The application of design pattern in game--observer mode (10)

The observer pattern may seem strange, but it can be said that the observer pattern is the most used mode in the game, even more frequent than the singleton pattern, and the code that wants to write good games must understand where in the game those places use the observer pattern, and who the subscribers of each observer are.

Most MMORPG players are a while loop that updates the viewer by updating Subscribers with these while loops. For example, we have a player's subscribers, each player is an observer, I just need to update the subscribers to update each observer. We each player has a lot of buff, our players are subscribers, each buff is the observer, so that when the player gets updated, we have each buff can get updates.

Let's look at the observer pattern, the observer pattern (sometimes called the publish-subscribe subscribe> pattern, the model-view view> mode, the source-listener listener> mode, or the slave mode), which is one of the software design patterns. In this mode, a target object manages all the observer objects that are dependent on it and proactively notifies when its own state changes. This is usually done by calling the methods provided by each observer.

Is the flowchart of the Observer pattern:

The code is as follows:

//MVC.cpp: Defines the entry point of the console application. //#include "stdafx.h"#include <iostream>#include <string>#include <sstream>#include <list>using namespace STD;classSubject;classObserver;classobserver{ Public: ~observer () {};Virtual voidUpdate () =0;};classBuff: Publicobserver{ Public: Buff (subject* host,intID): M_host (Host), m_id (ID) {}Virtual voidUpdate () {cout<<m_id<<"Buff Update"<<endl; } subject* M_host;intm_id;};classsubject{ Public: ~subject () {};voidAttach (observer* value) {observerlist.push_back (value); }voidDetach (observer* value) {observerlist.remove (value); }voidNotify () { for( list<Observer*>:: Iterator iter = Observerlist.begin (); Iter! = Observerlist.end ();        ++iter) {(*iter)->update (); }    } list<Observer*>Observerlist;};voidMain () {auto_ptr<Subject> Subject (NewSubject ());auto_ptr<Buff> Buff_one (NewBuff (Subject.get (),1));auto_ptr<Buff> Buff_two (NewBuff (Subject.get (),2));    Subject->attach (Buff_one.get ());    Subject->attach (Buff_two.get ()); Subject->notify ();}

The results are as follows:

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The application of design pattern in game--observer mode (10)