berlin

packages/core/signal.mjs

@@ -486,13 +486,34 @@ export const wchooseCycles = (...pairs) => _wchooseWith(rand.segment(1), ...pair
 
 export const wrandcat = wchooseCycles;
 
-// this function expects pat to be a pattern of floats...
-export const perlinWith = (pat) => {
-  const pata = pat.fmap(Math.floor);
-  const patb = pat.fmap((t) => Math.floor(t) + 1);
+function _perlin(t) {
+  let ta = Math.floor(t);
+  let tb = ta + 1;
   const smootherStep = (x) => 6.0 * x ** 5 - 15.0 * x ** 4 + 10.0 * x ** 3;
   const interp = (x) => (a) => (b) => a + smootherStep(x) * (b - a);
-  return pat.sub(pata).fmap(interp).appBoth(pata.fmap(timeToRand)).appBoth(patb.fmap(timeToRand));
+  const v = interp(t - ta)(timeToRand(ta))(timeToRand(tb));
+  return v;
+}
+export const perlinWith = (tpat) => {
+  return tpat.fmap(_perlin);
+};
+
+function _berlin(t) {
+  const prevRidgeStartIndex = Math.floor(t);
+  const nextRidgeStartIndex = prevRidgeStartIndex + 1;
+
+  const prevRidgeBottomPoint = timeToRand(prevRidgeStartIndex);
+  const nextRidgeTopPoint = timeToRand(nextRidgeStartIndex) + prevRidgeBottomPoint;
+
+  const currentPercent = (t - prevRidgeStartIndex) / (nextRidgeStartIndex - prevRidgeStartIndex);
+  const interp = (a, b, t) => {
+    return a + (b - a) * t;
+  };
+  return interp(prevRidgeBottomPoint, nextRidgeTopPoint, currentPercent) / 2;
+}
+
+export const berlinWith = (tpat) => {
+  return tpat.fmap(_berlin);
 };
 
 /**
@@ -506,6 +527,18 @@ export const perlinWith = (pat) => {
  */
 export const perlin = perlinWith(time.fmap((v) => Number(v)));
 
+/**
+ * Generates a continuous pattern of [berlin noise](conceived by Jame Coyne and Jade Rowland as a joke but turned out to be surprisingly cool and useful,
+ * like perlin noise but with sawtooth waves), in the range 0..1.
+ *
+ * @name berlin
+ * @example
+ * // ascending arpeggios
+ * $: n("0!16".add(berlin.fast(4).mul(14))).scale("d:minor")._pianoroll()
+ *
+ */
+export const berlin = berlinWith(time.fmap((v) => Number(v)));
+
 export const degradeByWith = register(
   'degradeByWith',
   (withPat, x, pat) => pat.fmap((a) => (_) => a).appLeft(withPat.filterValues((v) => v > x)),

packages/superdough/worklets.mjs

@@ -882,7 +882,6 @@ class ByteBeatProcessor extends AudioWorkletProcessor {
       const funcValue = this.func(local_t);
       let signal = (funcValue & 255) / 127.5 - 1;
       const out = signal * 0.2;
-
       for (let c = 0; c < output.length; c++) {
         //prevent speaker blowout via clipping if threshold exceeds
         output[c][i] = clamp(out, -0.4, 0.4);

test/__snapshots__/examples.test.mjs.snap

@@ -1051,6 +1051,8 @@ exports[`runs examples > example "begin" example index 0 1`] = `
 ]
 `;
 
+exports[`runs examples > example "berlin" example index 0 1`] = `[]`;
+
 exports[`runs examples > example "binary" example index 0 1`] = `
 [
   "[ 0/1 → 1/3 | s:hh ]",