add basic csound output

packages/csound/csound.mjs

@@ -0,0 +1,119 @@
+import { getFrequency, logger, Pattern } from '@strudel.cycles/core';
+import { getAudioContext } from '@strudel.cycles/webaudio';
+import csd from './project.csd?raw';
+// import livecodeOrc from './livecode.orc?raw';
+import presetsOrc from './presets.orc?raw';
+
+let csoundLoader, _csound;
+
+// triggers given instrument name using csound.
+Pattern.prototype._csound = function (instrument) {
+  instrument = instrument || 'triangle';
+  init(); // not async to support csound inside other patterns + to be able to call pattern methods after it
+  // TODO: find a alternative way to wait for csound to load (to wait with first time playback)
+  return this.onTrigger((time, hap) => {
+    if (!_csound) {
+      logger('[csound] not loaded yet', 'warning');
+      return;
+    }
+    if (typeof hap.value !== 'object') {
+      throw new Error('csound only support objects as hap values');
+    }
+    let { gain = 0.8 } = hap.value;
+    gain *= 0.2;
+
+    const freq = Math.round(getFrequency(hap));
+    const controls = Object.entries({ ...hap.value, freq })
+      .flat()
+      .join('/');
+    // TODO: find out how to send a precise ctx based time
+    // http://www.csounds.com/manual/html/i.html
+    const params = [
+      `"${instrument}"`, // p1: instrument name
+      time - getAudioContext().currentTime, //.toFixed(precision), // p2: starting time in arbitrary unit called beats
+      hap.duration + 0, // p3: duration in beats
+      // instrument specific params:
+      freq, //.toFixed(precision), // p4: frequency
+      gain, // p5: gain
+      `"${controls}"`, // p6 controls as string (like superdirt osc message)
+    ];
+    const msg = `i ${params.join(' ')}`;
+    _csound.inputMessage(msg);
+  });
+};
+
+// initializes csound + can be used to reevaluate given instrument code
+export async function csound(code = '') {
+  await init();
+  if (code) {
+    code = `${code}`;
+    //     ^       ^
+    // wrapping in backticks makes sure it works when calling as templated function
+    await _csound?.evalCode(code);
+  }
+}
+
+Pattern.prototype.define('csound', (a, pat) => pat.csound(a), { composable: false, patternified: true });
+
+function eventLogger(type, args) {
+  const [msg] = args;
+  if (
+    type === 'message' &&
+    (['[commit: HEAD]'].includes(msg) ||
+      msg.startsWith('--Csound version') ||
+      msg.startsWith('libsndfile') ||
+      msg.startsWith('sr =') ||
+      msg.startsWith('0dBFS') ||
+      msg.startsWith('audio buffered') ||
+      msg.startsWith('writing') ||
+      msg.startsWith('SECTION 1:'))
+  ) {
+    // ignore
+    return;
+  }
+  let logType = 'info';
+  if (msg.startsWith('error:')) {
+    logType = 'error';
+  }
+  logger(`[csound] ${msg || ''}`, logType);
+}
+
+async function load() {
+  if (window.__csound__) {
+    // allows using some other csound instance
+    _csound = window.__csound__;
+  } else {
+    const { Csound } = await import('@csound/browser');
+    _csound = await Csound({ audioContext: getAudioContext() });
+  }
+  _csound.removeAllListeners('message');
+  ['message'].forEach((k) => _csound.on(k, (...args) => eventLogger(k, args)));
+  await _csound.setOption('-m0d'); // see -m flag https://csound.com/docs/manual/CommandFlags.html
+  await _csound.setOption('--sample-accurate');
+  await _csound.compileCsdText(csd);
+  // await _csound.compileOrc(livecodeOrc);
+  await _csound.compileOrc(presetsOrc);
+  await _csound.start();
+  return _csound;
+}
+
+async function init() {
+  csoundLoader = csoundLoader || load();
+  return csoundLoader;
+}
+
+let orcCache = {};
+export async function loadOrc(url) {
+  await init();
+  if (typeof url !== 'string') {
+    throw new Error('loadOrc: expected url string');
+  }
+  if (url.startsWith('github:')) {
+    const [_, path] = url.split('github:');
+    url = `https://raw.githubusercontent.com/${path}`;
+  }
+  if (!orcCache[url]) {
+    orcCache[url] = await fetch(url).then((res) => res.text());
+  }
+  await _csound.compileOrc(orcCache[url]);
+}