SuperCollider L-System Sequencer

Parallel playing sequencer for SuperCollider based on Lindenmayer system

Installation

1. L-System string generator

   First of all you need to generate L-System string somewhere. There is a NatureToolkit quark for SuperCollider which can do that

2. Classes installation

   Run Platform.userExtensionDir in SuperCollider (MacOS) to see classes extensions directory. After that just clone that repo into that folder

Usage

Generate L-System string

var lsysTree = LSys("F1F1F1", [
  "0<0>0" -> "1",
  "0<0>1" -> "1[-F1F1]",
  "0<1>0" -> "1",
  "0<1>1" -> "1",
  "1<0>0" -> "0",
  "1<0>1" -> "1F1",
  "1<1>0" -> "1",
  "1<1>1" -> "0",
  "+" -> "-",
  "-" -> "+"
], "+-F[]");

~lsysTreeString = lsysTree.applyRules(22);

Create SynthDef

SynthDef.new(\lpad, {
  arg buf=0, freq=1000, detune=0.2,
  amp=0.3, pan = 0.0, out = 0, rout = 0, rsend = (-20),
  atk = 0.1, dec = 0.1, sus = 1.0, rel = 1, curve = -4, gate = 1;
  var sig, env, detuneCtrl;
  env = EnvGen.ar(Env.adsr(atk, dec, sus, rel, curve: curve), gate,
    doneAction: 2
  );

  detuneCtrl = LFNoise1.kr(0.2!50).bipolar(detune).midiratio;
  sig = Osc.ar(buf, freq * detuneCtrl, {Rand(0,2pi)}!10);

  sig = Splay.ar(sig);
  sig = LeakDC.ar(sig);
  sig = Pan2.ar(sig, pan, amp);
  Out.ar(out, sig * env);
}).add;

Create replacement functions

~baseFreq = 130.81;
~upperFreq = ~baseFreq * 1.12;
~lowerFreq = ~baseFreq / 1.5;

~funcF = {
  arg nodeItem, index, list;
  var dict = Dictionary[\freq -> ~baseFreq];
  if (list.at(0).isCollection, {
    switch(list.at(0).at(\id).asString,
      "UP", {
        dict.putPairs([
          \freq, (~upperFreq + 34)
        ]);
      },
      "DOWN", {
        dict.putPairs([
          \freq, (~lowerFreq - 15)
        ]);
      }, {
        dict.putPairs([
          \freq, (~baseFreq)
        ]);
      }
    );
  });
  dict;
};

~func1 = {
  arg nodeItem, index, list;
  var dict = Dictionary[\freq -> (~baseFreq + 34)];
  switch(list.at(0).at(\id).asString,
    "UP", {
      dict.putPairs([
        \freq, (~upperFreq + 34)
      ]);
    },
    "DOWN", {
      dict.putPairs([
        \freq, (~lowerFreq - 25)
      ]);
    }, {
      dict.putPairs([
        \freq, (~baseFreq + 34)
      ]);
    }
  );
  dict;
};

~func0 = {
  arg nodeItem, index, list;
  var dict = Dictionary[\freq -> (~baseFreq + 68)];
  switch(list.at(0).at(\id).asString,
    "UP", {
      dict.putPairs([
        \freq, (~upperFreq + 68)
      ]);
    },
    "DOWN", {
      dict.putPairs([
        \freq, (~lowerFreq - 35)
      ]);
    }, {
      dict.putPairs([
        \freq, (~baseFreq + 68)
      ]);
    }
  );
  dict;
};

~funcPlus = {
  arg nodeItem, index, list;
  var dict = Dictionary.new;
  dict.putPairs([
    \freq, ~upperFreq,
    \id, "UP"
  ]);
  dict;
};

~funcMinus = {
  arg nodeItem, index, list;
  var dict = Dictionary.new;
  dict.putPairs([
    \freq, ~lowerFreq,
    \id, "DOWN"
  ]);
  dict;
};

Create L-System sequencer with specified offset between each pattern

~pads = LSequencer.new(
  lsysString: ~lsysTreeString,
  transformRules: [
    "F" -> ~funcF,
    "1" -> ~func1,
    "0" -> ~func0,
    "-" -> ~funcMinus,
    "+" -> ~funcPlus
  ],
  pbindKeys: Dictionary.newFrom([
    \instrument, \lpad,
    \dur, Pdefn(\dur, Prand([5.0, 6.0], inf)),
    \atk, Pdefn(\atk, 8),
    \dec, Pdefn(\dec, 0.1),
    \sus, Pdefn(\sus, 0.1),
    \rel, Pdefn(\rel, 4),
    \curve, Pdefn(\curve, 0.5),
    \detune, Pdefn(\detune, Pwhite(0.01, 0.8, inf)),
    \amp, Pdefn(\amp, 0.2),
    \out, 0,
    \buf, Pdefn(\buf, Pwhite([1.0, 9.0], inf))
  ]),
  offset: 1

Enjoy

~pads.play