问赋值后未定义的变量

EN

var game = new Phaser.Game(
  800,
  600,
  Phaser.AUTO,
  'game',
  { init: init,
    preload: preload, 
    create: create, 
    update: update,
    randomizeWin: randomizeWin,
    myMethod: myMethod
  }
);

function init() {
  this.sss=56;
  this.marginX=150;
  this.marinY=100;    
}

function preload() {
  var wood = game.load.image('wood', 'assets/wood.jpg');
  randomizeWin();
  console.log(this.winY);
}

function create() {
  this.p=[];
  for(var i=0;i<3;i++) {
    this.p[i]=[];
    for(var j=0;j<3;j++){
      this.p[i][j]= game.add.sprite(this.marginX+i*170, this.marinY+j*170, 'wood');
      this.p[i][j].scale.x=0.2;
      this.p[i][j].scale.y=0.2;
      this.p[i][j].anchor.setTo(.5,.5);
      this.p[i][j].inputEnabled = true;
      this.p[i][j].input.useHandCursor = true;
      this.p[i][j].events.onInputDown.add(myMethod, this);
    }   
  }
}

function update() {
}

function myMethod(sprite) {
  console.log(this.p[this.winX][this.winY]==sprite);// winX is undefined here why??
  if(this.p[this.winX][this.winY]==sprite){
    game.add.tween(sprite.scale).to ({
      x: sprite.scale.x * -1,
      // y: sprite.scale.y * -1
    }, 1000, Phaser.Easing.Bounce.Out, true);
  }
}

function randomizeWin() {
  console.log("rand");
  this.winX = Math.floor(Math.random() * 3);
  this.winY = Math.floor(Math.random() * 3);
}