waw-rs

waw-rs should help you create Web Audio Worklets using Rust, without crying.

See WebAssembly/Rust Tutorial: Pitch-perfect Audio Processing

This is all very experimental.

Usage

To use waw-rs in your project, add it as a dependency in your Cargo.toml:

waw = { git = "https://github.com/Marcel-G/waw-rs" }

You will need to setup an xtask to build the project, see xtask-waw.

Then, in your Rust code, simply implement the AudioModule trait and call the waw::main! macro on your struct:

src/lib.rs

use waw::{
  worklet::{ AudioModule, Emitter },
  buffer::{ AudioBuffer, ParamBuffer }
};

struct MyWorklet;

impl AudioModule for MyWorklet {
  fn create(
    _initial_state: Option<Self::InitialState>,
    _emitter: Emitter<Self::Event>
  ) -> Self { MyWorklet }
  fn process(&mut self, audio: &mut AudioBuffer, params: &ParamBuffer<Self::Param>) {
    // Implement process
  }
}

waw::main!(MyWorklet);

Run the build using the xtask command

cargo xtask dist

They can then be used from JavaScript:

import init, { init_worklet, MyWorklet } from "./pkg/waw-demo";
import worklet_url from "./pkg/waw-demo.worklet.js?url&worker";
// Note: waw-demo.worklet.js must be loaded as a URL - bundlers may need different config for this

const main = async () => {
  // Init WASM on the main thread
  await init();

  // Create an audio context
  const context = new AudioContext();

  // Init WASM on the audio worklet thread
  await init_worklet(context, worklet_url);

  // Call create on the generated worklet node
  const worklet = await MyWorklet.create(context);

  // Connect the audio node to WebAudio graph
  worklet.node().connect(context.destination);

  // Wait for some interaction on the page before starting the audio
  const handle_interaction = () => {
    void context?.resume();
  };
  document.addEventListener("click", handle_interaction, { once: true });
};

main();

See the demo project for a full example.

Links

• wasm-bindgen WASM audio worklet