var smokes;

var d;

var gravity;

​

function setup() {

  //createCanvas(450,450);

  createCanvas(windowWidth,windowHeight);

  frameRate(60);

  reset();

  background(0);

}

​

function draw() {

  blendMode(BLEND);

  background(0,2);

  blendMode(ADD);

    fill(255,127);

    noStroke();

  for(var i=0;i<n;i++){

    smokes[i].move();

    smokes[i].draw();

  }

}

​

function reset(){

  n = 2000;

  smokes = [];

  d = 2;

  gravity = 0;

  for(var i=0;i<n;i++){

    var rx = 0;

    var ry = 0;

    //var rx = random(width/6);

    //var ry = random(height/6);

    smokes[i] = new Smokep(rx,ry);

  }

}

​

function touchStarted(){

  reset();

}

​

class Smokep{

  constructor(rx, ry){

    this.x = random(width/2-rx,width/2+rx);

    this.y = random(height/2-ry,height/2+ry);

    this.angle = random(TWO_PI);

    this.ax = random(0.5*cos(this.angle));

    this.ay = random(0.5*sin(this.angle));

    this.vx = 0;

    this.vy = 0;

  }

  move(){

    this.vx += this.ax;

    this.vy += this.ay;

    this.ax *= 0.8;

    this.ay *= 0.8;

    this.y += gravity;

    this.x += this.vx;

    this.y += this.vy;

    //this.bounce();

    this.moveCenter();

  }

  moveCenter(){

    if(0.01>random(1)){

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

      this.x=width/2;

      this.y=height/2;

      this.vx *= 0.5;

      this.vy *= 0.5;

    }

  }

  }

  bounce(){

    if(this.x<=0){

      this.x=0;this.vx=-this.vx;this.ax=-this.ax;

    }else if(this.x>=width){

      this.x=width;this.vx=-this.vx;this.ax=-this.ax;

    }

    if(this.y<=0){

      this.y=0;this.vy=-this.vy;this.ay=-this.ay;

    }else if(this.y>=height){

      this.y=height;this.vy=-this.vy;this.ay=-this.ay;

    }

  }

  draw(){

    circle(this.x,this.y,d);

  }

}