Sebastien Lagarde
6 年前
当前提交
162b8ee9
共有 6 个文件被更改，包括 252 次插入 和 211 次删除
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10com.unity.render-pipelines.core/CoreRP/ShaderLibrary/CommonMaterial.hlsl
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244com.unity.render-pipelines.high-definition/HDRP/Material/Lit/Lit.hlsl
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7com.unity.render-pipelines.high-definition/HDRP/Material/StackLit/StackLit.hlsl
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4com.unity.render-pipelines.high-definition/HDRP/Material/SubsurfaceScattering/SubsurfaceScattering.hlsl
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189com.unity.render-pipelines.high-definition/HDRP/Material/SubsurfaceScattering/SubsurfaceScatteringUtils.hlsl
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9com.unity.render-pipelines.high-definition/HDRP/Material/SubsurfaceScattering/SubsurfaceScatteringUtils.hlsl.meta
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// This must be include after SubsurfaceScattering.hlsl |
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// This files include various helper function to easily setup SSS and transmission inside a material. It require that the material follow naming convention |
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// User can request either SSS function, or Transmission, or both, they need to define INCLUDE_SUBSURFACESCATTERING and/or INCLUDE_TRANSMISSION |
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// And define the lighting model to use for transmission. By default it is Lambert. For Disney: TRANSMISSION_DISNEY_DIFFUSE_BRDF |
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// Also user need to be sure that upper 16bit of bsdfData.materialFeatures are not used |
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// Additional bits set in 'bsdfData.materialFeatures' to save registers and simplify feature tracking. |
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#define MATERIAL_FEATURE_SSS_TRANSMISSION_START (1 << 16) // It should be safe to start these flags |
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#define MATERIAL_FEATURE_FLAGS_SSS_OUTPUT_SPLIT_LIGHTING ((MATERIAL_FEATURE_SSS_TRANSMISSION_START) << 0) |
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#define MATERIAL_FEATURE_FLAGS_SSS_TEXTURING_MODE_OFFSET FastLog2((MATERIAL_FEATURE_SSS_TRANSMISSION_START) << 1) // 2 bits |
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#define MATERIAL_FEATURE_FLAGS_TRANSMISSION_MODE_MIXED_THICKNESS ((MATERIAL_FEATURE_SSS_TRANSMISSION_START) << 3) |
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// Flags used as a shortcut to know if we have thin mode transmission |
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#define MATERIAL_FEATURE_FLAGS_TRANSMISSION_MODE_THIN_THICKNESS ((MATERIAL_FEATURE_SSS_TRANSMISSION_START) << 4) |
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#ifdef INCLUDE_SUBSURFACESCATTERING |
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// Assume that bsdfData.diffusionProfile is init |
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void FillMaterialSSS(uint diffusionProfile, float subsurfaceMask, inout BSDFData bsdfData) |
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{ |
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bsdfData.diffusionProfile = diffusionProfile; |
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bsdfData.fresnel0 = _TransmissionTintsAndFresnel0[diffusionProfile].a; |
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bsdfData.subsurfaceMask = subsurfaceMask; |
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bsdfData.materialFeatures |= MATERIAL_FEATURE_FLAGS_SSS_OUTPUT_SPLIT_LIGHTING; |
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bsdfData.materialFeatures |= GetSubsurfaceScatteringTexturingMode(bsdfData.diffusionProfile) << MATERIAL_FEATURE_FLAGS_SSS_TEXTURING_MODE_OFFSET; |
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} |
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bool ShouldOutputSplitLighting(BSDFData bsdfData) |
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{ |
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return HasFeatureFlag(bsdfData.materialFeatures, MATERIAL_FEATURE_FLAGS_SSS_OUTPUT_SPLIT_LIGHTING); |
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} |
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float3 SSSGetModifiedDiffuseColor(BSDFData bsdfData) |
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{ |
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// Subsurface scattering mdoe |
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uint texturingMode = (bsdfData.materialFeatures >> MATERIAL_FEATURE_FLAGS_SSS_TEXTURING_MODE_OFFSET) & 3; |
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return ApplySubsurfaceScatteringTexturingMode(texturingMode, bsdfData.diffuseColor); |
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} |
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#endif |
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#ifdef INCLUDE_TRANSMISSION |
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// Assume that bsdfData.diffusionProfile is init |
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void FillMaterialTransmission(uint diffusionProfile, float thickness, inout BSDFData bsdfData) |
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{ |
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bsdfData.diffusionProfile = diffusionProfile; |
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bsdfData.fresnel0 = _TransmissionTintsAndFresnel0[diffusionProfile].a; |
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bsdfData.thickness = _ThicknessRemaps[diffusionProfile].x + _ThicknessRemaps[diffusionProfile].y * thickness; |
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// The difference between the thin and the regular (a.k.a. auto-thickness) modes is the following: |
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// * in the thin object mode, we assume that the geometry is thin enough for us to safely share |
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// the shadowing information between the front and the back faces; |
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// * the thin mode uses baked (textured) thickness for all transmission calculations; |
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// * the thin mode uses wrapped diffuse lighting for the NdotL; |
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// * the auto-thickness mode uses the baked (textured) thickness to compute transmission from |
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// indirect lighting and non-shadow-casting lights; for shadowed lights, it calculates |
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// the thickness using the distance to the closest occluder sampled from the shadow map. |
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// If the distance is large, it may indicate that the closest occluder is not the back face of |
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// the current object. That's not a problem, since large thickness will result in low intensity. |
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bool useThinObjectMode = IsBitSet(asuint(_TransmissionFlags), diffusionProfile); |
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bsdfData.materialFeatures |= useThinObjectMode ? MATERIAL_FEATURE_FLAGS_TRANSMISSION_MODE_THIN_THICKNESS : MATERIAL_FEATURE_FLAGS_TRANSMISSION_MODE_MIXED_THICKNESS; |
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// Compute transmittance using baked thickness here. It may be overridden for direct lighting |
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// in the auto-thickness mode (but is always used for indirect lighting). |
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#if SHADEROPTIONS_USE_DISNEY_SSS |
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bsdfData.transmittance = ComputeTransmittanceDisney(_ShapeParams[diffusionProfile].rgb, |
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_TransmissionTintsAndFresnel0[diffusionProfile].rgb, |
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bsdfData.thickness); |
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#else |
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bsdfData.transmittance = ComputeTransmittanceJimenez(_HalfRcpVariancesAndWeights[diffusionProfile][0].rgb, |
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_HalfRcpVariancesAndWeights[diffusionProfile][0].a, |
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_HalfRcpVariancesAndWeights[diffusionProfile][1].rgb, |
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_HalfRcpVariancesAndWeights[diffusionProfile][1].a, |
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_TransmissionTintsAndFresnel0[diffusionProfile].rgb, |
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bsdfData.thickness); |
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#endif |
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} |
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#ifdef HAS_LIGHTLOOP |
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#define SSS_WRAP_ANGLE (PI/12) // 15 degrees |
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#define SSS_WRAP_LIGHT cos(PI/2 - SSS_WRAP_ANGLE) |
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// Currently, we only model diffuse transmission. Specular transmission is not yet supported. |
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// Transmitted lighting is computed as follows: |
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// - we assume that the object is a thick plane (slab); |
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// - we reverse the front-facing normal for the back of the object; |
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// - we assume that the incoming radiance is constant along the entire back surface; |
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// - we apply BSDF-specific diffuse transmission to transmit the light subsurface and back; |
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// - we integrate the diffuse reflectance profile w.r.t. the radius (while also accounting |
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// for the thickness) to compute the transmittance; |
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// - we multiply the transmitted radiance by the transmittance. |
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float3 EvaluateTransmission(BSDFData bsdfData, float3 transmittance, float NdotL, float NdotV, float LdotV, float attenuation) |
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{ |
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// Apply wrapped lighting to better handle thin objects at grazing angles. |
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float wrappedNdotL = ComputeWrappedDiffuseLighting(-NdotL, SSS_WRAP_LIGHT); |
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// Apply BSDF-specific diffuse transmission to attenuation. See also: [SSS-NOTE-TRSM] |
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// We don't multiply by 'bsdfData.diffuseColor' here. It's done only once in PostEvaluateBSDF(). |
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#ifdef TRANSMISSION_DISNEY_DIFFUSE_BRDF |
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attenuation *= DisneyDiffuse(NdotV, max(0, -NdotL), LdotV, bsdfData.perceptualRoughness); |
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#else |
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attenuation *= Lambert(); |
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#endif |
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float intensity = attenuation * wrappedNdotL; |
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return intensity * transmittance; |
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} |
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void PreEvaluateLightTransmission(float NdotL, BSDFData bsdfData, inout float3 normalWS, inout float contactShadowIndex) |
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{ |
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// When using thin transmission mode we don't fetch shadow map for back face, we reuse front face shadow |
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// However we flip the normal for the bias (and the NdotL test) and disable contact shadow |
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if (HasFeatureFlag(bsdfData.materialFeatures, MATERIAL_FEATURE_FLAGS_TRANSMISSION_MODE_THIN_THICKNESS) && NdotL < 0) |
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{ |
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// Disable shadow contact in case of transmission and backface shadow |
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normalWS = -normalWS; |
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contactShadowIndex = -1; |
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} |
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} |
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float3 PostEvaluateLightTransmission( ShadowContext shadowContext, PositionInputs posInput, float distFrontFaceToLight, |
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float NdotL, float NdotV, float LdotV, float3 L, float attenuation, LightData lightData, BSDFData bsdfData) |
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{ |
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float3 transmittance = bsdfData.transmittance; |
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// Note that if NdotL is positive, we have one fetch on front face done by EvaluateLight_Punctual, otherwise we have only one fetch |
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// done by transmission code here (EvaluateLight_Punctual discard the fetch if NdotL < 0) |
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bool mixedThicknessMode = HasFeatureFlag(bsdfData.materialFeatures, MATERIAL_FEATURE_FLAGS_TRANSMISSION_MODE_MIXED_THICKNESS) |
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&& NdotL < 0 && lightData.shadowIndex >= 0; |
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if (mixedThicknessMode) |
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{ |
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// Recompute transmittance using the thickness value computed from the shadow map. |
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// Compute the distance from the light to the back face of the object along the light direction. |
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float distBackFaceToLight = GetPunctualShadowClosestDistance(shadowContext, s_linear_clamp_sampler, |
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posInput.positionWS, lightData.shadowIndex, L, lightData.positionWS); |
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// Our subsurface scattering models use the semi-infinite planar slab assumption. |
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// Therefore, we need to find the thickness along the normal. |
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float thicknessInUnits = (distFrontFaceToLight - distBackFaceToLight) * -NdotL; |
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float thicknessInMeters = thicknessInUnits * _WorldScales[bsdfData.diffusionProfile].x; |
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float thicknessInMillimeters = thicknessInMeters * MILLIMETERS_PER_METER; |
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#if SHADEROPTIONS_USE_DISNEY_SSS |
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// We need to make sure it's not less than the baked thickness to minimize light leaking. |
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float thicknessDelta = max(0, thicknessInMillimeters - bsdfData.thickness); |
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float3 S = _ShapeParams[bsdfData.diffusionProfile].rgb; |
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// Approximate the decrease of transmittance by e^(-1/3 * dt * S). |
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#if 0 |
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float3 expOneThird = exp(((-1.0 / 3.0) * thicknessDelta) * S); |
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#else |
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// Help the compiler. |
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float k = (-1.0 / 3.0) * LOG2_E; |
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float3 p = (k * thicknessDelta) * S; |
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float3 expOneThird = exp2(p); |
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#endif |
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transmittance *= expOneThird; |
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#else // SHADEROPTIONS_USE_DISNEY_SSS |
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// We need to make sure it's not less than the baked thickness to minimize light leaking. |
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thicknessInMillimeters = max(thicknessInMillimeters, bsdfData.thickness); |
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transmittance = ComputeTransmittanceJimenez(_HalfRcpVariancesAndWeights[bsdfData.diffusionProfile][0].rgb, |
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_HalfRcpVariancesAndWeights[bsdfData.diffusionProfile][0].a, |
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_HalfRcpVariancesAndWeights[bsdfData.diffusionProfile][1].rgb, |
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_HalfRcpVariancesAndWeights[bsdfData.diffusionProfile][1].a, |
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_TransmissionTintsAndFresnel0[bsdfData.diffusionProfile].rgb, |
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thicknessInMillimeters); |
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#endif // SHADEROPTIONS_USE_DISNEY_SSS |
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} |
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// Note: we do not modify the distance to the light, or the light angle for the back face. |
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// This is a performance-saving optimization which makes sense as long as the thickness is small. |
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return EvaluateTransmission(bsdfData, transmittance, NdotL, NdotV, LdotV, attenuation); |
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} |
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#endif // HAS_LIGHTLOOP |
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#endif |
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fileFormatVersion: 2 |
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guid: 599608ec6436ae244a53c032ec1b96fe |
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ShaderImporter: |
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externalObjects: {} |
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defaultTextures: [] |
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nonModifiableTextures: [] |
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userData: |
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assetBundleName: |
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assetBundleVariant: |
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