var index = [];

var indexed_sequence = [];

​

var markov = []; //this will be an array of arrays

var index_size;

var pitches = [];

​

var keys;

var toneLoop;

var currentPitch;

var score;

​

function preload() {

  score = loadJSON("data/bach.json", loaded, error);

}

​

function setup() {

  sequence = [];

  //load first track into sequence

  for(var i = 0; i < score.tracks[1].notes.length; i++){

    var note = score.tracks[1].notes[i];

    sequence.push(note.midi);

  }

  print(sequence);

  keys = new Tone.PolySynth(3, Tone.Synth);

  keys.toMaster();

  index_size = 0;

  //process sequence

  // var new_item = true;

  //step 1: analyze sequence

  for(var i =0; i < sequence.length; i++){

    new_item = true;

    //check if item is new. if not, point to existing index

    for(var j = 0; j < index_size; j++){

      if(sequence[i] == index[j]){

        new_item = false;

        indexed_sequence[i] = j;

      }

    }

    if(new_item){

      index[index_size] = sequence[i];

      indexed_sequence[i] = index_size;

      index_size++;

    }

  }

  print("raw sequence: "+ sequence);

  print("index: " + index);

  print("indexed sequence: " + indexed_sequence);

  //step 2: create transition matrix

  //create table

  for(var i = 0; i < index_size; i++){

    markov[i] = [];

  }

  for(var i = 0; i < indexed_sequence.length; i++){ //for each unique pitch

    var current = indexed_sequence[i];

    var next_pos = (i + 1) % indexed_sequence.length;

    var next = indexed_sequence[next_pos];

    markov[current].push(next);

  }

  //print transition table

  for(var i = 0; i < markov.length; i++){

    print(markov[i]);

  }

  //step 3: create melody

  var melodyLength = 100;

  var currentIndex = parseInt(random(0, markov.length)); //start anywhere

  for(var i = 0; i < melodyLength; i++){

    var transitionPos = parseInt(random(0, markov[currentIndex].length));

    var nextIndex = markov[currentIndex][transitionPos];

    currentIndex = nextIndex;

    pitches.push(index[currentIndex]);

  }

  print("generated melody: " + pitches);

  currentPitch = 0;

  //play back melody

  //triggered every eighth note. 

  toneLoop =  new Tone.Loop(function(time){

    var pitch = Tone.Frequency( pitches[currentPitch], "midi");

    keys.triggerAttackRelease(pitch, "16n");

    currentPitch = (currentPitch + 1) % pitches.length;

  }, "8n").start(0);

  Tone.Transport.start();

}

​

function draw() {

}

​

function loaded(d) {

  score = d;

}

​

function error(err){

  print(err);

}

​

​

​