GN53 Multithreading Example

//Data Members

typedef std::array<pixel_buffer_object, 5> array_t;
typedef std::vector<vu8> work_t;

const int                 m_w;
const int                 m_h;
const int                 m_bytes;
array_t                   m_pbos;
array_t::iterator         m_pbo_iter = m_pbos.begin();
boost::thread             m_thread;
boost::atomic<u32>        m_atomic_remaining{0};
boost::mutex              m_shared_mutex;
work_t                    m_shared_work;
boost::condition_variable m_shared_cv;


//Producer

template <typename... Args> void send_work(Args&&... args) {
    boost::unique_lock<boost::mutex> ul(m_shared_mutex);

    const bool must_notify = m_shared_work.empty();

    m_shared_work.emplace_back(std::forward<Args>(args)...);

    ul.unlock();

    if (must_notify) {
        m_shared_cv.notify_one();
    }
}


//Consumer

void worker_thread() {
    u32 highest_num = highest_numbered_screenshot();

    for (work_t local_work; ; local_work.clear()) {
        boost::unique_lock<boost::mutex> ul(m_shared_mutex);

        while (m_shared_work.empty()) {
            m_shared_cv.wait(ul);
        }

        m_shared_work.swap(local_work);

        ul.unlock();

        for (auto& v : local_work) {
            if (v.empty()) {
                return;
            }

            erase_alpha(v);

            write_screenshot(m_w, m_h, v, ++highest_num);

            --m_atomic_remaining;
        }
    }
}