let w; // Width of entire wave

let theta = 0.0; // Start angle at 0

let amplitude = 75.0; // Height of wave

let period = 500.0; // How many pixels before the wave repeats

let dx; // Value for incrementing x

let yvalues; // Using an array to store height values for the wave

let offset = 25;

​

function setup() {

  createCanvas(710, 400);

  w = width + 16;

  dx = (TWO_PI / period) * xspacing;

  yvalues = new Array(floor(w / xspacing));

}

​

function draw() {

  background(0);

  calcWave();

  renderWave();

}

​

function calcWave() {

  // Increment theta (try different values for

  // 'angular velocity' here)

  theta += 0.04;

​

  // For every x value, calculate a y value with sine function

  let x = theta;

  console.log(yvalues.length)

  for (let i = 0; i < yvalues.length; i++) {

    yvalues[i] = sin(x) * amplitude;

    x += dx;

  }

}

​

function renderWave() {

  // A simple way to draw the wave with an ellipse at each location

  stroke(237, 34, 93);

  fill(255, 0,0,100)

  beginShape();

  for (let x = 0; x < yvalues.length; x++) {

    vertex(x * xspacing + offset, height / 2 + yvalues[x] + offset);

  }

  for (let x = yvalues.length; x > 0; x--) {

    vertex(x * xspacing - offset + offset, height / 2 + yvalues[x] - offset);

  }

  endShape();

}