add superdough package

packages/superdough/synth.mjs

@@ -0,0 +1,44 @@
+import { midiToFreq, noteToMidi } from './util.mjs';
+import { registerSound } from './superdough.mjs';
+import { getOscillator, gainNode, getEnvelope } from './helpers.mjs';
+
+export function registerSynthSounds() {
+  ['sine', 'square', 'triangle', 'sawtooth'].forEach((wave) => {
+    registerSound(
+      wave,
+      (t, value, onended) => {
+        // destructure adsr here, because the default should be different for synths and samples
+        const { attack = 0.001, decay = 0.05, sustain = 0.6, release = 0.01 } = value;
+        let { n, note, freq } = value;
+        // with synths, n and note are the same thing
+        n = note || n || 36;
+        if (typeof n === 'string') {
+          n = noteToMidi(n); // e.g. c3 => 48
+        }
+        // get frequency
+        if (!freq && typeof n === 'number') {
+          freq = midiToFreq(n); // + 48);
+        }
+        // maybe pull out the above frequency resolution?? (there is also getFrequency but it has no default)
+        // make oscillator
+        const { node: o, stop } = getOscillator({ t, s: wave, freq });
+        const g = gainNode(0.3);
+        // envelope
+        const { node: envelope, stop: releaseEnvelope } = getEnvelope(attack, decay, sustain, release, 1, t);
+        o.onended = () => {
+          o.disconnect();
+          g.disconnect();
+          onended();
+        };
+        return {
+          node: o.connect(g).connect(envelope),
+          stop: (releaseTime) => {
+            releaseEnvelope(releaseTime);
+            stop(releaseTime + release);
+          },
+        };
+      },
+      { type: 'synth', prebake: true },
+    );
+  });
+}