窗口

窗口基类：用于被不同平台的窗口子类继承

class Window
{
public:
	using EventCallbackFn = std::function<void(Event&)>;

	virtual ~Window() {}
	virtual void OnUpdate() = 0;

	virtual unsigned int GetWidth() const = 0;  
	virtual unsigned int GetHeight() const = 0;

	virtual void SetEventCallback(const EventCallbackFn& callback) = 0;

	virtual void SetVSync(bool enabled) = 0; 
	virtual bool IsVSync() const = 0;

	static Window* Create(const WindowProps& props = WindowProps());
};

窗口与事件系统：