*  Draw a buffer of audio samples. Use the p5.FFT

 *  (Web Audio API Analyzer Node) as a fast way to

 *  get the time domain data, pre-fft.

 * 

 *  Press T to toggle input between soundFile, mic, and oscillator.

 *  Oscillator's frequency is mapped to mouse position.

 *

 *  This example includes drag & drop with p5.dom.

 */

​

var mic, osc;

​

var analyzer;

var numSamples = 1024;

​

// Array of amplitude values (-1 to +1) over time.

var samples = [];

var currentSource = "mic";

​

function setup() {

  var cnv = createCanvas(windowWidth, windowHeight);

  noFill();

  stroke(240);

  textFont('monospace');

​

  analyzer = new p5.FFT(0, numSamples);

​

  // set up various inputs. We'll toggle them when key "T" is pressed.

  mic = new p5.AudioIn();

  osc = new p5.Oscillator();

  osc.amp(0.5);

  osc.freq(10);

​

  mic.start();

  analyzer.setInput(mic);

​

}

​

function draw() {

  background(255, 200);

​

  // get a buffer of 1024 samples over time.

  samples = analyzer.waveform();

  var bufLen = samples.length;

​

  // draw snapshot of the samples

  strokeWeight(4);

  stroke(66, 244, 155);

  noFill();

  beginShape();

  for (var i = 0; i < bufLen; i++){

    var x = map(i, 0, bufLen, 0, width);

    var y = map(samples[i], -1, 1, -height/2, height/2);

    vertex(x, y + height/2);

  }

  endShape();

​

  // map the oscillator frequency to mouse position

  var freq = map(mouseX, 0, windowWidth, 1, 440);

  osc.freq(freq, 0.01);

  var amp = map(mouseY, height, 0, 0, 1);

  osc.amp(amp, 0.01);

​

  labelStuff(freq, amp);

}

​

​

// draw text

function labelStuff(freq, amp) {

    fill(0);

  noStroke();

  text('Press T to toggle source', 20, 20);

  text('Source: '+ currentSource, 20, 40);

​

  // if currentSource is an oscillator:

  if (currentSource === 'sine' || currentSource == 'triangle' || currentSource == 'square' || currentSource == 'sawtooth') {

    text('Frequency: ' + freq, 20, 60);

    text('Amplitude: ' + amp, 20, 80);

  }

}

​

​

// ============

// toggle input

// ============

​

function keyPressed() {

  if (key == 'T') {

    toggleInput();

  }

}

​

​

// start with mic as input

var inputMode = 0;

​

function toggleInput(mode) {

  if (typeof(mode) === 'number') {

    inputMode = mode;

  } else {

    inputMode += 1;

    inputMode = inputMode % 5;

  }

  switch (inputMode) {

    case 0: // mic mode

            osc.stop();

      mic.start();

      analyzer.setInput(mic);

      currentSource = 'mic';

      break;

    case 1: // sine mode

      osc.setType('sine');

      osc.start();

      mic.stop();

      analyzer.setInput(osc);

      currentSource = 'sine';

      break;

    case 2: // square mode

      osc.setType('triangle');

      currentSource = 'triangle';

      break;

    case 3: // square mode

      osc.setType('square');

      currentSource = 'square';

      break;

    case 4: // square mode

      osc.setType('sawtooth');

      currentSource = 'sawtooth';

      break;

  }

}

​