let interval = 60;

​

// Position

let x = 0;

let y = 0;

let z = 0;

​

let video;

let a = 0;

​

function setup() {

  createCanvas(windowWidth, windowWidth*480/640);

  video = createCapture(VIDEO);

  video.hide();

  noStroke();

  //imageMode(CENTER);

}

​

function draw() {

  //background('white');

  push();

  translate(width, 0);

  scale(-1, 1);

  image(video, 0, 0, width, (width*480)/640);

  pop();

  // Every second, pick a new random position

  if (frameCount % interval == 0) {

    x = random(width);

    y = random(height);

    z = random(100);

    interval = floor(random(300, 1500));

    background(255);

  }

  a++;

  // Fill a red spot

  stroke(255, 0, 0, a);

  strokeWeight(50);

  // Draw the spot

  point(x, y);

}