Emanuele Feronato

var game;
var ship;
var barrierGroup;
var shipHorizontalSpeed = 400;
var barrierSpeed = 150;
var barrierDelay = 1200;

window.onload = function() {	
	game = new Phaser.Game(320, 480, Phaser.AUTO, "");
     game.state.add("PlayGame",playGame);
     game.state.start("PlayGame");
}

var playGame = function(game){};

playGame.prototype = {
	preload: function(){
          game.load.image("ship", "ship.png");
          game.load.image("barrier", "barrier.png");
	},
  	create: function(){
          barrierGroup = game.add.group();
          game.physics.startSystem(Phaser.Physics.ARCADE);
          ship = game.add.sprite(game.width / 2, game.height - 40, "ship");
          ship.anchor.set(0.5);
          game.physics.enable(ship, Phaser.Physics.ARCADE);
          ship.body.allowRotation = false;
          game.input.onDown.add(moveShip);
          game.input.onUp.add(stopShip);
          game.time.events.loop(barrierDelay, function(){
               var position = game.rnd.between(0, 4);
               console.log(position);
               var barrier = new Barrier(game, position, 1);               
               game.add.existing(barrier);
               barrierGroup.add(barrier);
               barrier = new Barrier(game, position + 1, 0);               
               game.add.existing(barrier);
               barrierGroup.add(barrier);
          });  
	},
     update: function(){
          if(ship.x < 0){
               ship.x = game.width;
          }
          if(ship.x > game.width){
               ship.x = 0;
          }
          game.physics.arcade.collide(ship, barrierGroup, function(){
               game.state.start("PlayGame");     
          });
     }
}

function stopShip(){
     ship.body.velocity.x = 0;     
}

function moveShip(e){
     if(e.position.x < game.width / 2){
          speedMult = -1;
     }
     else{
          speedMult = 1;
     }
     ship.body.velocity.x = shipHorizontalSpeed * speedMult;
}

Barrier = function (game, position, anchor) {
	Phaser.Sprite.call(this, game, position * game.width / 5, -20, "barrier");
	game.physics.enable(this, Phaser.Physics.ARCADE);
     this.anchor.set(anchor, 0.5);
};

Barrier.prototype = Object.create(Phaser.Sprite.prototype);
Barrier.prototype.constructor = Barrier;

Barrier.prototype.update = function() {
	this.body.velocity.y = barrierSpeed;
	if(this.y > game.height){
		this.destroy();
	}
};