轉自：http://blog.csdn.net/zhy_cheng/article/details/9116479
cocos2d-x引擎在內部實現了一個龐大的主循環，每幀之間更新界面，如果耗時的操作放到了主線程中，游戲的界面就會卡，這是不能容忍的，游戲最基本的條件就是流暢性，這就是為什么游戲開發選擇C++的原因。另外現在雙核手機和四核手機越來越普遍了，是時候使用多線程來挖掘硬件的潛力了。
1.環境搭建
cocos2d-x中的多線程使用pthread就可以實現跨平台，而且也不是很難理解。使用pthread需要先配置一下工程。右擊工程----->屬性----->配置屬性---->鏈接器----->輸入---->附加依賴項中添加pthreadVCE2.lib，如下圖
接着添加附加包含目錄，右擊項目，屬性----->C/C++---->常規----->附加包含目錄加入pthread頭文件所在的目錄
這樣，環境就搭建起來了。
2.多線程的使用
使用pthread來實現多線程，最重要的一個函數是
PTW32_DLLPORT int PTW32_CDECL pthread_create (pthread_t * tid,//線程的標示 const pthread_attr_t * attr, //創建線程的參數 void *(*start) (void *), //入口函數的指針 void *arg); //傳遞給線程的數據
在HelloWorldScene.h文件中
pthread_t pidrun,pidgo; static void* th_run(void *r); static void* th_go(void *r);
定義了兩個函數和兩個線程的標識。
然后自定義了一個類，用於給線程傳遞數據。Student類如下：
#pragma once #include <string> class Student { public: Student(void); Student(std::string name,int age,std::string sex); ~Student(void); std::string name; int age; std::string sex; };
源文件如下
#include "Student.h" #include "cocos2d.h" Student::Student(void) { } Student::~Student(void) { cocos2d::CCLog("delete data"); } Student::Student(std::string name,int age,std::string sex) { this->name=name; this->age=age; this->sex=sex; }
在退出菜單的回調函數中啟動兩個線程：
void HelloWorld::menuCloseCallback(CCObject* pSender) { Student *temp=new Student(std::string("zhycheng"),23,std::string("male")); pthread_mutex_init(&mutex,NULL); pthread_create(&pidrun,NULL,th_run,temp);//啟動線程 pthread_create(&pidgo,NULL,th_go,0); }
可以看到，將Student的指針傳遞給了pidrun線程，那么在pidrun線程中獲得Student信息如下：
Student *s=(Student*)(r); CCLog("name is %s,and age is %d,sex is %s",s->name.c_str(),s->age,s->sex.c_str()); delete s;
3.線程同步
使用了線程，必然就要考慮到線程同步，不同的線程同時訪問資源的話，訪問的順序是不可預知的，會造成不可預知的結果。
這里使用pthread_mutex_t來實現同步，下面我來演示一下使用多線程實現賣票系統。賣票的時候，是由多個窗口同時賣票，這里要做到一張票不要賣出去兩次，不要出現有票卻無法賣的結果。
在線程函數th_run和th_go中來賣票，票的數量是一個全局變量，每賣出去一張票，就將票的數量減一。其中同步的pthread_mutex_t也是一個全局變量，就用它來實現線程同步。
void* HelloWorld::th_run(void *r) { Student *s=(Student*)(r); CCLog("name is %s,and age is %d,sex is %s",s->name.c_str(),s->age,s->sex.c_str()); delete s; while(true) { pthread_mutex_lock(&mutex); if(ticket>0) { CCLog("thread run sell %d",ticket); ticket--; pthread_mutex_unlock(&mutex); } else { pthread_mutex_unlock(&mutex); break; } Sleep(1); //Usleep(10); } return NULL; }
void* HelloWorld::th_go(void *r) { while(true) { pthread_mutex_lock(&mutex); if(ticket>0) { CCLog("thread go sell %d",ticket); ticket--; pthread_mutex_unlock(&mutex); } else { pthread_mutex_unlock(&mutex); break; } Sleep(1); } return NULL; }
mutex被鎖定后，其他線程若再想鎖定mutex的話，必須等待，當該線程釋放了mutex之后，其他線程才能鎖定mutex。Sleep()函數可以使得該線程休眠，單位是毫秒。下面是賣票的結果：
name is zhycheng,and age is 23,sex is male delete data thread run sell 100 thread run sell 99 thread go sell 98 thread go sell 97 thread run sell 96 thread go sell 95 thread go sell 94 thread run sell 93 thread go sell 92 thread run sell 91 thread go sell 90 thread go sell 89 thread run sell 88 thread go sell 87 thread run sell 86 thread go sell 85 thread run sell 84 thread go sell 83 thread run sell 82 thread go sell 81 thread run sell 80 thread go sell 79 thread run sell 78 thread go sell 77 thread run sell 76 thread go sell 75 thread run sell 74 thread go sell 73 thread run sell 72 thread go sell 71 thread run sell 70 thread go sell 69 thread go sell 68 thread run sell 67 thread go sell 66 thread run sell 65 thread go sell 64 thread run sell 63 thread go sell 62 thread run sell 61 thread go sell 60 thread run sell 59 thread go sell 58 thread run sell 57 thread go sell 56 thread run sell 55 thread go sell 54 thread run sell 53 thread run sell 52 thread go sell 51 thread run sell 50 thread go sell 49 thread run sell 48 thread go sell 47 thread run sell 46 thread go sell 45 thread run sell 44 thread run sell 43 thread go sell 42 thread run sell 41 thread run sell 40 thread go sell 39 thread run sell 38 thread run sell 37 thread run sell 36 thread run sell 35 thread go sell 34 thread run sell 33 thread run sell 32 thread go sell 31 thread run sell 30 thread run sell 29 thread run sell 28 thread run sell 27 thread run sell 26 thread run sell 25 thread go sell 24 thread run sell 23 thread go sell 22 thread go sell 21 thread run sell 20 thread go sell 19 thread run sell 18 thread run sell 17 thread go sell 16 thread run sell 15 thread go sell 14 thread go sell 13 thread run sell 12 thread go sell 11 thread go sell 10 thread run sell 9 thread go sell 8 thread run sell 7 thread go sell 6 thread go sell 5 thread run sell 4 thread go sell 3 thread run sell 2 thread run sell 1
可以看到，這個打印結果正確無誤。如果不加mutex會是什么樣的結果呢，我將線程同步的mutex注釋掉，輸出的結果為：
name is zhycheng,and age is 23,sex is male delete data thread run sell 100 thread run sell 99 thread run sell 98 thread go sell 97 thread run sell 96 thread go sell 95 thread run sell 94 thread go sell 94 thread run sell 92 thread run sell 91 thread go sell 90 thread run sell 89 thread go sell 88 thread run sell 87 thread run sell 86 thread go sell 86 thread go sell 84 thread run sell 83 thread go sell 82 thread run sell 81 thread go sell 80 thread run sell 79 thread run sell 78 thread go sell 77 thread run sell 76 thread run sell 75 thread go sell 74 thread run sell 73 thread go sell 72 thread run sell 71 thread go sell 70 thread go sell 69 thread run sell 68 thread go sell 67 thread go sell 66 thread run sell 65 thread go sell 64 thread go sell 63 thread run sell 62 thread go sell 61 thread run sell 60 thread run sell 59 thread run sell 58 thread run sell 57 thread run sell 56 thread run sell 55 thread go sell 54 thread run sell 54 thread go sell 52 thread run sell 52 thread go sell 50 thread run sell 50 thread go sell 49 thread run sell 47 thread go sell 47 thread go sell 45 thread run sell 45 thread run sell 43thread go sell 43 thread run sell 41 thread go sell 41 thread go sell 39 thread run sell 39 thread run sell 37 thread go sell 37 thread go sell 35 thread run sell 35 thread go sell 33thread run sell 33 thread go sell 31thread run sell 31 thread go sell 29 thread run sell 29 thread go sell 27 thread run sell 27 thread go sell 25 thread run sell 25 thread run sell 23 thread go sell 23 thread run sell 21 thread go sell 21 thread go sell 19 thread run sell 19 thread run sell 17 thread go sell 17 thread go sell 15 thread run sell 15 thread run sell 13 thread go sell 13 thread run sell 11thread go sell 11 thread go sell 9 thread run sell 9 thread run sell 7 thread go sell 7 thread go sell 5thread run sell 5 thread go sell 3 thread run sell 3 thread go sell 1 thread run sell 1
可以看到，有的票賣了兩次，有的票就沒賣。
4.注意
1.Sleep()函數是使得線程休眠的函數，這個函數不跨平台，僅僅在windows上能用，其他平台使用usleep。
2.在非主線程中不能使用cocos2d-x管理內存的CCObject::retain(), CCObject::release() 者CCObject::autorelease()，因為CCAutoreleasePool不是線程安全的，OPENGL的上下文也不是線程安全的，所以不要再非主線程中使用cocos2d-x的API和UI操作。