@draco-rust/encoder

Encodes meshes and point clouds to Draco (.drc) in WebAssembly. It is part of draco-rust, a safe Rust port of Google's Draco, and with default options writes the same bytes as Google's encoder. It is not affiliated with Google. To decode, use @draco-rust/decoder.

~133 KiB gzip.

Usage

import init, { encode_draco } from "@draco-rust/encoder";

await init();
const result = encode_draco(
  { positions, indices, normals, uvs, colors },  // typed arrays; all but positions optional
  { position_bits: 14, normal_bits: 10, texcoord_bits: 12, encoding_speed: 5, decoding_speed: 5 },
);
if (!result.success) throw new Error(result.error);
const drc = result.bytes; // Uint8Array

positions is a Float32Array of xyz triples and indices a Uint32Array of triangle corners. Leave indices out, or set point_cloud: true, to write a point cloud. Two options act on point clouds only:

• prediction_search chooses each attribute's prediction by its estimated cost.
• spatial_point_order orders the points along a Hilbert curve.

Both write smaller files, at the cost of output no longer byte-identical to Google's encoder.

On workers

@draco-rust/encoder/pool encodes on workers, so a large mesh does not block the calling thread:

import { createPool } from "@draco-rust/encoder/pool";

const pool = createPool({ workers: 2 });
const result = await pool.encode(mesh, { position_bits: 14 }); // what encode_draco returns
pool.dispose();

The workers start as work arrives, and the wasm is compiled once for all of them. Inputs are copied to the worker, or handed over with { transfer: true }; { signal } takes an AbortSignal, which rejects the promise at once. A task a worker has started still runs to its end and its result is dropped. With workers: 0, or where there are no workers, the pool runs on the calling thread. It works on Web Workers, Node's worker threads (Node 20.16 and later) and from a CDN, as the decoder's does.

For loading from a CDN or in Node, see the decoder's README; the same init options apply, with @draco-rust/encoder/index_bg.wasm as the file.

Licensed under Apache-2.0, like Draco.

This build

@draco-rust/[email protected] was built from draco-rust commit 4b72cfc8, with draco-core 2.3.2, draco-io 0.6.0, draco-gltf 0.7.0.