NRI is a modular, extensible, low-level abstract rendering interface that was designed to support all low-level features of D3D12 and Vulkan GAPIs. At the same time, it aims to simplify usage and reduce the amount of code needed (especially compared with VK).

Goals:

• Generalization and unification of D3D12 (spec) and VK (spec)
• Explicitness (providing access to low-level features of modern GAPIs)
• Quality-of-life and high-level extensions (e.g., streaming and upscaling)
• Low overhead
• Cross-platform and platform independence (AMD/INTEL friendly)
• D3D11 support (spec) (as much as possible)

Non-goals:

• Exposing entities not existing in GAPIs
• High-level (D3D11-like) abstraction
• Hidden management of any kind (except for some high-level extensions where it's desired)
• Automatic barriers (better handled in a higher-level abstraction)

Supported GAPIs:

• Vulkan
• D3D12
• D3D11
• Metal (through MoltenVK)
• None / dummy (everything is supported but does nothing)

There is NVRHI, which offers a D3D11-like abstraction layer, implying some overhead. There is vkd3d-proton, which was designed for D3D12 emulation using Vulkan. There is nvpro-samples, which explores all "dark corners" of Vulkan usage, but does not offer any cross-API support. There are some other good, unmentioned projects, but NRI was designed to offer a reasonably simple, low-overhead, and high-performance render interface suitable for game development, professional rendering and hobby projects. Additionally, NRI can serve as a middleware for integrations. For instance, the NRD integration layer is based on NRI, unifying multiple GAPI support within a single codebase.

• C++ and C compatible interfaces
• generalized common denominator for D3D12, VK and D3D11
• low overhead
• no memory allocations at runtime
• descriptor indexing support
• ray tracing support
• mesh shaders support
• D3D12 Ultimate features support, including enhanced barriers
• VK printf support
• validation layers (GAPI- and NRI- provided)
• user provided memory allocator support
• default D3D11 behavior is changed to match D3D12/VK using NVAPI or AMD AGS libraries, where applicable
• supporting as much as possible VK-enabled platforms: Windows, Linux, MacOS, Android
• debug names and annotations for CPU and GPU timelines (GAPI, NVTX and PIX, if "WinPixEventRuntime.dll" is nearby)
• can be used as a shared or static library

Available interfaces:

• NRI.h - core functionality
• NRIDeviceCreation.h - device creation and related functionality
• NRIHelper.h - a collection of various helpers to ease use of the core interface
• NRIImgui.h - a light-weight ImGui renderer (no ImGui dependency)
• NRILowLatency.h - low latency support (aka NVIDIA REFLEX)
• NRIMeshShader.h - mesh shaders
• NRIRayTracing.h - ray tracing
• NRIResourceAllocator.h - convenient creation of resources using AMD Virtual Memory Allocator, which get returned already bound to memory
• NRIStreamer.h - a convenient way to stream data into resources
• NRISwapChain.h - swap chain and related functionality
• NRIUpscaler.h - a configurable collection of common upscalers (NIS, FSR, DLSS-SR, DLSS-RR)

Repository organization:

• there is only main branch used for development
• stable versions are in Releases section

• Install Cmake 3.30+
• Build (variant 1) - using Git and CMake explicitly
  • Clone project and init submodules
  • Generate and build the 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

Notes:

• Xlib and Wayland can be both enabled
• Minimal supported client is Windows 8.1+. Windows 7 support requires minimal effort and can be added by request

• NRI_AGILITY_SDK_DIR - Directory where Agility SDK will be copied relative to the directory with binaries
• NRI_AGILITY_SDK_VERSION_MAJOR- Agility SDK major version
• NRI_AGILITY_SDK_VERSION_MINOR - Agility SDK minor version
• NRI_SHADERS_PATH - Shader output path override
• NRI_STATIC_LIBRARY - Build static library
• NRI_ENABLE_NVTX_SUPPORT - Annotations for NVIDIA Nsight Systems
• NRI_ENABLE_DEBUG_NAMES_AND_ANNOTATIONS - Enable debug names, host and device annotations
• NRI_ENABLE_NONE_SUPPORT - Enable NONE backend
• NRI_ENABLE_VK_SUPPORT - Enable Vulkan backend
• NRI_ENABLE_VALIDATION_SUPPORT - Enable Validation backend (otherwise enableNRIValidation is ignored)
• NRI_ENABLE_NIS_SDK - Enable NVIDIA Image Sharpening SDK
• NRI_ENABLE_IMGUI_EXTENSION - Enable NRIImgui extension
• NRI_ENABLE_D3D11_SUPPORT - Enable D3D11 backend
• NRI_ENABLE_D3D12_SUPPORT - Enable D3D12 backend
• NRI_ENABLE_D3D_EXTENSIONS - Enable vendor specific extension libraries for D3D (NVAPI and AMD AGS)
• NRI_ENABLE_AGILITY_SDK_SUPPORT - Enable Agility SDK support to unlock access to latest D3D12 features
• NRI_ENABLE_XLIB_SUPPORT - Enable X11 support
• NRI_ENABLE_WAYLAND_SUPPORT - Enable Wayland support
• NRI_ENABLE_NGX_SDK - Enable NVIDIA NGX (DLSS) SDK
• NRI_ENABLE_FFX_SDK - Enable AMD FidelityFX SDK
• NRI_ENABLE_XESS_SDK - Enable INTEL XeSS SDK

Overview and Download sections can be found here.

D3D12 backend uses Agility SDK to get access to most recent D3D12 features. It's highly recommended to use it.

Steps (already enabled by default):

• modify NRI_AGILITY_SDK_VERSION_MAJOR and NRI_AGILITY_SDK_VERSION_MINOR to the desired value
• enable or disable NRI_ENABLE_AGILITY_SDK_SUPPORT
• re-deploy project
• include auto-generated NRIAgilitySDK.h header in the code of your executable using NRI

NRD sample:

• main sample demonstrating path tracing best practices

NRI samples:

• DeviceInfo - queries and prints out information about device groups in the system
• Clear - minimal example of rendering using framebuffer clears only
• CTest - very simple example of C interface usage
• Triangle - simple textured triangle rendering (also multiview demonstration in FLEXIBLE mode)
• SceneViewer - loading & rendering of meshes with materials (also tests programmable sample locations, shading rate and pipeline statistics)
• BindlessSceneViewer - bindless GPU-driven rendering test
• Readback - getting data from the GPU back to the CPU
• AsyncCompute - demonstrates parallel execution of graphic and compute workloads
• MultiThreading - shows advantages of multi-threaded command buffer recording
• Multiview - multiview demonstration in LAYER_BASED mode (VK and D3D12 compatible)
• MultiGPU - multi GPU example
• RayTracingTriangle - simple triangle rendering through ray tracing
• RayTracingBoxes - a more advanced ray tracing example with many BLASes in TLAS
• Wrapper - shows how to wrap native D3D11/D3D12/VK objects into NRI entities
• Resize - demonstrates window resize

NRI is licensed under the MIT License.