var particles = [];

​

function setup() {

  createCanvas(windowWidth,windowHeight);

  noStroke();

}

​

function draw() {

​

  background(0);

  if(frameCount%2==0){

    particles.push(new Particle(random(10,45),random(30,45)));

    particles.push(new Particle(random(195, 220), random(195, 220)));

  }

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

    var p = particles[i];  

    p.update();

    p.display();

    if(p.isOutside() || p.a <= -10){

      particles.splice(i,1);

    }

  }

  //console.log(particles.length);

}

​

class Particle{

  constructor(vx,vy){

    this.vx = vx;

    this.vy = vy;

    this.num = 255;

    this.a = 255;

    this.loc = createVector(width/2,height/2);

    this.vel = createVector(0,0);  

    this.acc = createVector(1,1);

  }

​

  update(){

    this.vel.add(this.acc);

    this.loc.add(this.vel);

    this.acc.mult(0);

    this.vel.limit(0.05);

  }

​

  isOutside(){

    if(this.loc.x < 0 ||this.loc.y>width || this.loc.y < 0 || this.loc.y >height){

      return true;

    }

    return false;

  }

  display(){

    this.acc = createVector(sin(radians(this.vx+this.num/2))/2,cos(radians(this.vy-this.num/2))/2);

​

​

    fill(255,this.a);

    var r = map(this.a,255,0,1,10);

    ellipse(this.loc.x,this.loc.y,r);

    this.num += map(this.a,255,0,1,0);

    this.a -= 0.1;

  }

}