push aliens into array - OpenProcessing

mySketch
xxxxxxxxxx
 
var w = 64;
var h = 64;
var dx = 0;
var topAlien = []; 
var fr = 0;
var speed = 2;
​
function preload(){
  aliens = loadImage("Spaceinvaders1.png");
}
function setup() {
  createCanvas(windowWidth, windowHeight);
  for (var i = 0; i < 10; i++) {
    topAlien.push(new Alien1(i*80));
  }
  for (var i = 0; i < 10; i++){
    topAlien.push(new Alien2(i*80));
  }
  frameRate(2);
  //print(topAlien);
}
​
function draw() {
  background(0);
  update();
  for (var i=0; i< topAlien.length; i++) {
    topAlien[i].display();
  }
  for (var i=0; i< topAlien.length; i++) {
    topAlien[i].display();
  }
}
​
function update(){
  fr = fr + 1;
  if (fr >= 2){
    fr = 0;
  }
}
function Alien1(dx){
  this.dx = dx;
  this.display = function(){
    dx = dx + speed;
    if (fr == 0){
      copy(aliens, 242, 104, 65, h, dx, 100, w, h);
    }  
  }
}
​
function Alien2(dx){
  this.dx = dx;
  this.display = function(){
    dx = dx + speed;
    if (fr == 1){
    copy(aliens, 338, 104, 65, h, dx, 100, w, h);  
    }
  }
}