All-in-one repository including all relevant pieces to see NRD (NVIDIA Real-time Denoisers) in action. The sample is cross-platform, it's based on NRI (NVIDIA Rendering Interface) to bring cross-GraphicsAPI support.

NRD sample is a land for high performance path tracing for games. Some features to highlight:

• minimalistic path tracer utilizing Trace Ray Inline
• HALF resolution (checkerboard), FULL resolution and FULL resolution tracing with PROBABILISTIC diffuse / specular selection at the primary hit
• NRD denoising, including occlusion-only and spherical harmonics (spherical gaussians) modes
• overhead-free multi-bounce propagation (even in case of a single bounce) based on reusing the previously denoised frame
• SHARC radiance cache
• reference accumulation
• several rays per pixel and bounces
• realistic glass with multi-bounce reflections and refractions
• mip level calculation
• curvature estimation
• native integration of DLSS-SR and DLSS-RR via NGX API (not StreamLine)

GitHub branches:

• main - "all-in-one" branch: all possible options and settings are there. Since this branch covers all aspects, it's for NRD development and maintenance mostly
• simplex - "best practices" branch: optimized for the recommended usage (the path tracer does a probabilistic split at the primary hit, HitDistanceReconstructionMode::AREA_3X3 enabled in NRD). This branch is recommended to borrow best practices of path tracing and NRD usage. It offers better performance and has less code

• Install Cmake 3.30+
• Build (variant 1) - using Git and CMake explicitly
  • Clone project and init submodules
  • Generate and build project using CMake
  • To build the binary with static MSVC runtime, add -DCMAKE_MSVC_RUNTIME_LIBRARY="MultiThreaded$<$<CONFIG:Debug>:Debug>" parameter when deploying the project
• Build (variant 2) - by running scripts:
  • Run 1-Deploy
  • Run 2-Build

• USE_MINIMAL_DATA=OFF - download minimal resource package (90MB)

• Run 3-Run NRD sample script and answer the cmdline questions to set the runtime parameters
• If Smart Command Line Arguments extension for Visual Studio is installed, all command line arguments will be loaded into corresponding window
• The executables can be found in _Bin. The executable loads resources from _Data, therefore please run the samples with working directory set to the project root folder (needed pieces of the command line can be found in 3-Run NRD sample script)

Any ray tracing compatible GPU.

• Right mouse button + W/S/A/D - move camera
• Mouse scroll - accelerate / decelerate
• F1 - toggle "gDebug" (can be useful for debugging and experiments)
• F2 - go to next test (only if TESTS section is unfolded)
• F3 - toggle emission
• Tab - UI toggle
• Space - animation toggle
• PgUp/PgDown - switch between denoisers

By default NRD is used in common mode. But it can also be used in occlusion-only (including directional) and SH (spherical harmonics) modes in the sample. To change the behavior NRD_MODE macro needs to be changed from NORMAL to OCCLUSION, SH or DIRECTIONAL_OCCLUSION in Shared.hlsli.

Notes:

• RELAX doesn't support AO / SO denoising. If RELAX is the current denoiser, ambient term will be flat, but energy correct.