var playing = false;

​

function setup() {

  createCanvas(windowWidth,windowHeight);

  backgroundColor = color(255,0,255);

  textAlign(CENTER);

}

​

function draw() {

  background(255);

  if(playing) text("playing",width/2,height/2);

}

​

function touchStarted() {

  osc = new p5.Oscillator();

  osc.setType('sine');

  osc.freq(240);

  osc.amp(0.1);

  osc.start();

  playing = true;

  return false;

}

​

function touchEnded() {

  if(touches.length == 0) {

    playing = false;

    osc.stop();

  }

}