javascript - 扩展 pixi.js sprite 并在构造函数中访问父级的属性

Question

我正在尝试扩展 pixi.js 的 sprite 类并在我的子类构造函数中设置它的position.x 属性

var Ship = function(x, y, image, focused) {
    PIXI.Sprite.fromImage.call(this, image);

    this.x = x;
    this.y = y;
    this.image = image;
    this.focused = typeof focused != 'undefined' ? focused : false;

    this.position.x = window.width/2;
};

Ship.prototype = Object.create(PIXI.Sprite.fromImage.prototype);

Ship.prototype.constructor = Ship;

但是，我不断收到错误“Uncaught TypeError:无法设置未定义的属性 'x'”

this.position.x = window.width/2;

我相信在调用 Object.create() 之前我无法访问父类的属性...那么执行此操作的正确方法是什么？

Answer 1

Ship.prototype = Object.create(PIXI.Sprite.prototype);

应该可以解决问题!