Merge pull request #219 from tidalcycles/webaudio-output

encapsulate webaudio output

packages/webaudio/webaudio.mjs

@@ -22,6 +22,21 @@ export const getAudioContext = () => {
   return audioContext;
 };
 
+let destination;
+const getDestination = () => {
+  const ctx = getAudioContext();
+  if (!destination) {
+    destination = ctx.createGain();
+    destination.connect(ctx.destination);
+  }
+  return destination;
+};
+
+export const panic = () => {
+  getDestination().gain.linearRampToValueAtTime(0, getAudioContext().currentTime + 0.01);
+  destination = null;
+};
+
 const getFilter = (type, frequency, Q) => {
   const filter = getAudioContext().createBiquadFilter();
   filter.type = type;
@@ -87,7 +102,7 @@ const getSampleBufferSource = async (s, n, note) => {
   }
   const bank = samples?.[s];
   if (!bank) {
-    throw new Error('sample not found:', s, 'try one of ' + Object.keys(samples));
+    throw new Error(`sample not found: "${s}", try one of ${Object.keys(samples).join(', ')}`);
   }
   if (typeof bank !== 'object') {
     throw new Error('wrong format for sample bank:', s);
@@ -147,21 +162,27 @@ function getWorklet(ac, processor, params) {
   return node;
 }
 
+if (typeof window !== 'undefined') {
   try {
     loadWorklets();
   } catch (err) {
     console.warn('could not load AudioWorklet effects coarse, crush and shape', err);
   }
+}
 
 const cutGroups = [];
 
-Pattern.prototype.out = function () {
+// export const webaudioOutput = async (t, hap, ct, cps) => {
-  return this.onTrigger(async (t, hap, ct, cps) => {
+export const webaudioOutput = async (hap, deadline, hapDuration) => {
-    const hapDuration = hap.duration / cps;
   try {
     const ac = getAudioContext();
+    if (typeof hap.value !== 'object') {
+      throw new Error(
+        `hap.value ${hap.value} is not supported by webaudio output. Hint: append .note() or .s() to the end`,
+      );
+    }
     // calculate correct time (tone.js workaround)
-      t = ac.currentTime + t - ct;
+    let t = ac.currentTime + deadline;
     // destructure value
     let {
       freq,
@@ -308,17 +329,17 @@ Pattern.prototype.out = function () {
       panner.pan.value = 2 * pan - 1;
       chain.push(panner);
     }
-      // master out
-      /* const master = ac.createGain();
-    master.gain.value = 0.8 * gain;
-    chain.push(master); */
-      chain.push(ac.destination);
     // connect chain elements together
     chain.slice(1).reduce((last, current) => last.connect(current), chain[0]);
+    chain[chain.length - 1].connect(getDestination());
     // disconnect all nodes when source node has ended:
     chain[0].onended = () => chain.forEach((n) => n.disconnect());
   } catch (e) {
     console.warn('.out error:', e);
   }
-  });
+};
+
+Pattern.prototype.out = function () {
+  // TODO: refactor (t, hap, ct, cps) to (hap, deadline, duration) ?
+  return this.onTrigger((t, hap, ct, cps) => webaudioOutput(hap, t - ct, hap.duration / cps));
 };