rsc3/doc-schelp/HelpSource/Classes/Pevent.scrbl

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2022-08-24 13:53:18 +00:00
#lang scribble/manual
@(require (for-label racket))
@title{Pevent}
Provide an inval for an event stream.@section{related}
Classes/Pkey, Classes/Pchain
@section{categories}
Streams-Patterns-Events>Patterns
This pattern is mainly used in two cases:
@section{definitionlist}
## using an event pattern as a stream directly
||
@racketblock[
a = Pbind(\note, Prand([1, 2, 3], inf)).asStream;
a.next; // returns nil
a = Pevent(Pbind(\note, Prand([1, 2, 3], inf))).asStream;
a.next; // returns an event
::
## setting some default values before they are processed by the pattern
||
]
@racketblock[
Pevent(Pbind(\harmonic, Pseq([24, 25, 29, 30], inf)), (octave: 3, dur: 0.2)).trace.play;
::
::
Pevent is a simpler form of link::Classes/Pchain::, so that these are equivalent:
]
@racketblock[
Pevent(pattern, event)
Pchain(pattern, event)
pattern <> event
::
By contrast to Pchain, Pevent uses an link::Classes/Event#*default:: if nothing is provided.
]
@section{ClassMethods}
@section{method}
new
@section{argument}
pattern
pattern or stream that returns or modifies events.
@section{argument}
event
an event with objects to embed. If none is provided, it uses link::Classes/Event#*default::.
@section{examples}
@racketblock[
(
SynthDef(\help_sinegrain,
{ arg out=0, freq=440, sustain=0.05;
var env;
env = EnvGen.kr(Env.perc(0.01, sustain, 0.2), doneAction: Done.freeSelf);
Out.ar(out, SinOsc.ar(freq, 0, env))
}).add;
a = Pn(
Plazy({
Pbind(
\instrument, \help_sinegrain,
\freq, Pgeom(rrand(200, 600), rrand(1.001, 1.01), rrand(10, 100)).wrap(100, 15000),
\dur, Pgeom(rrand(0.2, 0.3), rrand(0.99, 0.92))
)
})
);
Tdef(\x, {
var str = Pevent(a).asStream, event;
loop {
event = str.next;
if(event[\freq] % 50 < 20) { event[\freq] = event[\freq] * [1, 1.2, 1.5] };
event.play;
event[\dur].wait;
}
}).play;
)
::
]