cocos2dx实现全局游戏公告

来源：互联网发布：梦想小镇布局知乎编辑：程序博客网时间：2024/05/24 03:22

最刚开始分平台调用原生的提示，但是由于项目之后要显示的内容变的复杂，只好研究一下全局的游戏公告该怎么显示了。

直接addChild的是行不通的，或者处理起来比较繁琐，因为每次切换scene都会清空。

研究了一下cocos2dx的渲染机制。

入口：

CCApplication::sharedApplication()->run()

CCDirecor会周期执行一个mainLoop

int CCApplication::run(){    PVRFrameEnableControlWindow(false);    // Main message loop:    MSG msg;    LARGE_INTEGER nFreq;    LARGE_INTEGER nLast;    LARGE_INTEGER nNow;    QueryPerformanceFrequency(&nFreq);    QueryPerformanceCounter(&nLast);    // Initialize instance and cocos2d.    if (!applicationDidFinishLaunching())    {        return 0;    }    CCEGLView* pMainWnd = CCEGLView::sharedOpenGLView();    pMainWnd->centerWindow();    ShowWindow(pMainWnd->getHWnd(), SW_SHOW);    while (1)    {        if (! PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))        {            // Get current time tick.            QueryPerformanceCounter(&nNow);            // If it's the time to draw next frame, draw it, else sleep a while.            if (nNow.QuadPart - nLast.QuadPart > m_nAnimationInterval.QuadPart)            {                nLast.QuadPart = nNow.QuadPart;                CCDirector::sharedDirector()->mainLoop();            }            else            {                Sleep(0);            }            continue;        }        if (WM_QUIT == msg.message)        {            // Quit message loop.            break;        }        // Deal with windows message.        if (! m_hAccelTable || ! TranslateAccelerator(msg.hwnd, m_hAccelTable, &msg))        {            TranslateMessage(&msg);            DispatchMessage(&msg);        }    }    return (int) msg.wParam;}

mainLoop里面又会draw当前的scene：

void CCDisplayLinkDirector::mainLoop(void){    if (m_bPurgeDirecotorInNextLoop)    {        m_bPurgeDirecotorInNextLoop = false;        purgeDirector();    }    else if (! m_bInvalid)     {         drawScene();              // release the objects         CCPoolManager::sharedPoolManager()->pop();             }}

重点是在drawScene里面有一个m_pNotificationNode：

// Draw the Scenevoid CCDirector::drawScene(void){    // calculate "global" dt    calculateDeltaTime();    //tick before glClear: issue #533    if (! m_bPaused)    {        m_pScheduler->update(m_fDeltaTime);    }    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);    /* to avoid flickr, nextScene MUST be here: after tick and before draw.     XXX: Which bug is this one. It seems that it can't be reproduced with v0.9 */    if (m_pNextScene)    {        setNextScene();    }    kmGLPushMatrix();    // draw the scene    if (m_pRunningScene)    {        m_pRunningScene->visit();    }    // draw the notifications node    if (m_pNotificationNode)    {        m_pNotificationNode->visit();    }        if (m_bDisplayStats)    {        showStats();    }        kmGLPopMatrix();    m_uTotalFrames++;    // swap buffers    if (m_pobOpenGLView)    {        m_pobOpenGLView->swapBuffers();    }        if (m_bDisplayStats)    {        calculateMPF();    }}

查看m_pNotificationNode定义

 /* This object will be visited after the scene. Useful to hook a notification node */    CCNode *m_pNotificationNode;

所以创建一个游戏公告层：

NoticeBoard* noticeBoard = NoticeBoard::create();pDirector->setNotificationNode(noticeBoard);

这样两行代码就可以实现全局的游戏公告，不受切换场景的影响了。

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