C++ Contexts::empty方法代码示例

void Viewer::realize()
{
    //OSG_INFO<<"Viewer::realize()"<<std::endl;
	// 保存了osg::GraphicsContext指针的向量组
    Contexts contexts;
	// 获取所有的图形上下文，并保存到这个向量组中来
    getContexts(contexts);
	// 如果没有得到任何图形上下文的话，就说明仿真系统还没有合适的显示平台
	// 这个时候就需要创建一个缺省的GraphicsContext设备，并再次执行getContexts
    if (contexts.empty())
    {
        OSG_INFO<<"Viewer::realize() - No valid contexts found, setting up view across all screens."<<std::endl;

        // no windows are already set up so set up a default view
		// 创建缺省GraphicsContext设备的方法有以下几种：
		// 读取OSG_CONFIG_FILE环境变量的内容，如果用户在这个环境变量中定义了一个文件路径的话
		// 使用配置文件设置当前视景器
        const char* ptr = 0;
        if ((ptr = getenv("OSG_CONFIG_FILE")) != 0)
        {
            readConfiguration(ptr);
        }
        else
        {
            int screenNum = -1;
            if ((ptr = getenv("OSG_SCREEN")) != 0)
            {
                if (strlen(ptr)!=0) screenNum = atoi(ptr);
                else screenNum = -1;
            }

            int x = -1, y = -1, width = -1, height = -1;
            if ((ptr = getenv("OSG_WINDOW")) != 0)
            {
                std::istringstream iss(ptr);
                iss >> x >> y >> width >> height;
            }

            if (width>0 && height>0)
            {
                if (screenNum>=0) setUpViewInWindow(x, y, width, height, screenNum);
                else setUpViewInWindow(x,y,width,height);
            }
            else if (screenNum>=0)
            {
                setUpViewOnSingleScreen(screenNum);
            }
            else
            {
                setUpViewAcrossAllScreens();
            }
        }

void Viewer::realize()
{
    //OSG_INFO<<"Viewer::realize()"<<std::endl;

    setCameraWithFocus(0);

    Contexts contexts;
    getContexts(contexts);

    if (contexts.empty())
    {
        OSG_INFO<<"Viewer::realize() - No valid contexts found, setting up view across all screens."<<std::endl;

        // no windows are already set up so set up a default view

        const char* ptr = 0;
        if ((ptr = getenv("OSG_CONFIG_FILE")) != 0)
        {
            readConfiguration(ptr);
        }
        else
        {
            int screenNum = -1;
            if ((ptr = getenv("OSG_SCREEN")) != 0)
            {
                if (strlen(ptr)!=0) screenNum = atoi(ptr);
                else screenNum = -1;
            }

            int x = -1, y = -1, width = -1, height = -1;
            if ((ptr = getenv("OSG_WINDOW")) != 0)
            {
                std::istringstream iss(ptr);
                iss >> x >> y >> width >> height;
            }

            if (width>0 && height>0)
            {
                if (screenNum>=0) setUpViewInWindow(x, y, width, height, screenNum);
                else setUpViewInWindow(x,y,width,height);
            }
            else if (screenNum>=0)
            {
                setUpViewOnSingleScreen(screenNum);
            }
            else
            {
                setUpViewAcrossAllScreens();
            }
        }

ViewerBase::ThreadingModel ViewerBase::suggestBestThreadingModel()
{
    const char* str = getenv("OSG_THREADING");
    if (str)
    {
        if (strcmp(str,"SingleThreaded")==0) return SingleThreaded;
        else if (strcmp(str,"CullDrawThreadPerContext")==0) return CullDrawThreadPerContext;
        else if (strcmp(str,"DrawThreadPerContext")==0) return DrawThreadPerContext;
        else if (strcmp(str,"CullThreadPerCameraDrawThreadPerContext")==0) return CullThreadPerCameraDrawThreadPerContext;
    }

    Contexts contexts;
    getContexts(contexts);

    if (contexts.empty()) return SingleThreaded;

#if 0
    // temporary hack to disable multi-threading under Windows till we find good solutions for
    // crashes that users are seeing.
    return SingleThreaded;
#endif

    Cameras cameras;
    getCameras(cameras);

    if (cameras.empty()) return SingleThreaded;


    int numProcessors = OpenThreads::GetNumberOfProcessors();

    if (contexts.size()==1)
    {
        if (numProcessors==1) return SingleThreaded;
        else return DrawThreadPerContext;
    }

#if 1
    if (numProcessors >= static_cast<int>(cameras.size()+contexts.size()))
    {
        return CullThreadPerCameraDrawThreadPerContext;
    }
#endif

    return DrawThreadPerContext;
}

void CompositeViewer::realize()
{
    //OSG_INFO<<"CompositeViewer::realize()"<<std::endl;

    setCameraWithFocus(0);

    if (_views.empty())
    {
        OSG_NOTICE<<"CompositeViewer::realize() - No views to realize."<<std::endl;
        _done = true;
        return;
    }

    Contexts contexts;
    getContexts(contexts);

    if (contexts.empty())
    {
        OSG_INFO<<"CompositeViewer::realize() - No valid contexts found, setting up view across all screens."<<std::endl;

        // no windows are already set up so set up a default view
        _views[0]->setUpViewAcrossAllScreens();

        getContexts(contexts);
    }

    if (contexts.empty())
    {
        OSG_NOTICE<<"CompositeViewer::realize() - failed to set up any windows"<<std::endl;
        _done = true;
        return;
    }

    unsigned int maxTexturePoolSize = osg::DisplaySettings::instance()->getMaxTexturePoolSize();
    unsigned int maxBufferObjectPoolSize = osg::DisplaySettings::instance()->getMaxBufferObjectPoolSize();

    for(Contexts::iterator citr = contexts.begin();
            citr != contexts.end();
            ++citr)
    {
        osg::GraphicsContext* gc = *citr;

        // set the pool sizes, 0 the default will result in no GL object pools.
        gc->getState()->setMaxTexturePoolSize(maxTexturePoolSize);
        gc->getState()->setMaxBufferObjectPoolSize(maxBufferObjectPoolSize);

        gc->realize();

        if (_realizeOperation.valid() && gc->valid())
        {
            gc->makeCurrent();

            (*_realizeOperation)(gc);

            gc->releaseContext();
        }
    }

    // attach contexts to _incrementalCompileOperation if attached.
    if (_incrementalCompileOperation) _incrementalCompileOperation->assignContexts(contexts);


    bool grabFocus = true;
    if (grabFocus)
    {
        for(Contexts::iterator citr = contexts.begin();
                citr != contexts.end();
                ++citr)
        {
            osgViewer::GraphicsWindow* gw = dynamic_cast<osgViewer::GraphicsWindow*>(*citr);
            if (gw)
            {
                gw->grabFocusIfPointerInWindow();
            }
        }
    }


    startThreading();

    // initialize the global timer to be relative to the current time.
    osg::Timer::instance()->setStartTick();

    // pass on the start tick to all the associated eventqueues
    setStartTick(osg::Timer::instance()->getStartTick());

    if (osg::DisplaySettings::instance()->getCompileContextsHint())
    {
        int numProcessors = OpenThreads::GetNumberOfProcessors();
        int processNum = 0;

        for(unsigned int i=0; i<= osg::GraphicsContext::getMaxContextID(); ++i)
        {
            osg::GraphicsContext* gc = osg::GraphicsContext::getOrCreateCompileContext(i);

            if (gc)
            {
                gc->createGraphicsThread();
                gc->getGraphicsThread()->setProcessorAffinity(processNum % numProcessors);
                gc->getGraphicsThread()->startThread();
//.........这里部分代码省略.........

//.........这里部分代码省略.........
        }
    }

    if (_threadingModel==CullDrawThreadPerContext)
    {
        _startRenderingBarrier = 0;
        _endRenderingDispatchBarrier = 0;
        _endDynamicDrawBlock = 0;
    }
    else if (_threadingModel==DrawThreadPerContext ||
             _threadingModel==CullThreadPerCameraDrawThreadPerContext)
    {
        _startRenderingBarrier = 0;
        _endRenderingDispatchBarrier = 0;
        _endDynamicDrawBlock = new osg::EndOfDynamicDrawBlock(numViewerDoubleBufferedRenderingOperation);

#ifndef OSGUTIL_RENDERBACKEND_USE_REF_PTR
        if (!osg::Referenced::getDeleteHandler()) osg::Referenced::setDeleteHandler(new osg::DeleteHandler(2));
        else osg::Referenced::getDeleteHandler()->setNumFramesToRetainObjects(2);
#endif
    }

    if (numThreadsOnStartBarrier>1)
    {
        _startRenderingBarrier = new osg::BarrierOperation(numThreadsOnStartBarrier, osg::BarrierOperation::NO_OPERATION);
    }

    if (numThreadsOnEndBarrier>1)
    {
        _endRenderingDispatchBarrier = new osg::BarrierOperation(numThreadsOnEndBarrier, _endBarrierOperation);
    }


    osg::ref_ptr<osg::BarrierOperation> swapReadyBarrier = contexts.empty() ? 0 : new osg::BarrierOperation(contexts.size(), osg::BarrierOperation::NO_OPERATION);

    osg::ref_ptr<osg::SwapBuffersOperation> swapOp = new osg::SwapBuffersOperation();

    typedef std::map<OpenThreads::Thread*, int> ThreadAffinityMap;
    ThreadAffinityMap threadAffinityMap;

    unsigned int processNum = 1;
    for(citr = contexts.begin();
        citr != contexts.end();
        ++citr, ++processNum)
    {
        osg::GraphicsContext* gc = (*citr);

        if (!gc->isRealized())
        {
            OSG_INFO<<"ViewerBase::startThreading() : Realizng window "<<gc<<std::endl;
            gc->realize();
        }

        gc->getState()->setDynamicObjectRenderingCompletedCallback(_endDynamicDrawBlock.get());

        // create the a graphics thread for this context
        gc->createGraphicsThread();

        if (affinity) gc->getGraphicsThread()->setProcessorAffinity(processNum % numProcessors);
        threadAffinityMap[gc->getGraphicsThread()] = processNum % numProcessors;

        // add the startRenderingBarrier
        if (_threadingModel==CullDrawThreadPerContext && _startRenderingBarrier.valid()) gc->getGraphicsThread()->add(_startRenderingBarrier.get());

        // add the rendering operation itself.
        gc->getGraphicsThread()->add(new osg::RunOperations());