83 lines
2.2 KiB
Text
83 lines
2.2 KiB
Text
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#lang scribble/manual
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@(require (for-label racket))
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@title{IndexInBetween}
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Finds the (lowest) point in the Buffer at which the input signal lies in-between the two values@section{categories}
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UGens>Buffer
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@section{related}
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Classes/Index, Classes/IndexL, Classes/SequenceableCollection#indexInBetween
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@section{description}
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Finds the (lowest) point in the link::Classes/Buffer:: at which the input signal lies in-between the two values, and returns the index. The fractional part of the index is suitable for linearly interpolating between the buffer slot values.
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For example, if the Buffer contains [3, 21, 25, 26] and the input has the value 22, then the output will be 1.25, because the value 22 is in-between the values stored in indices 1 and 2 and in fact is one-quarter of the way along the interval between them.
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IndexInBetween is the complement of link::Classes/IndexL::.
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@section{classmethods}
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@section{method}
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ar, kr
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@section{argument}
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bufnum
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index of the buffer.
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@section{argument}
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in
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the input signal.
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@section{examples}
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@racketblock[
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(
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// autotune.
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{
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var index, in, autotuned, f0, fdiff;
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var scale = ([0, 1, 3, 4, 7, 11, 12] + 70).midicps;
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var buffer = scale.as(LocalBuf);
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in = Pulse.ar(MouseX.kr(scale.minItem, scale.maxItem)) * 0.1;
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f0 = Pitch.kr(in).at(0);
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index = IndexInBetween.kr(buffer, f0);
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fdiff = index.frac * (Index.kr(buffer, index + 1) - Index.kr(buffer, index));
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autotuned = PitchShift.ar(in, 0.1, 1 - (fdiff / f0), 0.01, 0.01);
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RLPF.ar(autotuned, [2000, 5000], 0.3)
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}.play;
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)
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b.free;
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// basic test.
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(
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{
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var index, f0, f1, f3;
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var buffer = [ 200, 210, 400, 430, 600, 800 ].as(LocalBuf);
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f0 = MouseX.kr(200, 900);
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index = IndexInBetween.kr(buffer, f0);
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f1 = IndexL.kr(buffer, index);
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SinOsc.ar([f0, f1]) * 0.1
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}.play;
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)
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// One way to map across from an arbitrary piecewise curve, onto another:
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// We use IndexInBetween to "unmap" your input into integer slots,
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// and then use IndexL to do the reverse, to "map" onto your other distribution.
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// This example maps a sort-of-exponential curve onto a sort-of-sinusoidal curve:
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~from = [1, 2, 4, 8, 16];
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~to = [0, 1, 0, -1, 0];
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(
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x = {
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IndexL.kr(~to.as(LocalBuf), IndexInBetween.kr(~from.as(LocalBuf),MouseX.kr(~from.first, ~from.last).poll).poll).poll
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}.play
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)
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::
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]
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