Oscilloscope

var sound;
var slider1;
var toggle;
var center1;
var center2;
var soundColor;
var d;

function setup() {
  createCanvas(500, 500);
  smooth();

  slider1 = createSlider(.5, 15, 7);
  slider1.position(200, 15);

  var button1 = createButton('wave style');
  button1.mousePressed(toggle);
  button1.position(19, 19);

  sound = new p5.AudioIn();
  sound.start();
  fft = new p5.FFT(1.0, 256);
  fft.setInput(sound);

}

function draw() {
  background(30, 0, 40);

  var slideVal1 = slider1.value();
  sound.amp(slideVal1);
  
  waveformer(20, 120, 255);
  waveformer(80, 255, 80);
  waveformer(255, 40, 255);

}

function toggle() {
  if (center1 === undefined) {
    center1 = 250;
    center2 = 250;
  } else {
    center1 = undefined;
    center2 = undefined;
  }
}

function waveformer(r, b, g) {
  var waveform = fft.waveform();

  noFill();
  beginShape();
  stroke(r, b, g);
  strokeWeight(1);

  for (var i = 0; i < waveform.length; i++) {
    var x = map(i, 0, waveform.length, 0, width);
    var y = map(waveform[i], -1, 1, 0, height);
    vertex(x, y);
    vertex(x + 2, y + 2);
    vertex(center1, center2);
  }
  endShape();
}