108 lines
1.7 KiB
Racket
108 lines
1.7 KiB
Racket
#lang scribble/manual
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@(require (for-label racket))
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@title{Pbrown}
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brownian motion pattern@section{related}
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Classes/BrownNoise, Classes/Pgbrown
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@section{categories}
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Streams-Patterns-Events>Patterns>Random
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@section{description}
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Returns a stream that behaves like a brownian motion.
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@section{ClassMethods}
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@section{method}
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new
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@section{argument}
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lo
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lower boundary of values.
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@section{argument}
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hi
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upper boundary of values.
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@section{argument}
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step
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maximum change per step - the distribution is xrand2.
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@section{argument}
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length
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number of values produced.
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@section{Examples}
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@racketblock[
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(
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var a;
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a = Pbrown(0.0, 1.0, 0.1, inf);
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c = a.asStream.nextN(500);
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w = Window.new("Pbrown", Rect(10, 10, 540, 800));
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// plot the values
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c.plot(bounds: Rect(10, 10, 520, 380), discrete: true, parent: w);
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// a histogram of the values
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c.histo(500).plot(bounds: Rect(10, 410, 520, 380), parent: w);
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)
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(
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var a;
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a = Pbrown(0.0, 1.0, 0.2, inf);
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a.asStream.nextN(1000).plot2;
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)
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::
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]
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@racketblock[
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// sound example
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(
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SynthDef(\help_sinegrain,
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{ arg out=0, freq=440, sustain=0.05;
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var env;
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env = EnvGen.kr(Env.perc(0.01, sustain, 0.2), doneAction: Done.freeSelf);
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Out.ar(out, SinOsc.ar(freq, 0, env))
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}).add;
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)
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(
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var a;
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a = Pbrown(0.0, 1.0, 0.1, inf).asStream;
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{
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loop {
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Synth(\help_sinegrain, [\freq, a.next * 600 + 300]);
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0.02.wait;
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}
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}.fork;
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)
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// parallel browninan motions
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(
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var a, x, f;
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a = Pbrown(0.0, 1.0, 0.1, inf);
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f = { |pattern, dt=0.02, min=300, max=900|
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{
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var x = pattern.asStream;
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loop {
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Synth.grain(\help_sinegrain, [\freq, x.next.linexp(0, 1, min, max), \sustain, dt]);
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dt.wait;
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}
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}.fork;
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}.flop;
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// 3 parallel motions
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f.(a, [0.02, 0.08, 0.16]);
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)
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::
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]
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