verekia/minidraco

🐲 minidraco

A fast, pure-TypeScript Draco mesh decoder with a drop-in DRACOLoader for Three.js — no wasm to host or fetch, and a 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, no cast needed. Decoding runs in a worker pool by default, with a main-thread fallback. Options:

new MinidracoLoader({ workers: false }) // decode on the main thread
new MinidracoLoader({ workerLimit: 8 }) // pool size (default 4)

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 a 19-model corpus vs draco.js and the official draco3d wasm decoder (full results in BENCH.md):

On par with draco.js, faster than the wasm decoder single-threaded, and competitive in a real GLTFLoader.parse with the main thread left free.

🟢 There's no draco_decoder.wasm to fetch and compile before the first decode, so minidraco (and draco.js) often beat the wasm decoder on first load (not reflected on the benchmark).

Download size

Over the wire (brotli): ~23 KB ships in your app bundle. With the worker pool on (default) the browser also fetches a ~22 KB worker chunk on the first decode — ~45 KB total; workers: false skips that fetch. draco.js ~22 KB, draco3d wasm ~76 KB — the wasm is a separate file you must host, while the JS decoders ship inside your bundle.

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