// http://codingtra.in

// http://patreon.com/codingtrain

// Code for: https://youtu.be/17WoOqgXsRM

​

function Star() {

  this.x = random(-width, width);

  this.y = random(-height, height);

  this.z = random(width);

  this.pz = this.z;

​

  this.update = function() {

    this.z = this.z - speed;

    if (this.z < 1) {

      this.z = width;

      this.x = random(-width, width);

      this.y = random(-height, height);

      this.pz = this.z;

    }

  }

​

  this.show = function() {

    fill(255);

    noStroke();

​

    var sx = map(this.x / this.z, 0, 1, 0, width);

    var sy = map(this.y / this.z, 0, 1, 0, height);

​

    var r = map(this.z, 0, width, 16, 0);

    ellipse(sx, sy, r, r);

​

    var px = map(this.x / this.pz, 0, 1, 0, width);

    var py = map(this.y / this.pz, 0, 1, 0, height);

​

    this.pz = this.z;

​

    stroke(255);

    line(px, py, sx, sy);

​

  }

}