Merge branch 'main' into uzu

packages/core/signal.mjs

@@ -1,6 +1,6 @@
 /*
 signal.mjs - continuous patterns
-Copyright (C) 2024 Strudel contributors - see <https://github.com/tidalcycles/strudel/blob/main/packages/core/signal.mjs>
+Copyright (C) 2024 Strudel contributors - see <https://codeberg.org/uzu/strudel/src/branch/main/packages/core/signal.mjs>
 This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
@@ -488,13 +488,34 @@ 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);
 };
 
 /**
@@ -508,6 +529,18 @@ 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")
+ *
+ */
+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)),