Luxelith – Unity3d Hyper‑Performant URP Voxel Engine

Luxelith is a Unity project showcasing a hyper‑performant voxel world renderer powered by Compute Shaders and greedy meshing on the GPU. It streams chunks around the player, generates terrain with Burst/Jobs, and builds meshes via a shared GPU mesher with async readback. The goal of this project was to create a Unity voxel engine that does not use GameObject based chunks and CPU bound mesh generation like most tutorials on the internet, but rather calculating as much as possible using compute shaders, as well as using multithreading to make the best possible voxel engine I could in Unity for my own projects. I wanted to share this code so anybody would be able to use this as a basis for their own Voxel Projects in Unity.

Key modules

• GPU meshing (compute + greedy) with per‑face textures
• Streaming and terrain generation (Burst/Jobs)
• Block database (per‑face Texture2DArray indices) and editor tooling
• Fly camera and diagnostics overlays

For detailed documentation, see the docs folder:

• docs/overview.md
• Per‑script reference stubs in docs/scripts/

Quick start

• Unity version: see ProjectSettings/ProjectVersion.txt (tested with 6000.0.24f1)
• Open the project at HyperPerformantGPURendering/
• In a scene, add:
  • WorldStreamer (assign ComputeShader/Material or let it auto‑load from Resources)
  • BlockDatabaseIntegration (assign a BlockDefinitionDatabase asset)
  • PlayerFlyController on the Camera rig and assign it to the Player field in the World Streamer
• Create/assign Assets/BlockDefinitionDatabase.asset with a Texture2DArray atlas; open Tools > Voxel Engine > Block Editor to author per‑face indices.
• Play. The world streams around the player in a deterministic spiral.

You can also use the already pre-setup default scene.

Features

• ComputeShader greedy mesher with per‑face texture indices
• Async GPU readback + MeshData API to reduce GC and main‑thread stalls
• Deterministic streaming order, distance‑based unload
• Burst IJob terrain generation (FBM sample included)
• Editor Block Editor with live per‑face preview from Texture2DArray
• Build diagnostics overlay (FPS, frame time, memory, compute support)

Showcase

Project layout

• Assets/ActualStuff/Scripts/Voxels
  • ChunkDefs, Chunk, WorldStreamer, GpuMesher, TerrainGeneration (GenerateChunkVoxelsJob), BuildDiagnostic
  • BlockDefinition, BlockDefinitionDatabase, BlockDatabaseIntegration, BlockTypes (ids & UV triplets)
• Assets/ActualStuff/EditorStuff
  • Editor: BlockEditor, TextureArrayShaderGUI
  • Scripts/Voxels: BlockTypes (BlockId, UV triplets, static BlockDatabase used by GPU mesher)

See docs/scripts/ for per‑file notes.

How it works (high‑level)

• WorldStreamer

  • Computes a streaming center (player/camera), keeps chunks within viewDistanceChunks
  • Schedules GenerateChunkVoxelsJob to fill NativeArray<byte> voxels
  • Queues ready chunks, feeds them to a shared GpuMesher
  • Reads back counters then vertex/index streams; applies via MeshData; draws with Graphics.DrawMesh

• GpuMesher

  • Manages ComputeBuffers (voxels, counters, vertices, indices, UV triplets, per‑face textures)
  • Dispatches greedy kernels for ±X/±Y/±Z planes
  • Supports per‑face texture mapping via [blockCount*6] buffer uploaded by BlockDatabaseIntegration

• Blocks & textures

  • BlockDefinitionDatabase stores BlockDefinitions (id, per‑face texture indices, gameplay flags)
  • BlockDatabaseIntegration uploads per‑face indices to the mesher
  • BlockEditor (EditorWindow) previews/edits faces and reads slices from Texture2DArray

Build and run notes

• Ensure target platform supports compute shaders and URP (or the target shader)
• Provide a Texture2DArray with one tile per material slice; set array slice count on the material/shader if required
• Add a Directional Light for sun direction (optional). Defaults to Vector3.down if missing

Troubleshooting

• No meshes: assign/locate Resources/VoxelMesher.compute or set voxelMesher in WorldStreamer
• All faces same texture: ensure BlockDatabaseIntegration is in scene and database has a valid Texture2DArray; use its Refresh action
• Editor preview shows color tiles: extraction fallback when array isn’t readable; verify Texture2DArray asset
• Performance: enable BuildDiagnostic, reduce viewDistanceChunks/maxGeneratePerFrame

License

See LICENSE.