// 17.0 keyPressed 1QAZ FFT

​

// Keyboard cords:

// A-G-K --> "C Major cord"

// D-J-; --> "D cord"

// G-L-Enter --> "E Major cord"

​

let a_keys = {};

let a_waves = {};

let fade_in = 0.1;

let fade_out = 0.5;

let a_volume = 0.1;

let a_fft;

let a_start = 0;  // Window onto fft data

let a_end = 100;

​

function setup() {

  createCanvas(640, 300);

  a_fft = new p5.FFT();

  sketch_ui();

}

​

function draw() {

  background(200);

  show_value('a_keys', a_keys)

  show_fft();

}

​

function show_fft() {

  // plot FFT.analyze() frequency analysis on the canvas

  let spectrum = a_fft.analyze();

  // spectrum.length = 1024

​

  let i_start = Math.round(spectrum.length * a_start / 1000)

  let i_end = Math.round(spectrum.length * a_end / 1000)

  let b_len = width / (i_end - i_start);

  // print('i_start', i_start, 'i_end', i_end, 'blen', blen);

  for (let i = i_start; i < i_end; i++) {

    fill(spectrum[i], 0, 0);

    let x = map(i, i_start, i_end, 0, width);

    let h = map(spectrum[i], 0, 255, 0, height);

    rect(x, height-h, b_len, h);

  }

}

​

// Create a new oscillator on each keypress

function keyPressed() {

  let midi = a_notes[key];

  if (midi !== undefined) {

    let freq = midiToFreq(midi);

    a_keys[key] = round(freq) || -1;

    let wave = a_waves[key];

    if (!wave) {

      wave = new p5.Oscillator('sine');

      wave.freq(freq);

      wave.start();

      wave.amp(0);

      wave.amp(a_volume, fade_in);

      a_waves[key] = wave;

    }

  }

  // prevent any default behavior

  return false;

}

​

function keyReleased() {

  // print('keyReleased', key);

  delete a_keys[key];

  let wave = a_waves[key];

  if (wave) {

    wave.amp(0, fade_out);

    delete a_waves[key];

  }

  // prevent any default behavior

  return false;

}

​

// https://editor.p5js.org/jht1493/sketches/S47diDJcd

// keyPressed 1QAZ FFT

​

// https://en.wikipedia.org/wiki/Piano_key_frequencies

​

// https://editor.p5js.org/icm4.0/sketches/NArBLGfRM

// Random Diatonic Chords 2:4 Chords

​

// https://editor.p5js.org/p5/sketches/Sound:_Note_Envelope

​

​