smiledetect_tbb_2.cpp

//...
    if( capture.isOpened() )
    {
        //...

        tbb::concurrent_bounded_queue<ProcessingChainData *> guiQueue;
        guiQueue.set_capacity(2); // TBB NOTE: flow control so the pipeline won't fill too much RAM
        auto pipelineRunner = thread( detectAndDrawTBB, ref(capture), ref(guiQueue), ref(cascade), ref(nestedCascade), scale, tryflip );

        //...    

        // TBB NOTE: GUI is executed in main thread
        ProcessingChainData *pData=0;
        for(;! done;)
        {
            if (guiQueue.try_pop(pData))
            {
                char c = (char)waitKey(1);
                if( c == 27 || c == 'q' || c == 'Q' )
                {
                    done = true;
                }
                imshow( "result", pData->img );
                delete pData;
                pData = 0;
            }
        }
        double tfreq = getTickFrequency();
        double secs = ((double) getTickCount() - startTime)/tfreq;
        cout << "Execution took " << fixed << secs << " seconds." << endl;
        // TBB NOTE: flush the queue after marking 'done'
        do
        {
            delete pData;
        } while (guiQueue.try_pop(pData));
        pipelineRunner.join(); // TBB NOTE: wait for the pipeline to finish
    }
//...