​

function setup() {

  createCanvas(600, 400);

}

​

function draw() {

  background(0);

  for (let i = 0; i < 3; i++) {

    // let p = new Particle();

    particles.push(new Particle());

  }

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

    particles[i].update();

    particles[i].show();

    if (particles[i].finished()) {

      // remove this particle

      particles.splice(i, 1);

    }

  }

​

}

​

class Particle {

​

  constructor() {

    this.x = width/2;

    this.y = height/2;

    this.vx = random(-5, 5);

    this.vy = random(-5, 5);

    this.alpha = 255;

  }

​

  finished() {

    return this.alpha < 0;

  }

​

  update() {

    this.x += this.vx;

    this.y += this.vy;

    this.alpha -= 4;

  }

​

  show() {

    noStroke();

    fill(255, this.alpha);

    ellipse(this.x, this.y, 10);

  }

​

}