​

function setup() {

  createCanvas(windowWidth, windowHeight);

}

​

function draw() {

  background(0);

  particles.push(new Particle());

  for (let i = particles.length - 1; i >= 0; i--) {

    particles[i].show();

    particles[i].update();

    if (particles[i].alpha < 0) {

      particles.splice(i, 1);

    }

  }

}

​

class Particle {

  constructor() {

    this.x = width / 2;

    this.y = height;

    this.r = random(200, 255);

    this.g = random(100, 255);

    this.b = random(0, 100);

    this.alpha = 230;

    this.size = random(25, 40);

    this.changeX = random(-1, 1);

    this.changeY = random(-5, -1);

  }

​

  show() {

    noStroke();

    fill(this.r, this.g, this.b, this.alpha);

    ellipse(this.x, this.y, this.size);

  }

​

  update() {

    this.x += this.changeX;

    this.y += this.changeY;

    this.alpha -= 1;

  }

}