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BlueRoseNote/03-UnrealEngine/卡通渲染相关资料/演讲笔记/JasonMa/JasonMa渲染方案分析.md

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JasonMa渲染方案分析 2024-01-25 16:02:26 ⭐

前言

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。

修改内容：

  • GBufferPostDecode.ush：在GBufferPostDecode中给FGBufferData添加InitMooaToonContext()逻辑
  • 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。
  • 其他：
    • MaterialBaking：ExportMaterialProxy.h
    • MaterialEditor：MaterialEditor.cpp
    • PixelInspector：PixelInspectorResult.cpp、PixelInspectorResult.h

ToonShadingCommon.ush

除了一下工具函数，主要实现：

  1. GBuffer的一些Encode / Decode Helper函数。
  2. 用于存储数据的struct FMooaToonData、FMooaToonContext。
  3. 针对上面2个结构体编码与解码的函数。FMooaCustomPayload用于光追Shader。

数据结构体

struct FMooaToonContext  
{  
    FMooaToonData MooaToonData;  
    bool IsMainLight;  
    float3 LightColor;  
    bool IsEditorPreviewWorldType;  
    float Exposure;  
    uint2 PixelPos; // SVPos.xy  
};

struct FMooaToonData  
{  
    // Diffuse  
    float3 MainLightShadowColor;  
    float MainLightShadowValueOffset;  
    float MainLightShadowApplyLightColor;  
    float OtherLightDiffuseThreshold;  
    float OtherLightDiffuseFeather;  
    float GlobalIlluminationIntensity;  
    float GlobalIlluminationDirectionality;  
  
    // Specular  
    float3 SpecularColor;  
    float SpecularThreshold;  
    float SpecularFeather;  
    float ReflectionIntensity;  
    bool IsPBRSpecular;  
    float RimLightIntensity;  
    float RimLightWidth;  
    float RimLightAngle;  
    float RimLightDepthThreshold;   
    // Ray Tracing Shadow  
    uint Stencil;  
    uint RayTracingShadowFlag;  
    float HairShadowWidth;  
    float HairShadowIntensity;  
  
    // Unused  
    float CustomData3;  
};

Encode/Decode

这里推荐使用计算器进行计算更加好理解。

//取得指定Bits位数的最大数值，8位 => 255
uint GetBitsMaxValue(int Bits = 8) {return (1L << Bits) - 1;}  

//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。
uint EncodeUint2ToUint(uint Src1, uint Src2, int BitsSrc1 = 8, int BitsSrc2 = 8)  
{  
	return ((Src1 & GetBitsMaxValue(BitsSrc1)) << BitsSrc2) |  
	(Src2 & GetBitsMaxValue(BitsSrc2));  
}  

//将2个uint合并1个uint后转换成浮点数（0~1）
float EncodeUint2ToFloat(uint Src1, uint Src2, int BitsSrc1 = 8, int BitsSrc2 = 8)  
{  
    return float(EncodeUint2ToUint(Src1, Src2, BitsSrc1, BitsSrc2)) / GetBitsMaxValue(BitsSrc1 + BitsSrc2);  
}  

//将合并后Uint还原成2个uint
void DecodeUint2FromUint(uint Src, out uint Dst1, out uint Dst2, int BitsDst1 = 8, int BitsDst2 = 8)  
{  
    Dst1 = (Src >> BitsDst2)    & GetBitsMaxValue(BitsDst1);  
    Dst2 = Src             & GetBitsMaxValue(BitsDst2);  
}  

//将合并后float（0~1）还原成2个uint
void DecodeUint2FromFloat(float Src, out uint Dst1, out uint Dst2, int BitsDst1 = 8, int BitsDst2 = 8)  
{  
    uint FloatToUint = uint(Src * GetBitsMaxValue(BitsDst1 + BitsDst2));  
    DecodeUint2FromUint(FloatToUint, Dst1, Dst2, BitsDst1, BitsDst2);  
}  
  
//将float（0~1）编码成uint
uint EncodeFloatToUint(float Src1, int BitsSrc1 = 8)  
{  
    return saturate(Src1) * GetBitsMaxValue(BitsSrc1);  
}  

uint EncodeFloat2ToUint(float Src1, float Src2, int BitsSrc1 = 8, int BitsSrc2 = 8)  
{  
    return EncodeUint2ToUint(EncodeFloatToUint(Src1, BitsSrc1), EncodeFloatToUint(Src2, BitsSrc2), BitsSrc1, BitsSrc2);  
}  
  
float EncodeFloat2ToFloat(float Src1, float Src2, int BitsSrc1 = 8, int BitsSrc2 = 8)  
{  
    return EncodeUint2ToFloat(EncodeFloatToUint(Src1, BitsSrc1), EncodeFloatToUint(Src2, BitsSrc2), BitsSrc1, BitsSrc2);  
}

//将uint还原成float（0~1）
float DecodeFloatFromUint(uint Src, int BitsDst1 = 8)  
{  
    return float(Src & GetBitsMaxValue(BitsDst1)) / GetBitsMaxValue(BitsDst1);  
}  
  
void DecodeFloat2FromUint(uint Src, out float Dst1, out float Dst2, int BitsDst1 = 8, int BitsDst2 = 8)  
{  
    uint OutUint1, OutUint2;  
    DecodeUint2FromUint(Src, OutUint1, OutUint2, BitsDst1, BitsDst2);  
    Dst1 = DecodeFloatFromUint(OutUint1, BitsDst1);  
    Dst2 = DecodeFloatFromUint(OutUint2, BitsDst2);  
}  
  
void DecodeFloat2FromFloat(float Src, out float Dst1, out float Dst2, int BitsDst1 = 8, int BitsDst2 = 8)  
{  
    uint OutUint1, OutUint2;  
    DecodeUint2FromFloat(Src, OutUint1, OutUint2, BitsDst1, BitsDst2);  
    Dst1 = DecodeFloatFromUint(OutUint1, BitsDst1);  
    Dst2 = DecodeFloatFromUint(OutUint2, BitsDst2);

结构体与GBuffer Encode/Decode

void EncodeMooaToonData(FMooaToonData MooaToonData, out float4 MooaToonDataA, out float4 MooaToonDataB, out float4 MooaToonDataC)  
{  
    MooaToonDataA = (float4)0;  
    MooaToonDataB = (float4)0;  
    MooaToonDataC = (float4)0;  
  
    MooaToonDataA.x = EncodeFloat2ToUint(MooaToonData.OtherLightDiffuseThreshold, MooaToonData.OtherLightDiffuseFeather);  
    MooaToonDataA.y = EncodeFloat2ToUint(MooaToonData.GlobalIlluminationIntensity, MooaToonData.GlobalIlluminationDirectionality, 6, 6);  
    MooaToonDataA.z = EncodeFloat2ToUint(MooaToonData.MainLightShadowApplyLightColor, MooaToonData.CustomData3, 6, 4);  
    MooaToonDataA.w = EncodeUint2ToUint(  
       EncodeFloatToUint(MooaToonData.HairShadowWidth, 6),  
          EncodeUint2ToUint(  
             MooaToonData.Stencil,  
             EncodeUint2ToUint(MooaToonData.RayTracingShadowFlag, MooaToonData.IsPBRSpecular ? 1 : 0, 2, 1),  
             5, 3),  
          6, 8);  
  
    MooaToonDataB.x = EncodeFloat2ToUint(MooaToonData.SpecularColor.r, MooaToonData.SpecularColor.g);  
    MooaToonDataB.y = EncodeUint2ToUint(  
       EncodeFloatToUint(MooaToonData.SpecularColor.b),  
       EncodeFloat2ToUint(MooaToonData.ReflectionIntensity, MooaToonData.HairShadowIntensity, 6, 6),  
       8, 12);  
    MooaToonDataB.z = EncodeUint2ToUint(  
       EncodeFloat2ToUint(MooaToonData.SpecularThreshold, MooaToonData.SpecularFeather),  
       EncodeFloatToUint(MooaToonData.RimLightIntensity, 6),  
       16, 6);  
    MooaToonDataB.w = EncodeUint2ToUint(  
       EncodeFloat2ToUint(MooaToonData.RimLightWidth, MooaToonData.RimLightAngle, 6, 6),  
       EncodeFloatToUint(MooaToonData.RimLightDepthThreshold, 6),  
       12, 6);  
  
    MooaToonDataC.rgb = saturate(MooaToonData.MainLightShadowColor);  
    MooaToonDataC.a = saturate(MooaToonData.MainLightShadowValueOffset);  
}  
  
FMooaToonData DecodeMooaToonData(float4 MooaToonDataA, float4 MooaToonDataB, float4 MooaToonDataC)  
{  
    FMooaToonData MooaToonData = (FMooaToonData)0;  
    uint Out0, Out1, Out2, Out3;  
    DecodeFloat2FromUint(MooaToonDataA.x, MooaToonData.OtherLightDiffuseThreshold, MooaToonData.OtherLightDiffuseFeather);  
    DecodeFloat2FromUint(MooaToonDataA.y, MooaToonData.GlobalIlluminationIntensity, MooaToonData.GlobalIlluminationDirectionality, 6, 6);  
    DecodeFloat2FromUint(MooaToonDataA.z, MooaToonData.MainLightShadowApplyLightColor, MooaToonData.CustomData3, 6, 4);  
    DecodeUint2FromUint(MooaToonDataA.w, Out0, Out1, 6, 8);  
    MooaToonData.HairShadowWidth = DecodeFloatFromUint(Out0, 6);  
    DecodeUint2FromUint(Out1, MooaToonData.Stencil, Out2, 5, 3);  
    DecodeUint2FromUint(Out2, MooaToonData.RayTracingShadowFlag, MooaToonData.IsPBRSpecular, 2, 1);  
  
    DecodeFloat2FromUint(MooaToonDataB.x, MooaToonData.SpecularColor.r, MooaToonData.SpecularColor.g);  
    DecodeUint2FromUint(MooaToonDataB.y, Out0, Out1, 8, 12);  
    MooaToonData.SpecularColor.b = DecodeFloatFromUint(Out0);  
    DecodeFloat2FromUint(Out1, MooaToonData.ReflectionIntensity, MooaToonData.HairShadowIntensity, 6, 6);  
  
    DecodeUint2FromUint(MooaToonDataB.z, Out0, Out1, 16, 6);  
    DecodeFloat2FromUint(Out0, MooaToonData.SpecularThreshold, MooaToonData.SpecularFeather);  
    MooaToonData.RimLightIntensity = DecodeFloatFromUint(Out1, 6);  
    DecodeUint2FromUint(MooaToonDataB.w, Out0, Out1, 12, 6);  
    DecodeFloat2FromUint(Out0, MooaToonData.RimLightWidth, MooaToonData.RimLightAngle, 6, 6);  
    MooaToonData.RimLightDepthThreshold = DecodeFloatFromUint(Out1, 6);  
  
    MooaToonData.MainLightShadowColor = MooaToonDataC.rgb;  
    MooaToonData.MainLightShadowValueOffset = MooaToonDataC.a;  
  
    return MooaToonData;  
}  
  
uint4 EncodeMooaToonDataToBuffer(FMooaToonData MooaToonData)  
{  
    MooaToonData.SpecularColor = LinearToSrgb(saturate(MooaToonData.SpecularColor));  
  
    float4 MooaToonDataA, MooaToonDataB, MooaToonDataC;  
    uint4 Out;  
    EncodeMooaToonData(MooaToonData, MooaToonDataA, MooaToonDataB, MooaToonDataC);  
    Out.x = EncodeUint2ToUint(MooaToonDataA.x, MooaToonDataB.x, 16, 16);  
    Out.y = EncodeUint2ToUint(MooaToonDataA.y, MooaToonDataB.y, 12, 20);  
    Out.z = EncodeUint2ToUint(MooaToonDataA.z, MooaToonDataB.z, 10, 22);  
    Out.w = EncodeUint2ToUint(MooaToonDataA.w, MooaToonDataB.w, 14, 18);  
  
    return Out;  
}  
  
FMooaToonData DecodeMooaToonDataFromBuffer(uint4 ToonBufferA, float4 CustomData)  
{  
    uint4 Out0, Out1;  
    DecodeUint2FromUint(ToonBufferA.x, Out0.x, Out1.x, 16, 16);  
    DecodeUint2FromUint(ToonBufferA.y, Out0.y, Out1.y, 12, 20);  
    DecodeUint2FromUint(ToonBufferA.z, Out0.z, Out1.z, 10, 22);  
    DecodeUint2FromUint(ToonBufferA.w, Out0.w, Out1.w, 14, 18);  
    float4 MooaToonDataA = Out0;  
    float4 MooaToonDataB = Out1;  
    FMooaToonData MooaToonData = DecodeMooaToonData(MooaToonDataA, MooaToonDataB, CustomData);  
    MooaToonData.MainLightShadowColor = sRGBToLinear(MooaToonData.MainLightShadowColor);  
    MooaToonData.SpecularColor = sRGBToLinear(MooaToonData.SpecularColor);  
    return MooaToonData;  
}

BasePassPixelShader.usf

GBuffer

/*
 * CustomData (GBufferD) (MP_MooaToonDataC) (0~1) = MainLightShadowColor(8 8 8)	 MainLightShadowValueOffset(8)
 * 
 * ToonBufferA (RGBA Uint 32)
 * xyzw: MooaToonDataA.xyzw	| MooaToonDataB.xyzw (32 bits total)
 * 
 * MP_MooaToonDataA (float4, max storage 23 bits uint)
 * x: OtherLightDiffuseThreshold(8)		OtherLightDiffuseFeather(8)
 * y: GlobalIlluminationIntensity(6)	GlobalIlluminationDirectionality(6)
 * z: MainLightShadowApplyLightColor(6)	CustomData3(4)
 * w: HairShadowWidth(6)	Stencil(5)	RayTracingShadowFlag(2)	IsPBRSpecular(1)
 * 
 * MP_MooaToonDataB (float4, max storage 23 bits uint)
 * x: SpecularColor.x(8)		SpecularColor.y(8)
 * y: SpecularColor.z(8)		ReflectionIntensity(6)		HairShadowIntensity(6)
 * z: SpecularThreshold(8)		SpecularFeather(8)			RimLightIntensity(6)
 * w: RimLightWidth(6)			RimLightAngle(6)			RimLightDepthThreshold(6)
 * 
 * 
 * Tips: store sRGB Color to maximize accuracy
 */

PS.float4, max storage 23 bits uint Jason自己添加了GBT_Uint_32_32_32_32的GBuffer格式。

  • MooaToonDataA (RGBA Uint 32 ToonBufferA)
    • R（4+4）：OtherLightDiffuseThreshold + OtherLightDiffuseFeather
    • G（4+4）：GlobalIlluminationIntensity + GlobalIlluminationDirectionality
    • B（4+4）：MainLightShadowApplyLightColor + CustomData3
    • A （6+5+2+1）：HairShadowWidth + Stencil + RayTracingShadowFlag + IsPBRSpecular
  • 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())
    • R（8+8）：SpecularColor.x + SpecularColor.y
    • G（8+6+6）：SpecularColor.z + ReflectionIntensity + HairShadowIntensity
    • B（8+8+6）：SpecularThreshold + SpecularFeather + RimLightIntensity
    • A（6+6+6）：RimLightWidth + RimLightAngle + RimLightDepthThreshold(6)
  • MooaToonDataC(GBufferD CustomData) = MainLightShadowColor(8 8 8) + MainLightShadowValueOffset(8)

LightModel

/* ================================== Mooa Toon Deferred Lighting Model ======================================================================================================  
 * IndirectColor                (DiffuseIndirectComposite.usf)    = IndirectDiffuse + IndirectSpecular  
 * DirectionalLightShadingColor (DeferredLightPixelShaders.usf)    = (lerp(ShadowColor, Diffuse * LightColor, min(ShadowValue, LightAttenuation)) + Specular * LightColor) * MooaExposure  
 * OtherLightShadingColor        (DeferredLightPixelShaders.usf)    = (Diffuse + Specular) * LightColor * min(ShadowValue, LightAttenuation) * OtherLightCount  
 * FinalColor                                                    = IndirectColor + DirectionalLightShadingColor + OtherLightShadingColor  
 * ==================================================================================================================================================================  
 */
 // Mooa Indirect Lighting  
if (Material.GBufferData.ShadingModelID == SHADINGMODELID_TOON)  
{  
	float3 SHDiffuseAverage = GetSkySHDiffuse(0.0f) * View.SkyLightColor.rgb * View.PreExposure;  
	float3 LumenGiDiffuse = IndirectLighting.Diffuse;  
	FMooaToonData MooaToonData = Material.GBufferData.MooaToonContext.MooaToonData;  
	OutAddColor.rgb = //MooaToonData.MainLightShadowColor +  
		lerp(SHDiffuseAverage * Material.GBufferData.BaseColor, LumenGiDiffuse, MooaToonData.GlobalIlluminationDirectionality) * MooaToonData.GlobalIlluminationIntensity;  
	OutAddColor.rgb += IndirectLighting.Specular * Pow2(MooaToonData.ReflectionIntensity);  
	OutAddColor.rgb *= View.MooaExposureScale;  
	OutAddColor.a = Luminance(OutAddColor.rgb);  
}  
else  
{  
	IndirectLighting.Specular *= GetSSSCheckerboadSpecularScale(PixelPos, Material.bNeedsSeparateLightAccumulation);  
	FLightAccumulator LightAccumulator = (FLightAccumulator)0;  
	LightAccumulator_Add(  
		LightAccumulator,  
		IndirectLighting.Diffuse + IndirectLighting.Specular,  
		IndirectLighting.Diffuse,  
		1.0f,  
		Material.bNeedsSeparateLightAccumulation);  
	OutAddColor = LightAccumulator_GetResult(LightAccumulator);  
}