first draft of soundMap to register keys for s

+ refactor sampler to use it
+ refactor synth to use it
+ add 'source' control
+ wip: samples tab
+ wip: webadirt ?
+ wip: soundfonts

packages/webaudio/helpers.mjs

@@ -0,0 +1,47 @@
+import { getAudioContext } from './webaudio.mjs';
+
+export function gainNode(value) {
+  const node = getAudioContext().createGain();
+  node.gain.value = value;
+  return node;
+}
+
+export const getOscillator = ({ s, freq, t, duration, release }) => {
+  // make oscillator
+  const o = getAudioContext().createOscillator();
+  o.type = s || 'triangle';
+  o.frequency.value = Number(freq);
+  o.start(t);
+  o.stop(t + duration + release);
+  return o;
+};
+
+export const getADSR = (attack, decay, sustain, release, velocity, begin, end) => {
+  const gainNode = getAudioContext().createGain();
+  gainNode.gain.setValueAtTime(0, begin);
+  gainNode.gain.linearRampToValueAtTime(velocity, begin + attack); // attack
+  gainNode.gain.linearRampToValueAtTime(sustain * velocity, begin + attack + decay); // sustain start
+  gainNode.gain.setValueAtTime(sustain * velocity, end); // sustain end
+  gainNode.gain.linearRampToValueAtTime(0, end + release); // release
+  // for some reason, using exponential ramping creates little cracklings
+  /* let t = begin;
+  gainNode.gain.setValueAtTime(0, t);
+  gainNode.gain.exponentialRampToValueAtTime(velocity, (t += attack));
+  const sustainGain = Math.max(sustain * velocity, 0.001);
+  gainNode.gain.exponentialRampToValueAtTime(sustainGain, (t += decay));
+  if (end - begin < attack + decay) {
+    gainNode.gain.cancelAndHoldAtTime(end);
+  } else {
+    gainNode.gain.setValueAtTime(sustainGain, end);
+  }
+  gainNode.gain.exponentialRampToValueAtTime(0.001, end + release); // release */
+  return gainNode;
+};
+
+export const getFilter = (type, frequency, Q) => {
+  const filter = getAudioContext().createBiquadFilter();
+  filter.type = type;
+  filter.frequency.value = frequency;
+  filter.Q.value = Q;
+  return filter;
+};