function preload() {
  this.load.image('sky', require("../assets/sky.png").default);
  this.load.image('ground', require("../assets/platform.png").default);
  this.load.image('star', require("../assets/star.png").default);
  this.load.image('bomb', require("../assets/bomb.png").default);
  this.load.spritesheet('dude',
  require("../assets/dude.png").default,
    { frameWidth: 32, frameHeight: 48 });
}