rsc3/doc-schelp/HelpSource/Tutorials/JITLib/recursive_phrasing.scrbl

#lang scribble/manual
@(require (for-label racket))

@title{recursive_phrasing}
 Recursive phrases and granular composite sounds@section{categories}
  Libraries>JITLib>Tutorials
@section{related}
  Overviews/JITLib, Classes/Pdef, Classes/PlazyEnvirN

Pdef can be used as a global storage for event patterns. Here a way is provided by which these definitions can be used as an instrument that consists of several events (a emphasis::phrase::), such as a cloud of short grains. Furthermore, this scheme can be applied recursively, so that structures like a cloud of clouds can be constructed.

When the event type 
@racketblock[\phrase:: is passed in, the event looks for a pattern in ]

@racketblock[Pdef.all:: if it can find a definition.
]
@section{list}
 
## if it finds one it plays this pattern in the context of the outer pattern's event.
## f there is no definition to be found there, it uses a link::Classes/SynthDef:: with this name, if present.
::

When passing a emphasis::function:: to Pdef it creates a PlazyEnvirN internally. Its function is evaluated in the context of the input event (see link::Classes/PlazyEnvirN::) which should return a pattern or a stream. Note that this doesn't allow the usual access of the outer environment from within the function.


@racketblock[
(
s.boot;

SynthDef(\pgrain,
	{ arg out = 0, freq=800, sustain=0.001, amp=0.5, pan = 0;
		var window;
		window = Env.sine(sustain, amp * AmpCompA.kr(freq));
		Out.ar(out,
			Pan2.ar(
				SinOsc.ar(freq),
				pan
			) * EnvGen.ar(window, doneAction: Done.freeSelf)
		)
	}
).add;

SynthDef(\noiseGrain,
	{ arg out = 0, freq=800, sustain=0.001, amp=0.5, pan = 0;
		var window;
		window = Env.perc(0.002, sustain, amp * AmpCompA.kr(freq));
		Out.ar(out,
			Pan2.ar(
				Ringz.ar(PinkNoise.ar(0.1), freq, 2.6),
				pan
			) * EnvGen.ar(window, doneAction: Done.freeSelf)
		)
	}
).add;



Pdef(\sweep, { arg sustain=1, n=8, freq=440, ratio=0.1;
	Pbind(
		\instrument, \pgrain,
		\dur, sustain.value / n,
		\freq, Pseq((1..n)) * ratio + 1 * freq.value // freq is a function, has to be evaluated
	)
});
Pdef(\sweep2, { arg sustain=1, n=8, freq=440, ratio=0.1;
	Pbind(
		\instrument, \noiseGrain,
		\dur, sustain.value / n, // sustain is also a function, has to be evaluated
		\freq, Pseq((1..n).scramble) * ratio + 1 * freq.value,
		\recursionLevel, 2
	)
});
Pdef(\sweep3, { arg freq=440;
	Pbind(
		\type, \phrase,
		\instrument, \sweep,
		\freq, Pfunc({ rrand(0.8, 1.3) }) * freq.value,
		\dur, 0.3,
		\legato, 1.3,
		\n, 5
	)
});
)




// the pattern that is found in Pdef.all (or your own defined library) is truncated in time
// using the sustain provided by the outer pattern.
(
Pbind(
	\type, \phrase, // phrase event from global library
	\instrument, \sweep,
	\n, 15,
	\degree, Pseq([0, 4, 6, 3], inf),
	\sustain, Pseq([1.3, 0.2, 0.4],inf)
).play
)

// multichannel expansion is propagated into the subpatterns
(
Pbind(
	\type, \phrase, // phrase event from global library
	\instrument, \sweep,
	\n, 15,
	\degree, Pseq([0, 0, 6, 3], inf) + Prand([0, [0, 3], [0, 5], [0, 15]], inf),
	\ratio, Prand([ 0.1, 0.1, [0.1, -0.1] ], inf)
).play
)

// various instruments and synthdefs can be used on the same level
(
Pbind(
	\type, \phrase,
	\instrument, Pseq([\sweep, \default, \sweep2, \sweep3, \pgrain, \pgrain], inf),
	\degree, Pseq([0, 3, 2], inf),
	\dur, Pseq([1, 0.5], inf) * 0.7,
	\n, Pseq([4, 6, 25, 10], inf),
	\ratio, Prand([0.03, 0.1, 0.4, -0.1],inf) + Pseq([0, 0, [0, 0.02]], inf),
	\legato, Pseq(#[0.5, 1, 0.5, 0.1, 0.1],inf)
).play;
)


//////// of course also a patten can be used directly in a Pdef

(
Pdef(\sweep,
	Pbind(
		\instrument, Pseq([\pgrain, \noiseGrain],inf),
		\dur, Pseq([1, 2, 1, 3, 1, 4, 1, 5]) * 0.05,
		\legato, Prand([0.5, 0.5, 3],inf)
	)
)
)

// play directly, embedded in stream (see Pdef.help)

Pn(Pdef(\sweep), 2).play;
Pdef(\sweep).fork; // play without changing player state (see Pdef.help)


// play within a pattern
(
Pbind(
	\type, \phrase,
	\instrument, \sweep,
	\degree, Pseq([0, 1b, 4, 2, 3, 1b], inf),
	\pan, Pfunc(#{ 1.0.rand2 })
).play
)



//////// recursion examples //////////

// the given pattern can be recursively applied to itself
// resulting in selfsimilar sound structures, like lindenmeyer systems (see also Prewrite)
// special care is taken so that no infinite loops can happen.
// just like with non recursive phrasing, new values override old values,
// any values that are not provided within the pattern definition
// are passed in from the outer event.



(
Pdef(\sweep, { arg dur=1, n=4, freq=440, ratio=0.3;
	Pbind(
		\instrument, \pgrain,
		\dur, dur.value / n,	// now dur is dependant on outer dur.
		\freq, Pseries(1, 1, inf) * ratio + 1 * freq.value % 17000
	)
});
)


// no recursion
(
	Pbind(
		\type, \phrase,
		\instrument, \sweep,
		\degree, Pseq((0..5),inf)
	).play;
)

// no recursion, with legato > 1.0 and varying notes
// note how subpatterns are truncated to note length
// provided by outer pattern (in this case determined by legato)
(
	Pbind(
		\type, \phrase,
		\instrument, \sweep,
		\degree, Pseq((0..5),inf),
		\legato, Pseq([1.2, 2.8, 0.3], inf)
	).play;
)

// to block the proliferation of \legato into the phrase, set \transparency to 0
(
	Pbind(
		\type, \phrase,
		\instrument, \sweep,
		\transparency, 0,
		\degree, Pseq((0..5),inf),
		\legato, Pseq([1.2, 2.8, 0.3], inf)
	).play;
)


// recursion over one level
(
	Pbind(
		\type, \phrase,
		\instrument, \sweep,
		\degree, Pseq([0, 1, 2, 3], inf),
		\recursionLevel, 1
	).play
)

// recursion over one level: legato is recursively applied
(
	Pbind(
		\type, \phrase,
		\instrument, \sweep,
		\degree, Pseq([0, 1, 2, 3], inf),
		\legato, Pseq([0.5, 1, 1.5, 1.8], inf),
		\recursionLevel, 1
	).play
)

// to block the proliferation of properties such as \legato and \degree
// into the phrase, set \transparency to 0.
(
	Pbind(
		\type, \phrase,
		\instrument, \sweep,
		\degree, Pseq([0, 1, 2, 3], inf),
		\legato, Pseq([0.5, 1, 1.5, 1.8], inf),
		\recursionLevel, 1,
		\transparency, 0
	).play
)

// recursion over 3 levels: legato is recursively applied
(
	Pbind(
		\type, \phrase,
		\instrument, \sweep,
		\degree, 1,
		\legato, Pseq([0.5, 1, 1.3], inf),
		\recursionLevel, 3,
		\n, 3
	).play
)

// to block the proliferation of \legato into the phrase, set \transparency to a level at which
// to stop passing the value.
(
	Pbind(
		\type, \phrase,
		\instrument, \sweep,
		\degree, 1,
		\legato, Pseq([0.5, 1, 2.3], inf),
		\recursionLevel, 3,
		\n, 3,
		\transparency, Pstutter(8, Prand([0, 1, 2], inf))
	).play
)



// to modify this recursion, assign values explicitly:
(
Pdef(\sweep, { arg dur=1, n=4, ratio=0.5, freq=440;
	var legato;
	freq = freq.value;
	legato = freq % 200 / 200 * 3 + 0.2;
	Pbind(
		\instrument, \pgrain,
		\dur, dur.value / n,
		\legato, legato,
		\freq, Pseq((1..n) * ratio + 1 * freq)
	)
});
)

// recursion over one level: degree is assigned to each phrase,
// because freq is calculated internally and overrides degree on the second level
(
	Pbind(
		\type, \phrase,
		\instrument, \sweep,
		\degree, Pseq((0..10),inf),
		\recursionLevel, 1
	).play
)



// recursion over two levels
(
Pbind(
	\type, \phrase,
	\instrument, \sweep,
	\degree, 0,
	\recursionLevel, 2
).play
)

// recursion over three levels with variable number of grains
(
Pbind(
	\type, \phrase,
	\instrument, \sweep,
	\degree, -5,
	\n, Pseq([1, 2, 3],inf),
	\recursionLevel, 3
).play
)


// "zoom" in
TempoClock.default.tempo = 0.2;
TempoClock.default.tempo = 1.0;


// recursion over variable levels
(
Pbind(
	\type, \phrase,
	\instrument, \sweep,
	\n, Prand([2, 7, 3], inf),
	\degree, -5,
	\recursionLevel, Prand([0, 1, 2],inf)
).play
)



// replace the frequency based pattern with a degree based pattern
(
Pdef(\sweep, { arg sustain=1, n=8, degree=0, ratio=1;
	Pbind(
		\instrument, \pgrain,
		\dur, sustain.value / n,
		\degree, Pseq((1..n)) * ratio + 1 + degree.value
	)
});
)


// drunken master
(
Pbind(
	\type, \phrase,
	\instrument, \sweep,
	\n, Prand([2, 4, 3, 8], inf),
	\degree, Pseq([-5, 0, -2], inf),
	\legato, Pseq([1.4, 0.5, 2], inf),
	\scale, #[0, 2, 5, 7, 10],
	\recursionLevel, Prand([0, 1, 2],inf)
).play
)


(
Pbind(
	\type, \phrase,
	\instrument, \sweep,
	\synthDef, Prand([\pgrain, \default, \noiseGrain],inf),
	\n, Prand([2, 4, 3, 8], inf),
	\degree, Pseq([-5, 0, -2], inf),
	\recursionLevel, Prand([0, 1],inf)
).play
)


// use a different parent event in the inner pattern
(
e = Event.default;
e.use { ~sustain = { 2.0.exprand(0.05) } };
Pdef(\sweep, { arg sustain=1, n=8, degree=0, ratio=1;
	Pbind(
		\parent, e, // replace by some other event
		\instrument, \pgrain,
		\dur, sustain.value / n,
		\degree, Pseq((1..n)) * ratio + 1 + degree.value
	)
});
)


(
Pbind(
	\type, \phrase,
	\instrument, \sweep,
	\n, Prand([2, 4, 3, 8], inf),
	\degree, Pseq([-5, 0, -2], inf),
	\recursionLevel, Prand([0, 1],inf)
).play
)


// pass in a pattern from outside

(
Pdef(\sweep, { arg sustain=1, n=8, degree=0, ratio=1;
	n = n.value;
	Pbind(
		\instrument, \pgrain,
		\dur, sustain.value / n,
		\degree, Pseq([ 1, 2, 3, 4, 5 ] * ratio + 1 + degree.value) )
});
)


(
Pbind(
	\type, \phrase,
	\instrument, \sweep,
	\n, { Pshuf([2, 4, 3, 8, 16, 32], inf) }, // use a function to insulate from embedInStream
	\degree, Pseq([-5, 0, -2], inf),
	\recursionLevel, Prand([0, 1],inf)
).play
)




// recursion inside the pattern definition

(
Pdef(\sweep2, { arg sustain=1, n=2, degree=0, ratio=1;
	Pbind(
		\type, \phrase,
		\instrument, \sweep,
		\dur, sustain.value / n,
		\degree, Pseq((1..5).scramble * ratio + 1 + degree.value),
		\recursionLevel, 2
	)
});
)

(
Pbind(
	\type, \phrase,
	\instrument, \sweep2,
	\n, 3,
	\degree, Pseq([-5, 0, -2], inf)
).play
)


// instruments do not crossfade while they play (to make phrasing more efficient).


(
Pbind(
	\type, \phrase,
	\instrument, \sweep,
	\n, 3,
	\degree, Pseq([0, 2b, 3, 4], inf),
	\dur, 2,
	\legato, 2
).play
)

// change pattern definition while playing:
(
Pdef(\sweep,
	Pbind(
		\instrument, \pgrain,
		\dur, exprand(0.01, 0.1),
		\legato, rrand(0.01, 2.0),
		\octave, rrand(5, 7)
	)
)
)


// koch "snowflake"
(
Pdef(\koch, { arg dur=1, freq=440;
	Pbind(
		\dur, dur.value / 3,
		\freq, freq.value * Pseq([1, 1.2, 1])
	)
});
)

(
	Pbind(
		\type, \phrase,
		\instrument, \koch,
		\synthDef, \pgrain,
		\dur, 9,
		\recursionLevel, 2,
		\legato, 1.1
	).play
)

(
	Pbind(
		\type, \phrase,
		\instrument, \koch,
		\synthDef, \pgrain,
		\dur, 9,
		\recursionLevel, 4,
		\legato, 1.1
	).play
)

(
Pdef(\koch, { arg dur=1, degree=0;
	Pbind(
		\dur, dur.value / 3,
		\degree, degree + Pseq([0, 2, 0])
	)
});
)





// soundfile example


(
SynthDef(\play_from_to, { arg out, bufnum, from=0.0, to=1.0, sustain=1.0;
	var env;
	env = EnvGen.ar(Env.linen(0.01, sustain, 0.01), 1, doneAction: Done.freeSelf);
	Out.ar(out,
		BufRd.ar(1, bufnum,
			Line.ar(from, to, sustain) * BufFrames.kr(bufnum)
		) * env
	)


}).add;
)

b = Buffer.read(s, Platform.resourceDir +/+ "sounds/a11wlk01.wav")

(
Pdef(\poch, { arg sustain=1.0, from=0.0, to=1.0, n=3;
		var step;
		sustain = sustain.value;
		step = (to - from) / n;
		Pbind(
			\instrument, \play_from_to,
			\from, Pseries(from, step, n),
			\to, Pseries(from, step, n) + step,
			\legato, 1.0,
			\dur, sustain / n
		)
})
)

// this plays it straight
(
Pbind(
	\type, \phrase,
	\instrument, \poch,
	\recursionLevel, 3,
	\from, 0,
	\to, 1,
	\dur, 3,
	\bufnum, b
).play
)

// now turn round every middle part of every middle part
(
Pdef(\poch, { arg sustain=1.0, from=0.0, to=1.0, n=3;
	var step, f, t, i;
	sustain = sustain.value;
	step = (to - from) / n;
	f = Array.series(n, from, step) +.t [0.0, step];
	i = n div: 2;
	f[i] = f[i].reverse;
	Pbind(
		\instrument, \play_from_to,
		[\from, \to], Pseq(f),
		\legato, 1.0,
		\dur, sustain / n
	)
})
)


// varying recursion
(
Pbind(
	\type, \phrase,
	\instrument, \poch,
	\recursionLevel, Prand([0, 1, 2, 3], inf),
	\from, 0,
	\to, Prand([-1, 1], inf),
	\dur, 3,
	\n, Prand([1, 2, 3], inf),
	\bufnum, b,
	\amp, 0.2
).play
)
::
]