Nanite-style virtualized geometry renderer on DirectX 12

Nanite-style virtualized geometry renderer on DirectX 12 (built on Microsoft MiniEngine).

Nyx is a personal research project focused on extreme-scale geometry rendering: continuous LOD, GPU-driven culling, mesh-shader dispatch, and demand-driven geometry streaming.

The current stress test scene is Zorah (NVIDIA), with:

• 1,639,668,228 unique triangles
• 18,949,504,889 instanced triangles

Showcase

Test platform for the screenshots/video below: i7-14700KF + RTX 4070 Ti SUPER, rendered at 4K.

Demo video:

<h2 align="center">🎬 Nyx – Nanite-Style Virtualized Geometry Renderer</h2> <p align="center"> <a href="https://www.youtube.com/watch?v=mBEIvRWloCw"> <img src="https://img.youtube.com/vi/mBEIvRWloCw/maxresdefault.jpg" width="1000"> </a> </p> <p align="center"> 4K • 144Hz • 18.9B Instanced Triangles • RTX 4070 Ti SUPER </p>

Screenshots:

<p align="center">Lit mode</p>

<p align="center">Meshlet mode</p>

<p align="center">Triangle mode</p>

Core Features

• Nanite-style meshlet hierarchy with DAG/BVH traversal
• GPU-driven rendering via indirect DispatchMesh
• Two-pass frustum + HZB occlusion culling
• Visibility buffer pipeline, then resolve to deferred GBuffer
• Dynamic geometry streaming with residency/address table updates
• Async page IO + LZ4-compressed geometry pages
• Runtime debug/tuning UI (pixel error, culling freeze, debug modes)

Quick Start

Requirements

• Windows 10/11
• Visual Studio 2022
• DX12 GPU with Mesh Shader support
• NuGet package restore enabled

Recommended for large scenes:

• High-VRAM GPU
• 32 GB+ RAM (48 GB+ recommended for rebuilding very large assets)
• NVMe SSD
• Large free disk space

Build

1. Open MiniEngine/SceneViewer/SceneViewer.sln
2. Select Release | x64
3. Build and run SceneViewer

By default, SceneViewer loads:

• Assets/bunny/bunny.gltf

Zorah Quick Start (Prebuilt Cache)

Building Zorah cache locally can be time-consuming and memory-intensive. If you only want to run the demo, use the prebuilt files:

• Download prebuilt Zorah package

After download, extract/copy the files to:

MiniEngine/SceneViewer/Assets/zorah_main_public/

Then run:

.\SceneViewer.exe -model .\Assets\zorah_main_public\zorah_main_public.gltf

Command Line

From the SceneViewer output directory, examples:

Typical path (default MiniEngine layout):

MiniEngine\Build\x64\Release\Output\SceneViewer\

.\SceneViewer.exe -model .\Assets\bunny\bunny.gltf
.\SceneViewer.exe -model .\Assets\Jinx\scene.gltf -instances 3600
.\SceneViewer.exe -model .\Assets\bunny\bunny.gltf -rebuild 1

Arguments:

• -model <path>: glTF/glb scene path
• -instances <N>: instance count (clamped to 1..1000000)
• -rebuild 1: force rebuild .mini cache

Controls

• W A S D / Q E: move
• Mouse: look
• Mouse wheel: movement speed scale
• Shift: fine movement toggle
• Backspace: engine tuning/debug UI

Architecture Overview

Offline / First-load Build (.gltf/.glb -> .mini)

1. Parse scene/material/camera/animation data
2. Build meshlets and meshlet groups
3. Iteratively simplify groups for multi-level LOD
4. Build hierarchy nodes and metadata
5. Pack geometry pages
6. Compress pages with LZ4
7. Save metadata + blob to .mini

Runtime Frame Flow

1. Instance culling
2. DAG/hierarchy culling (frustum + HZB)
3. Build indirect mesh dispatch args
4. Mesh shader pass 0
5. Export depth and generate HZB
6. Repeat cull + mesh shader pass 1
7. Resolve visibility buffer to GBuffer
8. Deferred lighting + post effects

Streaming Runtime

• Page size: 256 KB
• Chunk size: 256 MB
• GPU request mask readback + async page load + LZ4 decompress + upload

Technical Snapshot

• Language: C++20
• Graphics API: DirectX 12
• Shader Model: 6.6
• Agility SDK package: Microsoft.Direct3D.D3D12 1.616.1
• Meshlet defaults: max vertices 128, max triangles 128, group size 32, BVH node children 8

Repository Layout

• MiniEngine/Core: engine core and rendering systems
• MiniEngine/Model: model conversion, meshlets, culling, streaming, shaders
• MiniEngine/SceneViewer: runtime app
• MiniEngine/SceneViewer/Assets: sample and stress scenes

Notes

• To load custom glTF assets, place them under MiniEngine/SceneViewer/Assets and pass the path with -model.
• This project uses MiniEngine conventions (right-handed coordinate handling inside the renderer path).
• Large-scene build time depends heavily on CPU, storage bandwidth, and available memory.

Acknowledgements

• Unreal Engine Nanite talks and publications
• Microsoft MiniEngine
• meshoptimizer
• lz4
• cgltf
• imgui
• Inspiration references: nanite-webgpu, vk_lod_clusters

License

• Nyx source code: MIT License (LICENSE)
• Third-party components: original licenses (THIRD_PARTY_NOTICES.md)
• Scene assets may have separate licenses and restrictions; verify before redistribution

Contact

• love.jingjing.forever.1314@gmail.com