118 lines
2.2 KiB
Text
118 lines
2.2 KiB
Text
|
#lang scribble/manual
|
||
|
|
@(require (for-label racket))
|
||
|
|
|
||
|
|
@title{Sweep}
|
||
|
|
Triggered linear ramp@section{categories}
|
||
|
|
UGens>Triggers
|
||
|
|
|
||
|
|
@section{description}
|
||
|
|
|
||
|
|
|
||
|
|
Starts a linear raise by rate/sec from zero when trig input crosses from
|
||
|
|
non-positive to positive.
|
||
|
|
|
||
|
|
When rate == 1, Sweep may be used to get a continually-updating measurement
|
||
|
|
of the time (in seconds) since the last trigger.
|
||
|
|
|
||
|
|
|
||
|
|
@section{classmethods}
|
||
|
|
|
||
|
|
@section{private}
|
||
|
|
categories
|
||
|
|
|
||
|
|
@section{method}
|
||
|
|
ar, kr
|
||
|
|
|
||
|
|
@section{argument}
|
||
|
|
trig
|
||
|
|
|
||
|
|
triggers when trig input crosses from non-positive to positive.
|
||
|
|
|
||
|
|
|
||
|
|
@section{argument}
|
||
|
|
rate
|
||
|
|
|
||
|
|
rate/sec raise rate
|
||
|
|
|
||
|
|
|
||
|
|
@section{Examples}
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
@racketblock[
|
||
|
|
// using sweep to modulate sine frequency
|
||
|
|
(
|
||
|
|
{ var trig;
|
||
|
|
trig = Impulse.kr(MouseX.kr(0.5, 20, 1));
|
||
|
|
SinOsc.ar(Sweep.kr(trig, 700) + 500, 0, 0.2)
|
||
|
|
}.play;
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
// using sweep to index into a buffer
|
||
|
|
b = Buffer.read(s, Platform.resourceDir +/+ "sounds/a11wlk01.wav");
|
||
|
|
|
||
|
|
(
|
||
|
|
{ var trig;
|
||
|
|
trig = Impulse.kr(MouseX.kr(0.5, 10, 1));
|
||
|
|
BufRd.ar(1, b, Sweep.ar(trig, BufSampleRate.ir(0)))
|
||
|
|
}.play;
|
||
|
|
)
|
||
|
|
|
||
|
|
// backwards, variable offset
|
||
|
|
(
|
||
|
|
{ var trig, pos, rate;
|
||
|
|
trig = Impulse.kr(MouseX.kr(0.5, 10, 1));
|
||
|
|
rate = BufSampleRate.ir(0);
|
||
|
|
pos = Sweep.ar(trig, rate.neg) + (BufFrames.ir(0) * LFNoise0.kr(0.2));
|
||
|
|
BufRd.ar(1, b, pos)
|
||
|
|
}.play;
|
||
|
|
)
|
||
|
|
|
||
|
|
// raising rate
|
||
|
|
(
|
||
|
|
{ var trig, rate;
|
||
|
|
trig = Impulse.kr(MouseX.kr(0.5, 10, 1));
|
||
|
|
rate = Sweep.kr(trig, 2) + 0.5;
|
||
|
|
BufRd.ar(1, b, Sweep.ar(trig, BufSampleRate.ir(0) * rate))
|
||
|
|
}.play;
|
||
|
|
)
|
||
|
|
|
||
|
|
b.free
|
||
|
|
|
||
|
|
::
|
||
|
|
|
||
|
|
Sweep can be used as a resettable link::Classes/Phasor:: or link::Classes/Line:: - one that can start, pause, resume and stop. To get a resettable link::Classes/XLine:: behavior change the ]
|
||
|
|
|
||
|
|
@racketblock[linlin:: to ]
|
||
|
|
|
||
|
|
@racketblock[linexp:: in the SynthDef below.
|
||
|
|
]
|
||
|
|
|
||
|
|
@racketblock[
|
||
|
|
(
|
||
|
|
SynthDef(\lineReset, {|start= 0, end= 1, dur= 1, t_trig= 1, run= 1|
|
||
|
|
var phasor= (Sweep.ar(t_trig, 1/dur*run)).linlin(0, 1, start, end, \minmax);
|
||
|
|
phasor.poll;
|
||
|
|
Out.ar(0, SinOsc.ar(phasor, 0, 0.2));
|
||
|
|
}).add;
|
||
|
|
)
|
||
|
|
a= Synth(\lineReset, [\start, 400, \end, 800, \dur, 2])
|
||
|
|
a.set(\t_trig, 1)
|
||
|
|
a.set(\run, 0)
|
||
|
|
a.set(\run, 1)
|
||
|
|
a.set(\t_trig, 1)
|
||
|
|
a.free
|
||
|
|
|
||
|
|
//shorter duration and downwards...
|
||
|
|
a= Synth(\lineReset, [\start, 1000, \end, 500, \dur, 0.5])
|
||
|
|
a.set(\t_trig, 1)
|
||
|
|
a.set(\run, 0)
|
||
|
|
a.set(\run, 1)
|
||
|
|
a.set(\t_trig, 1)
|
||
|
|
a.free
|
||
|
|
::
|
||
|
|
]
|
||
|
|
|
||
|
|
|