NRD v3.6.0:

HIGHLIGHTS: - NRD: removed "SpecularLobeTrimmingParameters" - NRD: improved NRD SDK generation script - REBLUR: regression and bug fixes (sorry, it's an expected side effect of doing steps forward) - REBLUR: improved IQ and performance DETAILS: - NRD: removed "SpecularLobeTrimmingParameters" - NRD: improved NRD SDK generation script - NRD: Fooplot graphs replaced with Desmos graphs - NRD: improved compatibility with HLSL 2021 (WIP) - NRD: clarified in comments where NRD_USE_OCT_NORMAL_ENCODING and NRD_USE_MATERIAL_ID come from - NRD: getting rid of point-mirror samplers in the shader code - REBLUR: changed estimation of optimal hitT for tracking - REBLUR: added random rotation to HistoryFix pass - REBLUR: hitT for very low roughness is not modified by HistoryFix pass (already clean) - REBLUR: made another attempt to properly tune virtual parallax based history rejection - REBLUR: fixed SH related bug in pre-pass (regression) - REBLUR: improved SH denoising (pre-pass now behaves as "advanced" since direction and PDF are available) - REBLUR: unified hitT weight between radiance and hitT - REBLUR: unified hit distance factor - REBLUR: improved performance - REBLUR: fixed a rare case of out-of-bounds access, when unused half of a resource is filled with NaNs - REBLUR: improved calculation of virtual motion based accumulation speed for specular - REBLUR: blur radius refactoring (all relevant code gathered in one place for clarity) - REBLUR: fixed a minor issue in debug visualization - REBLUR: tuned blur radius "addon" - REBLUR: code refactoring and simplification - SIGMA: changed shader names to match overall REBLUR style (no functional changes) - updated README & UPDATE
NVIDIA-RTX · Sep 5, 2022 · 247382b · 247382b
1 parent 39b7ae9
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diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
@@ -41,7 +41,7 @@ jobs:
       - 
         name: Prepare NRD SDK
         run: |
-          &'.\3-Prepare NRD SDK.bat' --no-pause --copy-shaders
+          &'.\3-Prepare NRD SDK.bat' --no-pause --shaders
       - 
         name: Upload NRD SDK as artefact
         uses: actions/upload-artifact@v3

diff --git a/3-Prepare NRD SDK.bat b/3-Prepare NRD SDK.bat
@@ -4,17 +4,22 @@ set NRD_DIR=.
 set "use_pause=y"
 set "copy_shaders="
 set "no_copy_shaders="
+set "copy_integration="
+set "no_copy_integration="
 
 :PARSE
 if "%~1"=="" goto :MAIN
 
-if /i "%~1"=="-h"                goto :HELP
-if /i "%~1"=="--help"            goto :HELP
+if /i "%~1"=="-h" goto :HELP
+if /i "%~1"=="--help" goto :HELP
 
-if /i "%~1"=="--no-pause"        set "use_pause="
+if /i "%~1"=="--no-pause" set "use_pause="
 
-if /i "%~1"=="--copy-shaders"    set "copy_shaders=y"
-if /i "%~1"=="--no-copy-shaders" set "no_copy_shaders=y"
+if /i "%~1"=="--shaders"    set "copy_shaders=y"
+if /i "%~1"=="--no-shaders" set "no_copy_shaders=y"
+
+if /i "%~1"=="--integration" set "copy_integration=y"
+if /i "%~1"=="--no-integration" set "no_copy_integration=y"
 
 shift
 goto :PARSE
@@ -24,43 +29,64 @@ goto :PARSE
 rd /q /s "_NRD_SDK"
 
 mkdir "_NRD_SDK\Include"
-mkdir "_NRD_SDK\Integration"
 mkdir "_NRD_SDK\Lib\Debug"
 mkdir "_NRD_SDK\Lib\Release"
+mkdir "_NRD_SDK\Shaders"
+mkdir "_NRD_SDK\Shaders\Include"
 
 cd "_NRD_SDK"
 
-copy "..\%NRD_DIR%\Integration\*" "Integration"
 copy "..\%NRD_DIR%\Include\*" "Include"
 copy "..\_Build\Debug\NRD.dll" "Lib\Debug"
 copy "..\_Build\Debug\NRD.lib" "Lib\Debug"
 copy "..\_Build\Debug\NRD.pdb" "Lib\Debug"
 copy "..\_Build\Release\NRD.dll" "Lib\Release"
 copy "..\_Build\Release\NRD.lib" "Lib\Release"
+copy "..\%NRD_DIR%\Shaders\Include\NRD.hlsli" "Shaders\Include"
 copy "..\%NRD_DIR%\LICENSE.txt" "."
 copy "..\%NRD_DIR%\README.md" "."
 
 echo.
 if defined copy_shaders goto :SHADERS
-if defined no_copy_shaders goto :END
+if defined no_copy_shaders goto :PRE_INTEGRATION
 set /P M=Do you need the shader source code for a white-box integration? [y/n]
-if /I "%M%" neq "y" goto END
+if /I "%M%" neq "y" goto :PRE_INTEGRATION
 
 :SHADERS
+
 mkdir "Shaders"
 
-xcopy "..\%NRD_DIR%\Shaders\" "Shaders" /s
+xcopy "..\%NRD_DIR%\Shaders\" "Shaders" /s /y
 copy "..\%NRD_DIR%\External\MathLib\*.hlsli" "Shaders\Source"
 
+:PRE_INTEGRATION
+
+echo.
+if defined copy_integration goto :INTEGRATION
+if defined no_copy_integration goto :END
+set /P M=Do you need NRD integration layer? [y/n]
+if /I "%M%" neq "y" goto :END
+
+:INTEGRATION
+
+mkdir "Integration"
+copy "..\%NRD_DIR%\Integration\*" "Integration"
+
+cd ..
+
 :END
 
 cd ..
 if defined use_pause pause
-exit
+exit /b %errorlevel%
 
 :HELP
+
 echo. -h, --help          show help message
-echo. --no-pause          skip pause in the end of script
-echo. --copy-shaders      copy shadres for a white-box integration
-echo. --no-copy-shaders   don't copy shadres for a white-box integration
+echo. --no-pause          skip pause at the end of the script
+echo. --shaders           copy shaders for a white-box integration
+echo. --no-shaders        do not copy shaders for a white-box integration
+echo. --integration       copy NRD integration layer
+echo. --no-integration    do not copy NRD integration layer
+
 exit
diff --git a/3-Prepare NRD SDK.sh b/3-Prepare NRD SDK.sh
@@ -5,16 +5,17 @@ NRD_DIR=.
 rm -rf "_NRD_SDK"
 
 mkdir -p "_NRD_SDK/Include"
-mkdir -p "_NRD_SDK/Integration"
 mkdir -p "_NRD_SDK/Lib/Debug"
 mkdir -p "_NRD_SDK/Lib/Release"
+mkdir -p "_NRD_SDK/Shaders"
+mkdir -p "_NRD_SDK/Shaders/Include"
 
 cd "_NRD_SDK"
 
-cp -r ../$NRD_DIR/Integration/ "Integration"
 cp -r ../$NRD_DIR/Include/ "Include"
 cp -H ../_Build/Debug/libNRD.so "Lib/Debug"
 cp -H ../_Build/Release/libNRD.so "Lib/Release"
+cp ../$NRD_DIR/Shaders/Include/NRD.hlsli "Shaders/Include"
 cp ../$NRD_DIR/LICENSE.txt "."
 cp ../$NRD_DIR/README.md "."
 
@@ -28,4 +29,13 @@ then
     cp ../$NRD_DIR/External/MathLib/*.hlsli "Shaders\Source"
 fi
 
+read -p "Do you need NRD integration layer? [y/n]" -n 1 -r
+echo
+if [[ $REPLY =~ ^[Yy]$ ]]
+then
+    mkdir -p "Integration"
+
+    cp -r ../$NRD_DIR/Integration/ "Integration"
+fi
+
 cd ..
diff --git a/External/MathLib b/External/MathLib
diff --git a/Include/NRD.h b/Include/NRD.h
@@ -28,9 +28,9 @@ license agreement from NVIDIA CORPORATION is strictly prohibited.
 #include <cstddef>
 
 #define NRD_VERSION_MAJOR 3
-#define NRD_VERSION_MINOR 5
+#define NRD_VERSION_MINOR 6
 #define NRD_VERSION_BUILD 0
-#define NRD_VERSION_DATE "1 September 2022"
+#define NRD_VERSION_DATE "6 September 2022"
 
 #if defined(_MSC_VER)
     #define NRD_CALL __fastcall

diff --git a/Include/NRDDescs.h b/Include/NRDDescs.h
@@ -11,7 +11,7 @@ license agreement from NVIDIA CORPORATION is strictly prohibited.
 #pragma once
 
 #define NRD_DESCS_VERSION_MAJOR 3
-#define NRD_DESCS_VERSION_MINOR 5
+#define NRD_DESCS_VERSION_MINOR 6
 
 static_assert (NRD_VERSION_MAJOR == NRD_DESCS_VERSION_MAJOR && NRD_VERSION_MINOR == NRD_DESCS_VERSION_MINOR, "Please, update all NRD SDK files");
 
@@ -353,8 +353,8 @@ namespace nrd
         uint8_t versionMajor;
         uint8_t versionMinor;
         uint8_t versionBuild;
-        uint8_t maxSupportedMaterialBitNum;
-        bool isCompiledWithOctPackNormalEncoding : 1;
+        uint8_t maxSupportedMaterialBitNum; // if 0, compiled with NRD_USE_MATERIAL_ID = 0
+        bool isCompiledWithOctPackNormalEncoding : 1; // if 0, compield with NRD_USE_OCT_NORMAL_ENCODING = 0
     };
 
     struct MethodDesc

diff --git a/Include/NRDSettings.h b/Include/NRDSettings.h
@@ -11,7 +11,7 @@ license agreement from NVIDIA CORPORATION is strictly prohibited.
 #pragma once
 
 #define NRD_SETTINGS_VERSION_MAJOR 3
-#define NRD_SETTINGS_VERSION_MINOR 5
+#define NRD_SETTINGS_VERSION_MINOR 6
 
 static_assert (NRD_VERSION_MAJOR == NRD_SETTINGS_VERSION_MAJOR && NRD_VERSION_MINOR == NRD_SETTINGS_VERSION_MINOR, "Please, update all NRD SDK files");
 
@@ -157,20 +157,6 @@ namespace nrd
         float D = -25.0f;
     };
 
-    // Optional specular lobe trimming = A * smoothstep( B, C, roughness )
-    // Recommended settings if lobe trimming is needed = { 0.85f, 0.04f, 0.11f }
-    struct SpecularLobeTrimmingParameters
-    {
-        // [0; 1] - main level  (0 - GGX dominant direction, 1 - full lobe)
-        float A = 1.0f;
-
-        // [0; 1] - max trimming if roughness is less than this threshold
-        float B = 0.0f;
-
-        // [0; 1] - main level if roughness is greater than this threshold
-        float C = 0.0001f;
-    };
-
     // Antilag logic:
     //    delta = ( abs( old - new ) - localVariance * sigmaScale ) / ( max( old, new ) + localVariance * sigmaScale + sensitivityToDarkness )
     //    delta = LinearStep( thresholdMax, thresholdMin, delta )
@@ -214,7 +200,6 @@ namespace nrd
 
     struct ReblurSettings
     {
-        SpecularLobeTrimmingParameters specularLobeTrimmingParameters = {};
         HitDistanceParameters hitDistanceParameters = {};
         AntilagIntensitySettings antilagIntensitySettings = {};
         AntilagHitDistanceSettings antilagHitDistanceSettings = {};

diff --git a/Integration/NRDIntegration.h b/Integration/NRDIntegration.h
@@ -21,8 +21,8 @@ license agreement from NVIDIA CORPORATION is strictly prohibited.
 
 #define NRD_INTEGRATION 1
 #define NRD_INTEGRATION_MAJOR 3
-#define NRD_INTEGRATION_MINOR 0
-#define NRD_INTEGRATION_DATE "14 July 2022"
+#define NRD_INTEGRATION_MINOR 2
+#define NRD_INTEGRATION_DATE "6 September 2022"
 
 // Settings
 #ifndef NRD_INTEGRATION_ASSERT

diff --git a/Integration/NRDIntegration.hpp b/Integration/NRDIntegration.hpp
@@ -10,7 +10,7 @@ license agreement from NVIDIA CORPORATION is strictly prohibited.
 
 #include "NRDIntegration.h"
 
-static_assert(NRD_VERSION_MAJOR >= 3 && NRD_VERSION_MINOR >= 4, "Unsupported NRD version!");
+static_assert(NRD_VERSION_MAJOR >= 3 && NRD_VERSION_MINOR >= 6, "Unsupported NRD version!");
 
 #if _WIN32
     #define NRD_INTEGRATION_ALLOCA _alloca
@@ -449,7 +449,7 @@ void NrdIntegration::Dispatch(nri::CommandBuffer& commandBuffer, nri::Descriptor
             {
                 nrdTexture = (NrdIntegrationTexture*)&userPool[(uint32_t)nrdResource.type];
 
-                NRD_INTEGRATION_ASSERT( nrdTexture && nrdTexture->subresourceStates && nrdTexture->subresourceStates->texture, "IN_XXX can't be NULL if it's in use!");
+                NRD_INTEGRATION_ASSERT( nrdTexture && nrdTexture->subresourceStates && nrdTexture->subresourceStates->texture, "'userPool' entry can't be NULL if it's in use!");
                 NRD_INTEGRATION_ASSERT( nrdTexture->format != nri::Format::UNKNOWN, "Format must be a valid format!");
             }
 

diff --git a/README.md b/README.md
@@ -1,4 +1,4 @@
-# NVIDIA Real-time Denoisers v3.5.0 (NRD)
+# NVIDIA Real-time Denoisers v3.6.0 (NRD)
 
 ## SAMPLE APP
 
@@ -169,7 +169,7 @@ commandBufferDesc.d3d12CommandAllocator = (ID3D12CommandAllocator*)d3d12CommandA
 nri::CommandBuffer* nriCommandBuffer = nullptr;
 NRI.CreateCommandBufferD3D12(*nriDevice, commandBufferDesc, nriCommandBuffer);
 
-// Wrap required textures
+// Wrap required textures (better do it only once on initialization)
 nri::TextureTransitionBarrierDesc entryDescs[N] = {};
 nri::Format entryFormat[N] = {};
 
@@ -217,14 +217,18 @@ NrdUserPool userPool = {};
     NrdIntegration_SetResource(userPool, ...);
 };
 
-NRD.Denoise(*nriCommandBuffer, commonSettings, userPool);
+// Better use "true" if NRI texture wrappers are non-volatile between frames
+bool enableDescriptorCaching = true;
+
+NRD.Denoise(frameIndex, *nriCommandBuffer, commonSettings, userPool, enableDescriptorCaching);
 
 // IMPORTANT: NRD integration binds own descriptor pool, don't forget to re-bind back your descriptor pool (heap)
 
 //====================================================================================================================
 // SHUTDOWN or RENDER - CLEANUP
 //====================================================================================================================
 
+// Better do it only once on shutdown
 for (uint32_t i = 0; i < N; i++)
     NRI.DestroyTexture(entryDescs[i].texture);
 
@@ -308,6 +312,8 @@ Commons inputs:
   - project on screen using matrices passed to NRD
   - `.w` component is positive view Z (or just transform world space position to main view space and take `.z` component)
 
+**IMPORTANT**: All textures should be *NaN* free at each pixel, even at pixels outside of denoising range.
+
 See `NRDDescs.h` for more details and descriptions of other inputs and outputs.
 
 ## NOISY DATA REQUIREMENTS

diff --git a/Resources/Version.h b/Resources/Version.h
@@ -22,7 +22,7 @@ Versioning rules:
 */
 
 #define VERSION_MAJOR                   3
-#define VERSION_MINOR                   5
+#define VERSION_MINOR                   6
 #define VERSION_BUILD                   0
 #define VERSION_REVISION                0
 

diff --git a/Shaders/Include/Common.hlsli b/Shaders/Include/Common.hlsli
@@ -107,9 +107,9 @@ float PixelRadiusToWorld( float unproject, float orthoMode, float pixelRadius, f
      return pixelRadius * unproject * lerp( viewZ, 1.0, abs( orthoMode ) );
 }
 
-float GetHitDistFactor( float hitDist, float frustumHeight, float scale = 1.0 )
+float GetHitDistFactor( float hitDist, float frustumHeight )
 {
-    return saturate( hitDist / ( hitDist * scale + frustumHeight ) );
+    return saturate( hitDist / frustumHeight );
 }
 
 float4 GetBlurKernelRotation( compiletime const uint mode, uint2 pixelPos, float4 baseRotator, uint frameIndex )
@@ -152,10 +152,10 @@ float2 ApplyCheckerboardShift( float2 uv, uint mode, uint counter, float2 screen
     return ( float2( uvi ) + 0.5 ) * invScreenSize;
 }
 
+// Comparison of two methods:
+// https://www.desmos.com/calculator/xwq1nrawho
 float GetSpecMagicCurve( float roughness, float power = 0.25 )
 {
-    // http://fooplot.com/#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--
-
     float f = 1.0 - exp2( -200.0 * roughness * roughness );
     f *= STL::Math::Pow01( roughness, power );
 
@@ -164,9 +164,6 @@ float GetSpecMagicCurve( float roughness, float power = 0.25 )
 
 float GetSpecMagicCurve2( float roughness, float percentOfVolume = 0.987 )
 {
-    // http://fooplot.com/#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
-    // http://fooplot.com/#W3sidHlwZSI6MCwiZXEiOiIoMS0yXigtMjAwKngqeCkpKih4XjAuMjUpIiwiY29sb3IiOiIjMDAwMDAwIn0seyJ0eXBlIjowLCJlcSI6ImF0YW4oMC45ODcqeCp4LygxLTAuOTg3KSkvKGF0YW4oMC45ODcvKDEtMC45ODcpKSkiLCJjb2xvciI6IiMxREQ2MDAifSx7InR5cGUiOjAsImVxIjoiYXRhbigwLjk3KngqeC8oMS0wLjk3KSkvKGF0YW4oMC45Ny8oMS0wLjk3KSkpIiwiY29sb3IiOiIjQ0MzMDAwIn0seyJ0eXBlIjoxMDAwLCJ3aW5kb3ciOlsiMCIsIjEiLCIwIiwiMS4xIl0sInNpemUiOlsxMDAwLDUwMF19XQ--
-
     float angle = STL::ImportanceSampling::GetSpecularLobeHalfAngle( roughness, percentOfVolume );
     float almostHalfPi = STL::ImportanceSampling::GetSpecularLobeHalfAngle( 1.0, percentOfVolume );
 
@@ -204,8 +201,6 @@ float GetColorCompressionExposureForSpatialPasses( float roughness )
     // - the compression function must be monotonic for full roughness range
     // - returned exposure must be used with colors in the HDR range used in tonemapping, i.e. "color * exposure"
 
-    // http://fooplot.com/#W3sidHlwZSI6MCwiZXEiOiIwLjUvKDErNTAqeCkiLCJjb2xvciI6IiNGNzBBMEEifSx7InR5cGUiOjAsImVxIjoiMC41KigxLXgpLygxKzYwKngpIiwiY29sb3IiOiIjMkJGRjAwIn0seyJ0eXBlIjowLCJlcSI6IjAuNSooMS14KS8oMSsxMDAwKngqeCkrKDEteF4wLjUpKjAuMDMiLCJjb2xvciI6IiMwMDU1RkYifSx7InR5cGUiOjAsImVxIjoiMC42KigxLXgqeCkvKDErNDAwKngqeCkiLCJjb2xvciI6IiMwMDAwMDAifSx7InR5cGUiOjEwMDAsIndpbmRvdyI6WyIwIiwiMSIsIjAiLCIxIl0sInNpemUiOlsyOTUwLDk1MF19XQ--
-
     // Moderate compression
     #if( NRD_RADIANCE_COMPRESSION_MODE == 1 )
         return 0.5 / ( 1.0 + 50.0 * roughness );
@@ -338,8 +333,10 @@ float2 GetGeometryWeightParams( float planeDistSensitivity, float frustumHeight,
 
 float2 GetHitDistanceWeightParams( float hitDist, float nonLinearAccumSpeed, float roughness = 1.0 )
 {
+    // IMPORTANT: since this weight is exponential, 3% can lead to leaks from bright objects in reflections.
+    // Eeven 1% is not enough in some cases, but using a lower value makes things even more fragile
     float smc = GetSpecMagicCurve2( roughness );
-    float norm = lerp( 0.03, 1.0, min( nonLinearAccumSpeed, smc ) );
+    float norm = lerp( 0.01, 1.0, min( nonLinearAccumSpeed, smc ) );
     float a = 1.0 / norm;
     float b = hitDist * a;
 
@@ -351,12 +348,12 @@ float2 GetHitDistanceWeightParams( float hitDist, float nonLinearAccumSpeed, flo
 // IMPORTANT:
 // - works for "negative x" only
 // - huge error for x < -2, but still applicable for "weight" calculations
-// http://fooplot.com/#W3sidHlwZSI6MCwiZXEiOiJleHAoeCkiLCJjb2xvciI6IiMwMDAwMDAifSx7InR5cGUiOjAsImVxIjoiMS8oeCp4LXgrMSkiLCJjb2xvciI6IiMwRkIwMDAifSx7InR5cGUiOjEwMDAsIndpbmRvdyI6WyItMTAiLCIwIiwiMCIsIjEiXX1d
+// https://www.desmos.com/calculator/cd3mvg1gfo
 #define ExpApprox( x ) \
     rcp( ( x ) * ( x ) - ( x ) + 1.0 )
 
 // Must be used for noisy data
-// http://fooplot.com/#W3sidHlwZSI6MCwiZXEiOiIxLWFicygoeC0wLjUpLzAuMikiLCJjb2xvciI6IiMwMDAwMDAifSx7InR5cGUiOjAsImVxIjoiZXhwKC0yKmFicygoeC0wLjUpLzAuMikpIiwiY29sb3IiOiIjRkYwMDE1In0seyJ0eXBlIjowLCJlcSI6IjEvKCgtMyphYnMoKHgtMC41KS8wLjIpKV4yLSgtMyphYnMoKHgtMC41KS8wLjIpKSsxKSIsImNvbG9yIjoiIzAwQTgyNyJ9LHsidHlwZSI6MTAwMCwid2luZG93IjpbIjAiLCIxIiwiMCIsIjEiXX1d
+// https://www.desmos.com/calculator/9yoyc3is2g
 // scale = 3-5 is needed to match energy in "_ComputeNonExponentialWeight" ( especially when used in a recurrent loop )
 #define _ComputeExponentialWeight( x, px, py ) \
     ExpApprox( -NRD_EXP_WEIGHT_DEFAULT_SCALE * abs( ( x ) * ( px ) + ( py ) ) )