OtherLightDiffuseFeather
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- G（4+4）：GlobalIlluminationIntensity + GlobalIlluminationDirectionality
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- B（4+4）：MainLightShadowApplyLightColor + CustomData3
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- A （6+5+2+1）：HairShadowWidth + Stencil + RayTracingShadowFlag + IsPBRSpecular
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- MooaToonDataB (RGBA Uint 32，从材质直接传递到FGBuffer结构体中，位置位于BasePassPixelShader.usf的InitMooaToonData与InitMooaToonContext，其他可能位置位于GBufferHelpers.ush的GBufferPostDecode()、DeferredShadingCommon.ush的DecodeGBufferData())
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- R（8+8）：SpecularColor.x + SpecularColor.y
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- G（8+6+6）：SpecularColor.z + ReflectionIntensity + HairShadowIntensity
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- B（8+8+6）：SpecularThreshold + SpecularFeather + RimLightIntensity
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- A（6+6+6）：RimLightWidth + RimLightAngle + RimLightDepthThreshold(6)
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- MooaToonDataC(**GBufferD CustomData**) = MainLightShadowColor(8 8 8) + MainLightShadowValueOffset(8)
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# LightModel
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```c++
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/* ================================== Mooa Toon Deferred Lighting Model ======================================================================================================
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* IndirectColor (DiffuseIndirectComposite.usf) = IndirectDiffuse + IndirectSpecular
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* DirectionalLightShadingColor (DeferredLightPixelShaders.usf) = (lerp(ShadowColor, Diffuse * LightColor, min(ShadowValue, LightAttenuation)) + Specular * LightColor) * MooaExposure
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* OtherLightShadingColor (DeferredLightPixelShaders.usf) = (Diffuse + Specular) * LightColor * min(ShadowValue, LightAttenuation) * OtherLightCount
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* FinalColor = IndirectColor + DirectionalLightShadingColor + OtherLightShadingColor
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* ==================================================================================================================================================================
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*/
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// Mooa Indirect Lighting
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if (Material.GBufferData.ShadingModelID == SHADINGMODELID_TOON)
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{
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float3 SHDiffuseAverage = GetSkySHDiffuse(0.0f) * View.SkyLightColor.rgb * View.PreExposure;
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float3 LumenGiDiffuse = IndirectLighting.Diffuse;
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FMooaToonData MooaToonData = Material.GBufferData.MooaToonContext.MooaToonData;
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OutAddColor.rgb = //MooaToonData.MainLightShadowColor +
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lerp(SHDiffuseAverage * Material.GBufferData.BaseColor, LumenGiDiffuse, MooaToonData.GlobalIlluminationDirectionality) * MooaToonData.GlobalIlluminationIntensity;
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OutAddColor.rgb += IndirectLighting.Specular * Pow2(MooaToonData.ReflectionIntensity);
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OutAddColor.rgb *= View.MooaExposureScale;
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OutAddColor.a = Luminance(OutAddColor.rgb);
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}
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else
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{
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IndirectLighting.Specular *= GetSSSCheckerboadSpecularScale(PixelPos, Material.bNeedsSeparateLightAccumulation);
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FLightAccumulator LightAccumulator = (FLightAccumulator)0;
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LightAccumulator_Add(
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LightAccumulator,
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IndirectLighting.Diffuse + IndirectLighting.Specular,
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IndirectLighting.Diffuse,
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1.0f,
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Material.bNeedsSeparateLightAccumulation);
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OutAddColor = LightAccumulator_GetResult(LightAccumulator);
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}
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``` |