Merge branch 'xbei/subsurface_scattering_nee' into 'main'

[REMIX-2184] Implement direct light support for thin opaque

See merge request lightspeedrtx/dxvk-remix-nv!542

src/dxvk/rtx_render/rtx_restir_gi_rayquery.cpp

@@ -75,6 +75,7 @@ namespace dxvk {
         TEXTURE2D(RESTIR_GI_REUSE_BINDING_HIT_GEOMETRY_INPUT)
         TEXTURE2D(RESTIR_GI_REUSE_BINDING_POSITION_ERROR_INPUT)
         TEXTURE2D(RESTIR_GI_REUSE_BINDING_SHARED_FLAGS_INPUT)
+        TEXTURE2D(RESTIR_GI_REUSE_BINDING_SHARED_SURFACE_INDEX_INPUT)
         RW_TEXTURE2D(RESTIR_GI_REUSE_BINDING_LAST_GBUFFER)
       END_PARAMETER()
     };
@@ -107,6 +108,7 @@ namespace dxvk {
         TEXTURE2D(RESTIR_GI_REUSE_BINDING_HIT_GEOMETRY_INPUT)
         TEXTURE2D(RESTIR_GI_REUSE_BINDING_POSITION_ERROR_INPUT)
         TEXTURE2D(RESTIR_GI_REUSE_BINDING_SHARED_FLAGS_INPUT)
+        TEXTURE2D(RESTIR_GI_REUSE_BINDING_SHARED_SURFACE_INDEX_INPUT)
         RW_TEXTURE2D(RESTIR_GI_REUSE_BINDING_LAST_GBUFFER)
       END_PARAMETER()
     };
@@ -218,6 +220,7 @@ namespace dxvk {
       ctx->bindResourceView(RESTIR_GI_REUSE_BINDING_RADIANCE_INPUT, rtOutput.m_restirGIRadiance.view(Resources::AccessType::Read), nullptr);
       ctx->bindResourceView(RESTIR_GI_REUSE_BINDING_HIT_GEOMETRY_INPUT, rtOutput.m_restirGIHitGeometry.view, nullptr);
       ctx->bindResourceView(RESTIR_GI_REUSE_BINDING_POSITION_ERROR_INPUT, rtOutput.m_primaryPositionError.view, nullptr);
+      ctx->bindResourceView(RESTIR_GI_REUSE_BINDING_SHARED_SURFACE_INDEX_INPUT, rtOutput.m_sharedSurfaceIndex.view, nullptr);
       ctx->bindResourceView(RESTIR_GI_REUSE_BINDING_SHARED_FLAGS_INPUT, rtOutput.m_sharedFlags.view, nullptr);
 
       ctx->bindShader(VK_SHADER_STAGE_COMPUTE_BIT, ReSTIRGITemporalReuseShader::getShader());
@@ -242,6 +245,7 @@ namespace dxvk {
       ctx->bindResourceView(RESTIR_GI_REUSE_BINDING_RADIANCE_INPUT, rtOutput.m_restirGIRadiance.view(Resources::AccessType::Read), nullptr);
       ctx->bindResourceView(RESTIR_GI_REUSE_BINDING_HIT_GEOMETRY_INPUT, rtOutput.m_restirGIHitGeometry.view, nullptr);
       ctx->bindResourceView(RESTIR_GI_REUSE_BINDING_POSITION_ERROR_INPUT, rtOutput.m_primaryPositionError.view, nullptr);
+      ctx->bindResourceView(RESTIR_GI_REUSE_BINDING_SHARED_SURFACE_INDEX_INPUT, rtOutput.m_sharedSurfaceIndex.view, nullptr);
       ctx->bindResourceView(RESTIR_GI_REUSE_BINDING_SHARED_FLAGS_INPUT, rtOutput.m_sharedFlags.view, nullptr);
 
       ctx->bindShader(VK_SHADER_STAGE_COMPUTE_BIT, ReSTIRGISpatialReuseShader::getShader());

src/dxvk/rtx_render/rtx_rtxdi_rayquery.cpp

@@ -69,6 +69,7 @@ namespace dxvk {
         TEXTURE2D(RTXDI_REUSE_BINDING_WS_MVEC_INPUT_OUTPUT)
         TEXTURE2D(RTXDI_REUSE_BINDING_SS_MVEC_INPUT)
         TEXTURE2D(RTXDI_REUSE_BINDING_POSITION_ERROR_INPUT)
+        TEXTURE2D(RTXDI_REUSE_BINDING_SHARED_SURFACE_INDEX_INPUT)
         TEXTURE2D(RTXDI_REUSE_BINDING_SHARED_FLAGS_INPUT)
         RW_TEXTURE2D(RTXDI_REUSE_BINDING_LAST_GBUFFER)
         RW_TEXTURE2D(RTXDI_REUSE_BINDING_REPROJECTION_CONFIDENCE_OUTPUT)
@@ -103,6 +104,7 @@ namespace dxvk {
         TEXTURE2D(RTXDI_REUSE_BINDING_WS_MVEC_INPUT_OUTPUT)
         TEXTURE2D(RTXDI_REUSE_BINDING_SS_MVEC_INPUT)
         TEXTURE2D(RTXDI_REUSE_BINDING_POSITION_ERROR_INPUT)
+        TEXTURE2D(RTXDI_REUSE_BINDING_SHARED_SURFACE_INDEX_INPUT)
         TEXTURE2D(RTXDI_REUSE_BINDING_SHARED_FLAGS_INPUT)
         RW_TEXTURE2D(RTXDI_REUSE_BINDING_LAST_GBUFFER)
         RW_TEXTURE2D(RTXDI_REUSE_BINDING_REPROJECTION_CONFIDENCE_OUTPUT)
@@ -253,6 +255,7 @@ namespace dxvk {
       ctx->bindResourceView(RTXDI_REUSE_BINDING_POSITION_ERROR_INPUT, rtOutput.m_primaryPositionError.view, nullptr);
       ctx->bindResourceView(RTXDI_REUSE_BINDING_LAST_GBUFFER, rtOutput.m_gbufferLast.view, nullptr);
       ctx->bindResourceView(RTXDI_REUSE_BINDING_REPROJECTION_CONFIDENCE_OUTPUT, rtOutput.m_reprojectionConfidence.view, nullptr);
+      ctx->bindResourceView(RTXDI_REUSE_BINDING_SHARED_SURFACE_INDEX_INPUT, rtOutput.m_sharedSurfaceIndex.view, nullptr);
       ctx->bindResourceView(RTXDI_REUSE_BINDING_SHARED_FLAGS_INPUT, rtOutput.m_sharedFlags.view, nullptr);
       ctx->bindResourceView(RTXDI_REUSE_BINDING_BSDF_FACTOR_OUTPUT, rtOutput.m_bsdfFactor.view, nullptr);
       ctx->bindResourceView(RTXDI_REUSE_BINDING_TEMPORAL_POSITION_OUTPUT, rtOutput.m_primaryRtxdiTemporalPosition.view, nullptr);
@@ -281,6 +284,7 @@ namespace dxvk {
       ctx->bindResourceView(RTXDI_REUSE_BINDING_POSITION_ERROR_INPUT, rtOutput.m_primaryPositionError.view, nullptr);
       ctx->bindResourceView(RTXDI_REUSE_BINDING_LAST_GBUFFER, rtOutput.m_gbufferLast.view, nullptr);
       ctx->bindResourceView(RTXDI_REUSE_BINDING_REPROJECTION_CONFIDENCE_OUTPUT, rtOutput.m_reprojectionConfidence.view, nullptr);
+      ctx->bindResourceView(RTXDI_REUSE_BINDING_SHARED_SURFACE_INDEX_INPUT, rtOutput.m_sharedSurfaceIndex.view, nullptr);
       ctx->bindResourceView(RTXDI_REUSE_BINDING_SHARED_FLAGS_INPUT, rtOutput.m_sharedFlags.view, nullptr);
       ctx->bindResourceView(RTXDI_REUSE_BINDING_BSDF_FACTOR_OUTPUT, rtOutput.m_bsdfFactor.view, nullptr);
       ctx->bindResourceView(RTXDI_REUSE_BINDING_TEMPORAL_POSITION_OUTPUT, rtOutput.m_primaryRtxdiTemporalPosition.view, nullptr);

src/dxvk/rtx_render/rtx_scene_manager.cpp

@@ -894,9 +894,6 @@ namespace dxvk {
       bool alphaIsThinFilmThickness = false;
       float thinFilmThicknessConstant = 0.0f;
       float displaceIn = 1.0f;
-      float thinOpaqueThickness = 0.0f;
-      float thinOpaqueAttenuationCoefficient = 0.0f;
-      uint8_t thinOpaqueSingleScatteringAlbedoScale = 0;
 
       Vector3 subsurfaceTransmittanceColor(0.0f, 0.0f, 0.0f);
       float subsurfaceMeasurementDistance = 0.0f;

src/dxvk/shaders/rtx/algorithm/integrator.slangh

@@ -213,6 +213,7 @@ bool evalNEESecondary(
   Ray viewRay,
   MinimalRayInteraction minimalRayInteraction, 
   MinimalSurfaceInteraction minimalSurfaceInteraction,
+  OpaqueSurfaceMaterialInteraction opaqueSurfaceMaterialInteraction,
   inout vec3 diffuseLight,
   inout vec3 specularLight,
   uint16_t surfaceIndex, float2 texcoords)
@@ -223,13 +224,17 @@ bool evalNEESecondary(
   uint8_t rayMask = OBJECT_MASK_OPAQUE | (objectMask & OBJECT_MASK_ALL_DYNAMIC);
   if (cb.enableIndirectTranslucentShadows) rayMask |= OBJECT_MASK_TRANSLUCENT;
 
+  // Load Subsurface Material
+  SubsurfaceMaterial subSurfaceMaterial;
+  const bool isSubSurface = subSurfaceMaterialReadHelper(opaqueSurfaceMaterialInteraction.subsurfaceMaterialIndex, subSurfaceMaterial);
+
   VisibilityResult visibility = traceVisibilityRay(minimalSurfaceInteraction,
-    lightSample.position, false, rayMask,
+    lightSample.position, rayMask,
     visibilityModeEnableTranslucentMaterials,
     sampledTransportPortalIndex, portalSpace,
     minimalRayInteraction.coneRadius, viewRay.spreadAngle, 0.98, isViewModelSurface, false,
-    surfaceIndex, texcoords);
-
+    surfaceIndex, texcoords,
+    isSubSurface, opaqueSurfaceMaterialInteraction.shadingNormal);
 
   if (visibility.hasOpaqueHit)
   {
@@ -259,7 +264,9 @@ void evaluateUnshadowedLight(
   out vec3 diffuseLight,
   out vec3 specularLight)
 {
-  if (dot(inputDirection, opaqueSurfaceMaterialInteraction.shadingNormal) < 0.0)
+  if (dot(inputDirection, opaqueSurfaceMaterialInteraction.shadingNormal) < 0.0 &&
+      (!cb.thinOpaqueEnable ||
+       opaqueSurfaceMaterialInteraction.subsurfaceMaterialIndex == BINDING_INDEX_INVALID))
   {
     diffuseLight = specularLight = 0;
     return;
@@ -268,6 +275,6 @@ void evaluateUnshadowedLight(
   const SurfaceMaterialInteractionSplitWeight splitWeight = opaqueSurfaceMaterialInteractionCalcProjectedWeight(
     opaqueSurfaceMaterialInteraction, minimalRayInteraction, inputDirection);
 
-  diffuseLight = lightSample.radiance * splitWeight.diffuseReflectionWeight;
+  diffuseLight = lightSample.radiance * (splitWeight.diffuseReflectionWeight + splitWeight.diffuseTransmissionWeight);
   specularLight = lightSample.radiance * splitWeight.specularReflectionWeight;
 }

src/dxvk/shaders/rtx/algorithm/integrator_direct.slangh

@@ -51,10 +51,11 @@ void evalNEEPrimary(
   PortalSpace2BitsType portalSpace,
   uint8_t objectMask,
   bool isViewModelSurface,
-  Ray viewRay, 
-  MinimalRayInteraction minimalRayInteraction, 
+  Ray viewRay,
+  MinimalRayInteraction minimalRayInteraction,
   MinimalSurfaceInteraction minimalSurfaceInteraction,
-  OpaqueSurfaceMaterialInteraction opaqueSurfaceMaterialInteraction)
+  OpaqueSurfaceMaterialInteraction opaqueSurfaceMaterialInteraction
+  )
 {
   // Setup and trace the visibility ray
 
@@ -64,19 +65,27 @@ void evalNEEPrimary(
   const bool enablePOM = cb.pomEnableDirectLighting && opaqueSurfaceMaterialInteractionHasHeightTexture(opaqueSurfaceMaterialInteraction);
   const uint16_t primarySurfaceIndex = enablePOM ? uint16_t(SharedSurfaceIndex[pixelCoordinate]) : BINDING_INDEX_INVALID;
 
-  VisibilityResult visibility = traceVisibilityRay(minimalSurfaceInteraction,
-    lightSample.position, false, rayMask,
+  // Load Subsurface Material
+  SubsurfaceMaterial subSurfaceMaterial;
+  const bool isSubSurface = subSurfaceMaterialReadHelper(opaqueSurfaceMaterialInteraction.subsurfaceMaterialIndex, subSurfaceMaterial);
+
+  const VisibilityResult visibility = traceVisibilityRay(
+    minimalSurfaceInteraction,
+    lightSample.position, rayMask,
     visibilityModeAccurateHitDistance | visibilityModeEnableTranslucentMaterials,
     sampledTransportPortalIndex, portalSpace,
     minimalRayInteraction.coneRadius, viewRay.spreadAngle, 1.0, isViewModelSurface, false,
-    primarySurfaceIndex, DisplacementTextureCoord[pixelCoordinate]);
+    primarySurfaceIndex, DisplacementTextureCoord[pixelCoordinate],
+    isSubSurface, opaqueSurfaceMaterialInteraction.shadingNormal);
 
   hitDistance = visibility.hitDistance;
   hasOpaqueHit = visibility.hasOpaqueHit;
   illuminance = 0;
 
   if (visibility.hasOpaqueHit)
+  {
     return;
+  }
 
   // Evaluate the material and accumulate throughput and hit distance
 
@@ -89,16 +98,21 @@ void evalNEEPrimary(
 
   const f16vec3 diffuseLobeWeight = splitWeight.diffuseReflectionWeight;
   const f16vec3 specularLobeWeight = splitWeight.specularReflectionWeight;
+  const f16vec3 diffuseTransmissionLobeWeight = splitWeight.diffuseTransmissionWeight;
+
+  // TODO: Handle Transmission Weight
 
   // Accumulate Radiance
 
   const vec3 commonLightThroughput = lightSampleThroughput * vec3(visibility.attenuation);
   const vec3 diffuseLobeLightThroughput = vec3(diffuseLobeWeight) * commonLightThroughput;
   const vec3 specularLobeLightThroughput = vec3(specularLobeWeight) * commonLightThroughput;
+  const vec3 diffuseTransmissionLobeLightThroughput = vec3(diffuseTransmissionLobeWeight) * commonLightThroughput;
   const vec3 diffuseAttenuatedRadiance = lightSample.radiance * diffuseLobeLightThroughput;
   const vec3 specularAttenuatedRadiance = lightSample.radiance * specularLobeLightThroughput;
+  const vec3 diffuseTransmissionAttenuatedRadiance = lightSample.radiance * diffuseTransmissionLobeLightThroughput;
 
-  diffuseLobeRadiance += throughput * diffuseAttenuatedRadiance;
+  diffuseLobeRadiance += throughput * (diffuseAttenuatedRadiance + diffuseTransmissionAttenuatedRadiance);
   specularLobeRadiance += throughput * specularAttenuatedRadiance;
 
   // Illuminance for RTXDI gradients: just light sample radiance and visibility over sampling PDF
@@ -330,12 +344,13 @@ void integrateDirectPath(
         lightSample, inverseSelectionPdf, lightIdx);
     }
 
-    // Evaluate NEE
+    SubsurfaceMaterial subSurfaceMaterial;
+    const bool sssEnable = subSurfaceMaterialReadHelper(opaqueSurfaceMaterialInteraction.subsurfaceMaterialIndex, subSurfaceMaterial);
 
+    // Evaluate NEE
     if (rtxdiLightSampleValid || risLightSampleValid)
     {
       bool hasOpaqueHit = false;
-
       evalNEEPrimary(
         throughput, pixelCoordinate,
         diffuseLobeRadiance, specularLobeRadiance, lightHitDistance, hasOpaqueHit, illuminance,
@@ -390,7 +405,6 @@ void integrateDirectPath(
 
     directPathTextures.SecondaryCombinedDiffuseLobeRadianceHitDistance[pixelCoordinate] = secondaryCombinedDiffuseLobeRadianceHitDistance;
     directPathTextures.SecondaryCombinedSpecularLobeRadianceHitDistance[pixelCoordinate] = secondaryCombinedSpecularLobeRadianceHitDistance;
-
     directPathTextures.PrimaryRtxdiIlluminance[pixelCoordinate] = 0;
   }
 

src/dxvk/shaders/rtx/algorithm/integrator_indirect.slangh

@@ -597,7 +597,7 @@ void integratePathVertex(
         // Todo: Ray Portal transport sampling in the future.
         evalNEESecondary(
           lightSample, invalidRayPortalIndex, pathState.portalSpace, pathState.rayMask,
-          isViewModel, ray, rayInteraction, surfaceInteraction,
+          isViewModel, ray, rayInteraction, surfaceInteraction, opaqueSurfaceMaterialInteraction,
           diffuseLight, specularLight, surfaceIndex, surfaceInteraction.textureCoordinates);
 
         // Create a NEE Cache task for lights with non-zero contributions.
@@ -728,7 +728,7 @@ void integratePathVertex(
             minimalRayInteraction2.viewDirection = -incomingDirection;
             vec3 L2 = normalize(spatialReservoir.position - surfaceInteraction.position);
             SurfaceMaterialInteractionSplitWeight brdf2 = opaqueSurfaceMaterialInteractionCalcProjectedWeight(opaqueSurfaceMaterialInteraction, minimalRayInteraction2, L2);
-            indirectLight += spatialReservoir.radiance * brdf2.diffuseReflectionWeight * spatialReservoir.avgWeight;        
+            indirectLight += spatialReservoir.radiance * (brdf2.diffuseReflectionWeight + brdf2.diffuseTransmissionWeight) * spatialReservoir.avgWeight;        
             if (opaqueSurfaceMaterialInteraction.isotropicRoughness > RAB_RESTIR_GI_MIN_ROUGHNESS)
             {
               indirectLight += spatialReservoir.radiance * brdf2.specularReflectionWeight * spatialReservoir.avgWeight;

src/dxvk/shaders/rtx/algorithm/lighting.slangh

@@ -76,6 +76,7 @@ bool sampleLightRTXDI(
 bool sampleLightBasicRIS(
   inout RNG randomState,
   MinimalSurfaceInteraction surfaceInteraction,
+  OpaqueSurfaceMaterialInteraction opaqueSurfaceMaterialInteraction,
   inout LightSample lightSample, inout float inverseSelectionPdf)
 {
   if (cb.risTotalSampleCount == 0)
@@ -89,6 +90,10 @@ bool sampleLightBasicRIS(
   float selectedLightTargetPdf = 0.0f;
   float weightSum = 0.0f;
 
+    // Load Subsurface Material
+  SubsurfaceMaterial subSurfaceMaterial;
+  const bool isSubSurface = subSurfaceMaterialReadHelper(opaqueSurfaceMaterialInteraction.subsurfaceMaterialIndex, subSurfaceMaterial);
+
   [unroll]
   for (uint lightType = 0; lightType < lightTypeCount; ++lightType)
   {
@@ -118,7 +123,7 @@ bool sampleLightBasicRIS(
       // can effectively unroll the loop and remove the switch from decodedPolymorphicLightCalcWeight
       DecodedPolymorphicLight decodedPolymorphicLight = decodePolymorphicLight(memoryPolymorphicLight);
       decodedPolymorphicLight.polymorphicType = lightType;
-      const float targetPdf = decodedPolymorphicLightCalcWeight(decodedPolymorphicLight, surfaceInteraction);
+      const float targetPdf = decodedPolymorphicLightCalcWeight(decodedPolymorphicLight, surfaceInteraction, isSubSurface);
 
       // Accumulate the light's weight
 
@@ -227,7 +232,8 @@ bool sampleLightAdvancedRIS(
       const SurfaceMaterialInteractionSplitWeight splitWeight = opaqueSurfaceMaterialInteractionCalcApproxProjectedWeight(opaqueSurfaceMaterialInteraction, minimalRayInteraction, inputDirection);
       // Note: Only divide by the light sample's PDF if it is non-zero (as it may be zero when sampling a light from a specific location is impossible).
       const float lightThroughput = candidateSample.solidAnglePdf > 0.0f ? 1.0f / candidateSample.solidAnglePdf : 0.0f;
-      const float targetPdf = calcBt709Luminance(candidateSample.radiance * (splitWeight.diffuseReflectionWeight + splitWeight.specularReflectionWeight));
+      const float targetPdf = calcBt709Luminance(candidateSample.radiance * (
+        splitWeight.diffuseReflectionWeight + splitWeight.specularReflectionWeight + splitWeight.diffuseTransmissionWeight));
 
       // Accumulate the light's weight
       const float risWeight = targetPdf * rangeInvSourcePdf * lightThroughput;
@@ -304,7 +310,7 @@ bool sampleLightRIS(
   switch(kSurfaceRISType)
   {
   case 0:
-    return sampleLightBasicRIS(randomState, surfaceInteraction, lightSample, inverseSelectionPdf);
+    return sampleLightBasicRIS(randomState, surfaceInteraction, opaqueSurfaceMaterialInteraction, lightSample, inverseSelectionPdf);
   case 1:    
     return sampleLightAdvancedRIS(randomState, surfaceInteraction, opaqueSurfaceMaterialInteraction, viewDirection, lightSample, inverseSelectionPdf, lightIndex);
   case 2:

src/dxvk/shaders/rtx/algorithm/nee_cache.h

@@ -505,6 +505,7 @@ struct NEECell
     float ndotm = saturate(dot(halfVector, normal));
     float specularTerm = specularRatio * evalGGXNormalDistributionIsotropic(roughness, ndotm) * cb.neeCacheArgs.specularFactor * 0.25;
 
+    // TODO: SSS - Add transmission radiance
     float radiance = candidate.getRadiance();
     return radiance * (diffuseTerm + specularTerm) * ndoti;
   }