let sloop;

​

let validNotes = [...Array(128).keys()];

let validTokens = validNotes.concat([-1]);

let minValidNote, maxValidNote;

let songLength = 32; // 4 bars * 8th-note resolution

​

let maxPopulationSize = 70;

let numberOfSurvivors = 20;

let population = [];

let generationCount = 1;

​

let songIsPlaying = false;

let clickedEarwormIndex;

let notePlaybackIndex;

// Fitness rules

let desiredKeyClasses = [0, 2, 4, 5, 7, 9, 11];

let minGoodPitch = 60;

let maxGoodPitch = 84;

​

function setup() {

  createCanvas(800, 500);

  colorMode(HSB, 255);

  frameRate(10);

​

  sloop = new p5.SoundLoop(soundLoop, 0.3); // Loop plays every 0.3s

  synth = new p5.PolySynth();

​

  minValidNote = min(validNotes);

  maxValidNote = max(validNotes);

  for (let i = 0; i < maxPopulationSize; i++) {

    let song = new Earworm(i);

    song.initialize();

    population.push(song);

  }

​

  //selectionButton = createButton("Best 10");

  //selectionButton.mouseClicked(selectFittest);

  //selectionButton.position(10, 10);

  reproductionButton = createButton("Reproduce");

  reproductionButton.mouseClicked(reproducePopulation);

  reproductionButton.position(10, 40);

  fastForwardButton = createButton("10 Generations lAter");

  fastForwardButton.mouseClicked(fastForward);

  fastForwardButton.position(10, 70);

  resetButton = createButton("Reset");

  resetButton.mouseClicked(resetPopulation);

  resetButton.position(10, 100);

}

​

function soundLoop(cycleStartTime) {

  let duration = this.interval;

  let velocity = 0.7;

  let midiNote = population[clickedEarwormIndex].notes[notePlaybackIndex];

  let noteFreq = midiToFreq(midiNote);

  synth.play(noteFreq, velocity, cycleStartTime, duration);

  // Move forward the index, and stop if we've reached the end

  notePlaybackIndex++;

  if (notePlaybackIndex >= population[clickedEarwormIndex].notes.length) {

    this.stop(cycleStartTime);

    songIsPlaying = false;

  }

}

​

function draw() {

  background(0, 0, 255, 150);

  for (let i = 0; i < population.length; i++) {

    population[i].display();

  }

  fill(255);

}

function mousePressed() {

  if (songIsPlaying) {

    // Stop a song

    sloop.stop();

    songIsPlaying = false;

  } else {

    // Start a song

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

      var clickToEarwormDistance = dist(mouseX, mouseY, population[i].xpos, population[i].ypos);

      if (clickToEarwormDistance < population[i].radius) {

        clickedEarwormIndex = i;

        notePlaybackIndex = 0;

        songIsPlaying = true;

        console.log(population[clickedEarwormIndex].notes);

        sloop.start();

      }

    }

  }

}

​

function selectFittest() {

  // Sort in descending order of fitness

  population.sort((a, b) => b.fitnessScore - a.fitnessScore);

  // Keep only the N fittest

  population = subset(population, 0, numberOfSurvivors);

  // Re-assign ID numbers

  for (let i = 0; i < population.length; i++) {

    population[i].id = i;

  }

}

​

function reproducePopulation() {

  let newPopulation = [];

  while (newPopulation.length < maxPopulationSize - numberOfSurvivors) {

    let parentA = random(population);

    let parentB = random(population);

    let child = parentA.reproduceWith(parentB);

    newPopulation.push(child);

  }

  // Add new generation to the survivors

  population = population.concat(newPopulation);

  // Re-assign ID numbers

  for (let i = 0; i < population.length; i++) {

    population[i].id = i;

  }

  generationCount++;

}

​

function fastForward() {

  let fastForwardNum = 10;

  for (let i = 0; i < fastForwardNum; i++) {

    selectFittest();

    reproducePopulation();

  }

}

​

function resetPopulation() {

  generationCount = 1;

  for (let i = 0; i < maxPopulationSize; i++) {

    let song = new Earworm(i);

    song.initialize();

    population[i] = song;

  }

}

​

function Earworm(indexNumber) {

  this.id = indexNumber;

  this.length = songLength;

  this.notes = [];

  this.fitnessScore = 0;

  // Visual properties

  this.xpos = random(width);

  this.ypos = random(height);

  this.radius = (width + height) / 50;

}

Earworm.prototype.initialize = function() {

  this.notes = [];

  for (let i = 0; i < this.length; i++) {

    let token = random(validTokens);

    if (random(1) > 0.2) {

      this.notes.push(random(validNotes));

    } else {

      this.notes.push(-1);

    }

  }

  this.calculateFitness();

};

Earworm.prototype.calculateFitness = function() {

  this.fitnessScore = 0;

  // Key

  for (let i = 0; i < this.notes.length; i++) {

    let keyClass = this.notes[i] % 12;

    if (desiredKeyClasses.indexOf(keyClass) >= 0) {

      this.fitnessScore = this.fitnessScore + 10;

    }

  }

  // Prefer smaller intervals

  for (let i = 0; i < this.notes.length - 1; i++) {

    let currentNote = this.notes[i];

    let nextNote = this.notes[i + 1];

    let interval = abs(nextNote - currentNote);

    this.fitnessScore = this.fitnessScore - interval;

​

    // Consonant / dissonant intervals

    // https://www.howmusicreallyworks.com/Pages_Chapter_4/4_2.html#4.2.6

    let consonantIntervals = [3, 4, 5, 7, 8, 9];

    let dissonantIntervals = [1, 2, 6, 10, 11];

    if (consonantIntervals.indexOf(interval)) {

      this.fitnessScore = this.fitnessScore + 10;

    } else if (dissonantIntervals.indexOf(interval)) {

      this.fitnessScore = this.fitnessScore - 10;

    }

  }

  // Pitch range

  for (let i = 0; i < this.notes.length; i++) {

    if (this.notes[i] > minGoodPitch) {

      this.fitnessScore = this.fitnessScore + 5;

    }

    if (this.notes[i] < maxGoodPitch) {

      this.fitnessScore = this.fitnessScore + 5;

    }

  }

  // Good ratio of empty and non-empty notes

  let empty = 0;

  let targetEmptyRatio = 0.5;

  for (let i = 0; i < this.notes.length; i++) {

    if (this.notes[i] === -1) {

      empty++;

    }

  }

  let emptyRatio = empty / (this.notes.length - empty);

  this.fitnessScore = this.fitnessScore - (targetEmptyRatio - emptyRatio) * 100;

};

Earworm.prototype.reproduceWith = function(partner) {

  let partitionIndex = round(random(this.notes.length));

  let partA = subset(this.notes, 0, partitionIndex);

  let partB = subset(partner.notes, partitionIndex, partner.notes.length);

  let child = new Earworm(0);

  child.notes = partA.concat(partB);

  child.mutate(); // Add some random variation

  child.calculateFitness();

  return child;

};

Earworm.prototype.mutate = function() {

  for (let i = 0; i < this.notes.length; i++) {

    if (random(100) > 80) {

      // this.notes[i] = random(validTokens);

      if (random(1) > 0.2) {

        this.notes[i] = random(validNotes);

      } else {

        this.notes[i] = -1;

      }

    }

  }

};

Earworm.prototype.display = function() {

  this.xpos = constrain(this.xpos + random(-1, 1), 0, width);

  this.ypos = constrain(this.ypos + random(-1, 1), 0, height);

​

  push();

  strokeWeight(0.5);

  angleMode(DEGREES); // Change the mode to DEGREES

  let angle = 360 / this.notes.length;

  translate(this.xpos, this.ypos);

  for (let i = 0; i < this.notes.length; i++) {

    rotate(angle);

    if (this.notes[i] === -1) {

      continue;

    }

    let pitchClass = this.notes[i] % 12;

    let color = map(pitchClass, 0, 12, 280, 120) % 255;

    let length = map(this.notes[i], minValidNote, maxValidNote, this.radius / 2, this.radius);

    strokeWeight(0.5);

    stroke(color, 180, 250);

    if (songIsPlaying) {

      if (this.id == clickedEarwormIndex) {

        stroke(color, 180, 250);

        if (i == notePlaybackIndex) {

          strokeWeight(2);

          length = this.radius;

        } else {

          strokeWeight(1);

        }

      } else {

        stroke(color, 255, 100);

      }

    }

    line(0, 0, length, 0);

  }

  pop();

};