pissang / mutracer

MuTracer 
**MuTracer** is a physically based path tracer for the web.
It renders on WebGPU and falls back to WebGL 2, with OpenPBR materials,
TinyBVH acceleration and denoising built in.
Try the
viewer. MuTracer is a 0.x library;
APIs may change between minor releases.
- **WebGPU first, WebGL 2 as fallback**: unidirectional progressive path
 tracing with next-event estimation and multiple importance sampling over
 rect, sphere, spot (with IES profiles), directional and HDR environment
 lights. Without WebGPU, the same code renders on WebGL 2.
- **OpenPBR 1.1 surface**: F82 metals, anisotropic GGX specular and coat,
 fuzz, thin-film interference, dispersive transmission with absorption and
 volume scattering, subsurface scattering, emission and ray-marched
 height-field displacement.
- **Interactive with millions of triangles**: a two-level BVH whose BLASes are
 built with binned SAH in parallel Workers (a JavaScript port of TinyBVH, or
 the TinyBVH WebAssembly builder with SBVH and CWBVH layouts). Moving
 instances only refits the TLAS. See performance.
- **Low-noise sampling and denoising**: Owen-scrambled Sobol or blue-noise
 ZSobol sequences. Albedo- and normal-guided denoising with Intel Open Image
 Denoise (WebGPU) or a joint non-local means filter (WebGPU and WebGL 2),
 while the image converges or on the final frame.
- **Incremental Three.js sync**: `THREESync` converts standard and physical
 materials, lights, instancing, skinning and morph targets, and picks up
 transform, material and light edits on every update without reconverting
 the scene.
- **Offline-quality output**: deterministic `converge()` with variance-driven
 adaptive sampling (WebGPU); AgX, ACES, Cineon, Reinhard and linear tone
 mapping, color grading, bloom, thin-lens depth of field, shadow catchers and
 transparent backgrounds.
## Gallery
Rendered live in the browser. Click an image to open the scene in the viewer.
 Yamaha MT-09 · metal and coat · VTX , CC-BY-NC-SA 4.0 
 Super Human · subsurface skin · Davyd Vidiger , CC-BY 4.0 
 Gelatinous Cube · transmission · glenatron , CC-BY-NC 4.0 
 Dragon · glass · Delatronic , CC-BY 3.0 
 Blender Cover Remix · characters · bandinopla , CC-BY 4.0 
 Material spheres · OpenPBR layers · procedural, CC0 
## Performance
The LEGO Technic Bugatti Chiron
( VTX , CC-BY-NC-SA 4.0)
is a heavy scene that path traces interactively in the viewer:
| | Bugatti Chiron |
| --- | --- |
| Rendered triangles | 4.6 M (2.5 M unique, 341 geometries in 560 meshes) |
| Materials | 35 |
| Download | 12.8 MB `.glb` |
| BVH build, 1 thread | 1.7 s (built-in builder) / 1.0 s (TinyBVH WebAssembly) |
| BVH build, 4 workers (default) | 0.50 s (built-in builder) / 0.28 s (TinyBVH WebAssembly) |
| 1920 × 1080, 64 spp | 12.1 s path tracing, 12.4 s with OIDN denoising |
Measured on an Apple M4 Max: rendering in Chrome with WebGPU at the viewer's
default settings (6 bounces), BVH builds on CPU threads excluding worker startup.
## Install
 [code] 
Install `three` to l