🐲 minidraco

A fast, pure-TypeScript Draco mesh decoder with a drop-in DRACOLoader for Three.js — no wasm to host or fetch, and an optional worker pool so decoding never blocks the main thread.

Usage

import { GLTFLoader } from 'three/examples/jsm/loaders/GLTFLoader.js'
import { MinidracoLoader } from 'minidraco/three'

const gltfLoader = new GLTFLoader()
gltfLoader.setDRACOLoader(new MinidracoLoader())
gltfLoader.load('model.glb', gltf => scene.add(gltf.scene))

A drop-in for THREE.DRACOLoader. Decoding runs on the main thread by default. Opt into a worker pool if you prefer to keep it free:

new MinidracoLoader({ workers: true }) // decode in a pool of 4 workers
new MinidracoLoader({ workerLimit: 8 }) // pool of 8

Or decode a raw bitstream without Three.js:

import { decodeDracoMesh } from 'minidraco'

const mesh = decodeDracoMesh(new Uint8Array(bytes))

Features

• Every Draco triangle mesh — all encodings, prediction schemes, and attribute types.
• Bit-identical to the official wasm decoder, verified in the tests.
• No point clouds (glTF Draco is always meshes).

Performance

Median across 18 models vs draco.js and the official draco3d wasm decoder (full results in BENCH.md):

| benchmark | vs draco.js | vs draco3d wasm | | -------------------------------------------------- | --------------- | --------------- | | single-threaded decode — bun (JSC) | 🟢 1.82× faster | 🟢 1.97× faster | | single-threaded decode — Chrome (V8) | 🟢 1.79× faster | 🟢 1.48× faster | | GLTFLoader.parse, warm worker pool — Chrome (V8) | 🟢 1.74× faster | 🟢 1.03× faster | | GLTFLoader.parse, cold first load — Chrome (V8) | 🟢 1.60× faster | 🟢 1.38× faster |

Download size

| download (brotli) | minidraco | vs draco.js | vs draco3d wasm | | ----------------------------- | --------- | ------------------------ | ------------------------ | | single-threaded (default) | 21 KB | 🟢 1.04× smaller (22 KB) | 🟢 3.80× smaller (81 KB) | | worker pool (workers: true) | 44 KB | 🟢 not supported | 🟢 1.84× smaller (81 KB) |

Monorepo

• library/ — the minidraco package
• example/ — Next.js + React Three Fiber demo with an in-browser benchmark at /bench

bun install
bun dev        # watch build + demo
bun run all    # format, lint, typecheck, tests
bun run bench  # cross-decoder benchmark

License

MIT — initially derived from mrdoob/draco.js (MIT), implementing Google's Draco bitstream (Apache-2.0).