save screen in playground.js

game.js

/* This will make you a screenshot for later usage whenever you want */

ENGINE.Game = {

  showOptionsScreen: function() {
    
    app.screenshot = this.app.layer.cache();
    app.setState(ENGINE.Options);

  }

};

/* 
  anytime later in the code 
  use screenshot for cool transitional effects
  involving previous screen
  or displaying previous screen as a background of current menu
*/

app.layer.drawImage(app.screenshot, 0, 0);