strudel/packages/wam/index.mjs

import { register, Pattern, toMidi, valueToMidi } from '@strudel.cycles/core';
import { getAudioContext } from '@strudel.cycles/webaudio';
import { initializeWamHost } from '@webaudiomodules/sdk';

// this is a map of all loaded WebAudioModules
let wams = {};

// this is a map of all WebAudioModule instances (possibly more than one per WAM)
let wamInstances = {};
export const getWamInstances = () => wamInstances;

// has the WAM host been initialized?
let initialized = false;

// host groups of WAMs can interact with one another, but not directly across groups
const hostGroupId = 'strudel';

export const loadWAM = async function (name, url, what) {
  if (!initialized) {
    await initializeWamHost(getAudioContext(), hostGroupId);
    initialized = true;
  }

  if (wamInstances[name]) {
    return wamInstances[name];
  }

  if (!wams[url]) {
    const { default: WAM } = await import(
      /* @vite-ignore */
      url
    );

    wams[url] = WAM;
  }

  const instance = new wams[url](hostGroupId, getAudioContext());

  await instance.initialize();

  instance.audioNode.connect(getAudioContext().destination);

  wamInstances[name] = instance;

  return instance;
};

export const loadwam = loadWAM;
export const loadWam = loadWAM;

export const wam = register('wam', function (name, pat) {
  return pat.onTrigger((time, hap) => {
    let i = wamInstances[name];

    if (!i) {
      return;
    }

    let note = toMidi(hap.value.note);
    let velocity = hap.context?.velocity ?? 0.75;
    let endTime = time + hap.duration.valueOf();

    i.audioNode.scheduleEvents({
      type: 'wam-midi',
      data: { bytes: [0x90, note, velocity] },
      time: time,
    });

    i.audioNode.scheduleEvents({
      type: 'wam-midi',
      data: { bytes: [0x80, note, 0] },
      time: endTime,
    });
  });
});

export const param = register('param', function (wam, param, pat) {
  return pat.onTrigger((time, hap) => {
    let i = wamInstances[wam];
    if (!i) {
      return;
    }
    i.audioNode.scheduleEvents({
      time: time,
      type: 'wam-automation',
      data: {
        id: param,
        normalized: false,
        value: hap.value,
      },
    });
  }, false);
});