mosfez-faust

Makes dynamic compilation of Faust on the web a little easier, and has a dev project to run values through dsp offline, and preview dsp live. It's an opinionated version of some parts of Faust for webaudio, mostly just the Web Assembly Faust compiler, wrapped up in a library that has:

• full typescript compatibility
• ESM exports, so no need to add <script> tags
• have any async functions chain seamlessly off any prior initialisation steps, so if a required resource is not yet ready, the API function simply waits until it is ready
• error reporting is more idiomatic for JavaScript - error objects are thrown containing details of the problem when compilation does not work

See the dev project - but keep in mind it's intended to be used locally.

Note: "opinionated" means this library has a much narrower set of concerns than the original Faust webaudio API it's using. This is mainly just for compilation on the web, playback using AudioWorket nodes, no in-built-polyphonic compilation. Some compilation options may be inaccessible via this API.

Installation

npm install mosfez-faust or yarn add mosfez-faust

Then you'll need to copy the files from node_modules/mosfez-faust/public and put it in your projects public-facing root directory that will be accessible once deployed. e.g. if you are using Vite, put them in your Vite project's public directory. This library will make a request for libfaust-wasm.wasm and libfaust-wasm.data when it starts up, and will not work if those files can't be found.

Usage

import { compile } from "mosfez-faust/faust";
import { touchStart } from "mosfez-faust/touch-start";

const audioContext = new window.AudioContext();
touchStart(audioContext);

async function startSines() {
  const dsp = `
    import("stdfaust.lib");
    process = os.osc(440.0),os.osc(441.0);
  `;

  const node = await compile(audioContext, dsp);
  node.connect(audioContext.destination);
}

Or to separately create a factory and worklet nodes:

import { compileFactory } from "mosfez-faust/faust";
import { touchStart } from "mosfez-faust/touch-start";

const audioContext = new window.AudioContext();
touchStart(audioContext);

async function startSines() {
  const dsp = `
    import("stdfaust.lib");
    process = os.osc(440.0),os.osc(441.0);
  `;

  const factory = await compileFactory(dsp);
  const node = await factory.createNode(audioContext);
  node.connect(audioContext.destination);
}

Also some general purpose web audio conversion utilities can be found at:

import { * as conversions } from "mosfez-faust/convert";

See source code for details.

The dev project

The /dev directory contains a dev project that uses Vite and allows Faust DSP development in an IDE, while hot realoading and displaying and playing the results of your DSP changes. After cloning the repo, run yarn prep then cd dev, then yarn dev to use the project.

DSP definitions can be added and browsed to. There are two types, offline and live.

• Offline DSP is compiled on page load or file save, and values specified in the dsp definition are passed through the faust DSP and logged to the console. This makes for a very deliberate DSP development experience, where you can even define your expected output and console messages will indicate if your DSP produces the correct result.
• Live DSP is compiled on page load or file save, and is immediately started and connected to an audiocontext in the browser so you can hear the result live.

Developing this library

This library is written in typescript, using modified code from Faust's repo and wrapping that in a typical typescript library "wrapper". It's bundled with rollup, formatted with prettier, linted with eslint and tested with jest.

You will need node@16 or greater and yarn@1 installed globally. Clone the repo and run yarn prep to install deps and build. Then you can run:

• yarn build to build the *.ts source files into *.js files and *.d.ts type files in /dist.
• yarn test to run tests using jest (none yet).
• yarn pretty to run the auto-formatter prettier.
• yarn lint to run the linter eslint.
• cd dev && yarn dev to run the dev project