Function main

src/examples/rpp/sfml/snake/main.cpp:36–85

#include <iostream>

int main()
{
    auto             window_size = get_window_size(s_rows_count, s_columns_count);
    sf::RenderWindow window(sf::VideoMode(window_size.x, window_size.y), "Snake");

    const auto events   = get_events_observable(window) | rpp::ops::publish();
    const auto presents = get_presents_stream(events);

    auto   start        = rpp::schedulers::clock_type::now();
    size_t frames_delta = 0;
    presents.subscribe([&window](const present_event&) {
        window.display();
        window.clear(sf::Color{0, 128, 0});
    });

    presents | rpp::ops::observe_on(rpp::schedulers::new_thread{}) | rpp::ops::subscribe([&start, &frames_delta](const present_event& p) {
        const auto diff = p.frame_number - frames_delta;
        if (diff > 50)
        {
            const auto now = rpp::schedulers::clock_type::now();
            std::cout << "FPS: " << ((static_cast<double>(diff) / static_cast<double>(std::chrono::duration_cast<std::chrono::nanoseconds>(now - start).count())) * 1000000000.0) << std::endl;
            frames_delta = p.frame_number;
            start        = now;
        }
    });

    get_shapes_to_draw(events).subscribe([&window](const auto& shape) {
        window.draw(shape);
    });

    const auto root_subscription = events
                                 | rpp::ops::ref_count()
                                 | rpp::ops::filter([](const CustomEvent& ev) { return std::holds_alternative<sf::Event>(ev); })
                                 | rpp::ops::filter([](const CustomEvent& ev) {
                                       return std::get<sf::Event>(ev).type == sf::Event::Closed;
                                   })
                                 | rpp::ops::take(1)
                                 | rpp::ops::subscribe_with_disposable([&](const auto&) {
                                       window.close();
                                   });

    // this one will be blocking call and it will unblock when close requested
    while (!root_subscription.is_disposed())
    {
        while (g_run_loop.is_any_ready_schedulable())
            g_run_loop.dispatch();
    }

    return EXIT_SUCCESS;
}