MacBook Pro 8,1 Disco Lights

disco.cpp

#include <chrono>
#include <cmath>
#include <fstream>
#include <iostream>
#include <string>
#include <thread>
#include <vector>

struct light_dev {
    virtual void set_brighness(float fraction) = 0;
};

struct led_dev : light_dev {
    led_dev(std::string folder) : folder(folder) {
        std::ifstream mfs(folder + "/max_brightness");
        mfs >> max;
        mfs.close();

        std::cout << folder << "  max=" << max << std::endl;
    }

    std::string folder;
    int max;

    virtual void set_brighness(float fraction) override {
        std::ofstream ofs(folder + "/brightness");
        ofs << (int)std::round(fraction * max) << std::endl;
        ofs.close();
    }
};

struct spdif_dev : light_dev {
    int status;

    virtual void set_brighness(float fraction) override {
        int s = (int)std::round(fraction);
        if (s != status) {
            status = s;
            std::string str = status ? "on" : "off";
            system(("amixer set IEC958,16 " + str).c_str());
        }
    }
};

int main() {
    using namespace std::chrono_literals;

    std::vector<light_dev*> lights = {
        new led_dev("/sys/class/leds/smc::kbd_backlight"),
        new led_dev("/sys/class/leds/input6::capslock"),
        new led_dev("/sys/class/backlight/intel_backlight"), new spdif_dev()};

    std::vector<double> time_factors = {2.0, 8.0, 0.1, 10};

    auto start = std::chrono::system_clock::now();
    while (true) {
        auto end = std::chrono::system_clock::now();
        std::chrono::duration<double> dur = (end - start);
        double time = dur.count();

        for (int i = 0; i < lights.size(); ++i) {
            float s = std::sin(time * 5.0f * time_factors[i]);
            s *= s;
            lights[i]->set_brighness(s);
        }

        std::this_thread::sleep_for(50ms);
    }

    return 0;
}