song

var song; 

var inc = 0.02;

var start = 0;

var col; 

​

function preload(){

  song = loadSound("wave.wav");

}

​

function setup() {

  createCanvas(windowWidth, windowHeight);

  strokeWeight(10);

  song.setVolume(.1);

  song.loop();

  song.play();

}

​

function draw() {

  background(120);

  var col = color(100, 40, 0);

  background(song.currentTime()*20, 90, 255);

    noFill();

    beginShape();

    stroke(col);

    var xoff = start;

    for (var x = 0; x < width; x++){

      var y = height/2 + sin(xoff)*height/5;

      vertex(x, y);

      xoff += inc;

    }

    start += inc;

    endShape();

}