* @name Frequency Spectrum

 * @description <p>Visualize the frequency spectrum of live audio input.</p>

 * <p><em><span class="small"> To run this example locally, you will need the

 * <a href="http://p5js.org/reference/#/libraries/p5.sound">p5.sound library</a>

 * and a running <a href="https://github.com/processing/p5.js/wiki/Local-server">local server</a>.</span></em></p>

 */

let mic, fft, banana;

​

function setup() {

  createCanvas(710, 400);

  noFill();

  banana = new p5.Filter();

  banana.setType('bandpass');

  banana.freq(300);

  banana.res(0.1);

  banana.disconnect();

  mic = new p5.AudioIn();

  mic.connect(banana);

  mic.start();

  fft = new p5.FFT();

  fft.setInput(banana);

}

​

function draw() {

  background(200);

​

  let spectrum = fft.analyze(128);

​

//  beginShape();

  let offset = 8;

  for (i = offset; i < (spectrum.length / 8) + offset; i++) {

//    circle(40*(i-offset), 200, spectrum[i]);

      let origin = 40 * (i-offset);

      triangle(origin, 200, origin + 38, 200, origin, 200 - spectrum[i]);

//    vertex(i, map(spectrum[i], 0, 255, height, 0));

  }

//  endShape();

}

​