let p = 0;

let t = 0;

​

function setup(){

  createCanvas(windowWidth, windowHeight);

}

​

function draw() {

  p=sin(v)*255;

  t = abs(p);

  background(t);

}

function touchMoved() {

  v = v + 0.01;

  }

​

function mouseWheel() {  

    v = v + 0.01;

}

​

/*function mouseWheel() { 

    if (event.deltaY > 0) {

    v = v + 0.01;

  }

  else {

    v = v - 0.01;

  }

}*/