Add generative garden audio

src/audio/noise-burst-player.ts

@@ -0,0 +1,64 @@
+import { clamp } from '../utils/math';
+import type { GardenAudioGraph } from './garden-audio-graph';
+import type { NoiseBurst } from './garden-audio-types';
+
+const noiseBurstTuning = {
+  attackSeconds: 0.004,
+  filterQ: 1.4,
+  offsetRandomSeconds: 0.4,
+  scheduleAheadSeconds: 0.002,
+  silentGain: 0.0001,
+  filterType: 'bandpass',
+} as const;
+
+export class NoiseBurstPlayer {
+  public constructor(private readonly graph: GardenAudioGraph) {}
+
+  public play({ startTime, durationSeconds, gain, filterHz, pan }: NoiseBurst): void {
+    const { context, noiseBus, noiseBuffer } = this.graph;
+    if (!context || !noiseBus || !noiseBuffer) {
+      return;
+    }
+
+    const scheduledStart = Math.max(
+      context.currentTime + noiseBurstTuning.scheduleAheadSeconds,
+      startTime
+    );
+    const source = context.createBufferSource();
+    const filter = context.createBiquadFilter();
+    const envelope = context.createGain();
+    const panner = context.createStereoPanner();
+    const stopAt = scheduledStart + durationSeconds;
+
+    source.buffer = noiseBuffer;
+    filter.type = noiseBurstTuning.filterType;
+    filter.frequency.setValueAtTime(filterHz, scheduledStart);
+    filter.Q.value = noiseBurstTuning.filterQ;
+    envelope.gain.setValueAtTime(noiseBurstTuning.silentGain, scheduledStart);
+    envelope.gain.exponentialRampToValueAtTime(
+      Math.max(noiseBurstTuning.silentGain, gain),
+      scheduledStart + noiseBurstTuning.attackSeconds
+    );
+    envelope.gain.exponentialRampToValueAtTime(noiseBurstTuning.silentGain, stopAt);
+    panner.pan.setValueAtTime(clamp(pan, -1, 1), scheduledStart);
+    source.connect(filter);
+    filter.connect(envelope);
+    envelope.connect(panner);
+    panner.connect(noiseBus);
+    const maxOffsetSeconds = Math.max(0, noiseBuffer.duration - durationSeconds);
+    const offsetSeconds =
+      Math.random() * Math.min(noiseBurstTuning.offsetRandomSeconds, maxOffsetSeconds);
+    source.start(scheduledStart, offsetSeconds);
+    source.stop(stopAt);
+    source.addEventListener(
+      'ended',
+      () => {
+        source.disconnect();
+        filter.disconnect();
+        envelope.disconnect();
+        panner.disconnect();
+      },
+      { once: true }
+    );
+  }
+}