diff --git a/strudel.mjs b/strudel.mjs index 0201e721..a0a200de 100644 --- a/strudel.mjs +++ b/strudel.mjs @@ -148,7 +148,7 @@ class TimeSpan { return result } - get midpoint() { + midpoint() { return(this.begin.add((this.end.sub(this.begin)).div(Fraction(2)))) } @@ -671,6 +671,32 @@ function steady(value) { return new Pattern(span => Hap(undefined, span, value)) } +export const signal = func => { + const query = span => [new Hap(undefined, span, func(span.midpoint()))] + return new Pattern(query) +} + +const _toBipolar = pat => pat.fmap(x => (x * 2) - 1) +const _fromBipolar = pat => pat.fmap(x => (x + 1) / 2) + +export const sine2 = signal(t => Math.sin(Math.PI * 2 * t)) +export const sine = _fromBipolar(sine2) + +export const cosine2 = sine2._early(0.25) +export const cosine = sine._early(0.25) + +export const saw = signal(t => t % 1) +export const saw2 = _toBipolar(saw) + +export const isaw = signal(t => 1 - (t % 1)) +export const isaw2 = _toBipolar(isaw) + +export const tri2 = fastcat(isaw2, saw2) +export const tri = fastcat(isaw, saw) + +export const square = signal(t => Math.floor((t*2) % 2)) +export const square2 = _toBipolar(square) + function reify(thing) { // Tunrs something into a pattern, unless it's already a pattern if (thing?.constructor?.name == "Pattern") { diff --git a/test/pattern.test.mjs b/test/pattern.test.mjs index c6986538..f6180a80 100644 --- a/test/pattern.test.mjs +++ b/test/pattern.test.mjs @@ -2,7 +2,7 @@ import Fraction from 'fraction.js' import { strict as assert } from 'assert'; -import {TimeSpan, Hap, Pattern, pure, stack, fastcat, slowcat, cat, sequence, polyrhythm, silence, fast, timeCat,add,sub,mul,div} from "../strudel.mjs"; +import {TimeSpan, Hap, Pattern, pure, stack, fastcat, slowcat, cat, sequence, polyrhythm, silence, fast, timeCat,add,sub,mul,div,saw,saw2,isaw,isaw2,sine,sine2,square,square2,tri,tri2} from "../strudel.mjs"; //import { Time } from 'tone'; import pkg from 'tone'; const { Time } = pkg; @@ -307,4 +307,26 @@ describe('Pattern', function() { ) }) }) + describe('signal()', function() { + it('Can make saw/saw2', function() { + assert.deepStrictEqual( + saw.struct(true,true,true,true).firstCycle, + sequence(1/8,3/8,5/8,7/8).firstCycle + ) + assert.deepStrictEqual( + saw2.struct(true,true,true,true).firstCycle, + sequence(-3/4,-1/4,1/4,3/4).firstCycle + ) + }) + it('Can make isaw/isaw2', function() { + assert.deepStrictEqual( + isaw.struct(true,true,true,true).firstCycle, + sequence(7/8,5/8,3/8,1/8).firstCycle + ) + assert.deepStrictEqual( + isaw2.struct(true,true,true,true).firstCycle, + sequence(3/4,1/4,-1/4,-3/4).firstCycle + ) + }) + }) })