feat: implement free-field CPU beamforming

2026-08-28 09:48:34 +09:00
parent 691a4b03ce
commit 6a1197d60e
15 changed files with 1148 additions and 4 deletions
@@ -0,0 +1,34 @@
+function mix32(value) {
+  let mixed = value >>> 0;
+  mixed ^= mixed >>> 16;
+  mixed = Math.imul(mixed, 0x7feb352d);
+  mixed ^= mixed >>> 15;
+  mixed = Math.imul(mixed, 0x846ca68b);
+  mixed ^= mixed >>> 16;
+  return mixed >>> 0;
+}
+
+export function hashString(value) {
+  let hash = 2166136261;
+  for (let index = 0; index < value.length; index += 1) {
+    hash ^= value.charCodeAt(index);
+    hash = Math.imul(hash, 16777619);
+  }
+  return hash >>> 0;
+}
+
+export function whiteNoiseAt(seed, sampleIndex) {
+  const mixed = mix32((seed >>> 0) ^ Math.imul(sampleIndex + 1, 0x9e3779b1));
+  return (mixed / 0xffffffff) * 2 - 1;
+}
+
+export function pinkNoiseAt(seed, sampleIndex) {
+  let total = 0;
+  let weight = 0;
+  for (let octave = 0; octave < 8; octave += 1) {
+    const octaveWeight = 1 / (octave + 1);
+    total += whiteNoiseAt(seed + octave * 0x1f123bb5, sampleIndex >> octave) * octaveWeight;
+    weight += octaveWeight;
+  }
+  return total / weight;
+}