C++ Contexts类代码示例

CompositeViewer::~CompositeViewer()
{
    OSG_INFO<<"CompositeViewer::~CompositeViewer()"<<std::endl;

    stopThreading();

    Scenes scenes;
    getScenes(scenes);

    for(Scenes::iterator sitr = scenes.begin();
            sitr != scenes.end();
            ++sitr)
    {
        Scene* scene = *sitr;
        if (scene->getDatabasePager())
        {
            scene->getDatabasePager()->cancel();
            scene->setDatabasePager(0);
        }
    }

    Contexts contexts;
    getContexts(contexts);

    // clear out all the previously assigned operations
    for(Contexts::iterator citr = contexts.begin();
            citr != contexts.end();
            ++citr)
    {
        (*citr)->close();
    }

    OSG_INFO<<"finished CompositeViewer::~CompositeViewer()"<<std::endl;
}

Viewer::~Viewer()
{
    //OSG_NOTICE<<"Viewer::~Viewer()"<<std::endl;

    Threads threads;
    getAllThreads(threads);

    OSG_INFO<<"Viewer::~Viewer():: start destructor getThreads = "<<threads.size()<<std::endl;

    stopThreading();

    if (_scene.valid() && _scene->getDatabasePager())
    {
        _scene->getDatabasePager()->cancel();
        _scene->setDatabasePager(0);
    }

    Contexts contexts;
    getContexts(contexts);

    // clear out all the previously assigned operations
    for(Contexts::iterator citr = contexts.begin();
        citr != contexts.end();
        ++citr)
    {
        (*citr)->close();
    }

    //OSG_NOTICE<<"finish Viewer::~Viewer()"<<std::endl;

    getAllThreads(threads);

    OSG_INFO<<"Viewer::~Viewer() end destructor getThreads = "<<threads.size()<<std::endl;
}

void CompositeViewer::setStartTick(osg::Timer_t tick)
{
    _startTick = tick;

    for(RefViews::iterator vitr = _views.begin();
            vitr != _views.end();
            ++vitr)
    {
        (*vitr)->setStartTick(tick);
    }

    Contexts contexts;
    getContexts(contexts,false);

    for(Contexts::iterator citr = contexts.begin();
            citr != contexts.end();
            ++citr)
    {
        osgViewer::GraphicsWindow* gw = dynamic_cast<osgViewer::GraphicsWindow*>(*citr);
        if (gw)
        {
            gw->getEventQueue()->setStartTick(_startTick);
        }
    }
}

Contexts DummyContexts()
{
    Contexts ctxts;
    SWRContext c = { 0 };

    ctxts.insert(std::make_pair(0, (SWRContext)c));
    return ctxts;
}

void CompositeViewer::addView(osgViewer::View* view)
{
    if (!view) return;

    bool alreadyRealized = isRealized();

    bool threadsWereRunning = _threadsRunning;
    if (threadsWereRunning) stopThreading();

    _views.push_back(view);

    view->_viewerBase = this;

    if (view->getSceneData())
    {
        // make sure that existing scene graph objects are allocated with thread safe ref/unref
        if (getThreadingModel()!=ViewerBase::SingleThreaded)
        {
            view->getSceneData()->setThreadSafeRefUnref(true);
        }

        // update the scene graph so that it has enough GL object buffer memory for the graphics contexts that will be using it.
        view->getSceneData()->resizeGLObjectBuffers(osg::DisplaySettings::instance()->getMaxNumberOfGraphicsContexts());
    }

    view->setFrameStamp(_frameStamp.get());

    if (alreadyRealized)
    {
        Contexts contexts;
        if (view->getCamera()->getGraphicsContext())
        {
            contexts.push_back(view->getCamera()->getGraphicsContext());
        }
        for(unsigned int i=0; i<view->getNumSlaves(); ++i)
        {
            if (view->getSlave(i)._camera->getGraphicsContext())
            {
                contexts.push_back(view->getSlave(i)._camera->getGraphicsContext());
            }
        }

        for(Contexts::iterator itr = contexts.begin();
                itr != contexts.end();
                ++itr)
        {
            if (!((*itr)->isRealized()))
            {
                (*itr)->realize();
            }
        }

    }

    if (threadsWereRunning) startThreading();
}

void ExecutableOpHolder::execute( const Contexts &contexts ) const
{
	for ( Contexts::const_iterator cit = contexts.begin(); cit != contexts.end(); cit++ )
	{
		// \todo Implement a way to get the CompoundObject for a given context without modifying the Op's parameter
		// and passing it explicitly in the operate call. Than multi-thread this loop.
		Context::Scope scope( *cit );
		constPointerCast<CompoundParameterHandler>( parameterHandler() )->setParameterValue();
		constPointerCast<Op>( getOp() )->operate();
	}
}

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();
            }
        }

WINGDIAPI BOOL WINAPI wglMakeCurrent(HDC hdc, DHGLRC hglrc)
{
    if (!gCurrentContextSet)
    {
        gCurrentContext = gContexts.end();
        gCurrentContextSet = true;
    }

    if (!hdc || !hglrc)
    {
        gCurrentContext = gContexts.end();
        return 1;
    }

    int rc = (int)hglrc;

    if (gContexts.find(rc) == gCurrentContext)
    {
        return 1;
    }

    gCurrentContext = gContexts.find(rc);

    auto &xCtxt = gContexts[rc];
    OGL::State *pState = xCtxt.pState;

    HWND hWnd = WindowFromDC(hdc);
    RECT rect;
    GetClientRect(hWnd, &rect);

    int width = rect.right - rect.left;
    int height = rect.bottom - rect.top;

    SetOGL(pState);
    OGL::GetDDProcTable().pfnBindContext(OGL::GetDDHandle(), NULL, hWnd, NULL, width, height);

    // according to spec, only set current viewport to draw buffer dimensions if the context hasn't
    // been initialized
    if (!xCtxt.initialized)
    {
        pState->mViewport.x = 0;
        pState->mViewport.y = 0;
        pState->mViewport.width = width;
        pState->mViewport.height = height;
        pState->mScissor.x = 0;
        pState->mScissor.y = 0;
        pState->mScissor.width = width;
        pState->mScissor.height = height;
        xCtxt.initialized = true;
    }
    return 1;
}

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();
            }
        }

void ViewerBase::getWindows(Windows& windows, bool onlyValid)
{
    windows.clear();

    Contexts contexts;
    getContexts(contexts, onlyValid);

    for(Contexts::iterator itr = contexts.begin();
        itr != contexts.end();
        ++itr)
    {
        osgViewer::GraphicsWindow* gw = dynamic_cast<osgViewer::GraphicsWindow*>(*itr);
        if (gw) windows.push_back(gw);
    }
}

void ExecutableRender::execute( const Contexts &contexts ) const
{
	const ScenePlug *scene = inPlug()->getInput<ScenePlug>();
	if( !scene )
	{
		throw IECore::Exception( "No input scene" );
	}

	/// \todo This doesn't belong here. It'll be the responsibility of the Despatchers
	/// to save the script if necessary, and to save it to an alternate location than
	/// the current one.
	scriptNode()->save();

	for( Contexts::const_iterator it = contexts.begin(), eIt = contexts.end(); it != eIt; it++ )
	{
		Context::Scope scopedContext( it->get() );
		ConstCompoundObjectPtr globals = scene->globalsPlug()->getValue();

		createDisplayDirectories( globals );

		IECore::RendererPtr renderer = createRenderer();		
		outputOptions( globals, renderer );
		outputCamera( scene, globals, renderer );
		{
			WorldBlock world( renderer );

			outputLights( scene, globals, renderer ); 
			outputWorldProcedural( scene, renderer );
		}
		
		std::string systemCommand = command();
		if( systemCommand.size() )
		{
			const ApplicationRoot *applicationRoot = scene->ancestor<ApplicationRoot>();
			if( applicationRoot && applicationRoot->getName() == "gui" )
			{
				/// \todo We need this weird background execution behaviour because we
				/// don't want to block the ui while rendering, but really the LocalDespatcher
				/// should be responsible for launching a separate process to do the execution
				/// from anyway.
				systemCommand += "&";
			}
			
			system( systemCommand.c_str() );
		}
	}
}

WINGDIAPI HDC WINAPI wglGetCurrentDC(VOID)
{
    if (!gCurrentContextSet)
    {
        gCurrentContext = gContexts.end();
        gCurrentContextSet = true;
    }

    if (gCurrentContext == gContexts.end())
    {
        return NULL;
    }
    else
    {
        return gCurrentContext->second.hdc;
    }
}

Viewer::~Viewer()
{
    //OSG_NOTICE<<"Viewer::~Viewer()"<<std::endl;

    Threads threads;
    getAllThreads(threads);

    OSG_INFO<<"Viewer::~Viewer():: start destructor getThreads = "<<threads.size()<<std::endl;

    stopThreading();

    if (_scene.valid() && _scene->getDatabasePager())
    {
        _scene->getDatabasePager()->cancel();
        _scene->setDatabasePager(0);
    }

    Contexts contexts;
    getContexts(contexts);

    // clear out all the previously assigned operations
    for(Contexts::iterator citr = contexts.begin();
        citr != contexts.end();
        ++citr)
    {
        osg::GraphicsContext* gc = *citr;

        // Run destroy operation on each context before closing it
        if (_cleanUpOperation.valid() && gc->valid())
        {
            gc->makeCurrent();

            (*_cleanUpOperation)(gc);

            gc->releaseContext();
        }

        gc->close();
    }

    //OSG_NOTICE<<"finish Viewer::~Viewer()"<<std::endl;

    getAllThreads(threads);

    OSG_INFO<<"Viewer::~Viewer() end destructor getThreads = "<<threads.size()<<std::endl;
}

void ViewerBase::checkWindowStatus(const Contexts& contexts)
{
    if (contexts.size()==0)
    {
        _done = true;
        if (areThreadsRunning()) stopThreading();
    }
}

WINGDIAPI HGLRC WINAPI wglGetCurrentContext(VOID)
{
    if (!gCurrentContextSet)
    {
        gCurrentContext = gContexts.end();
        gCurrentContextSet = true;
    }

    if (gCurrentContext == gContexts.end())
    {
        return NULL;
    }
    else
    {
        return reinterpret_cast<HGLRC>(gCurrentContext->first);
    }
}