FluidSimCpp/tools/audio_capture.cpp

#include "FluidSim/Scenario.hpp"
#include "FluidSim/TwoStrokeScenario.hpp"
#include <algorithm>
#include <cmath>
#include <cstdint>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <memory>
#include <string>
#include <type_traits>
using namespace fluidsim::port;
namespace {
class Wav {
    std::ofstream out_;
    void integer(std::uint32_t n, int bytes) {
        for (int i = 0; i < bytes; i++)
            out_.put(char(n >> (8 * i)));
    }

public:
    Wav(const std::string &path, int frames) : out_(path, std::ios::binary) {
        if (!out_)
            throw std::runtime_error("cannot open WAV: " + path);
        out_.write("RIFF", 4);
        integer(36 + frames * 4, 4);
        out_.write("WAVEfmt ", 8);
        integer(16, 4);
        integer(1, 2);
        integer(2, 2);
        integer(44100, 4);
        integer(44100 * 4, 4);
        integer(4, 2);
        integer(16, 2);
        out_.write("data", 4);
        integer(frames * 4, 4);
    }
    void sample(AudioFrame f) {
        for (float x : {f.left, f.right}) {
            const auto v = static_cast<std::int16_t>(std::lround(std::clamp(x, -1.f, 1.f) * 32767));
            integer(static_cast<std::uint16_t>(v), 2);
        }
    }
};
struct Metrics {
    double sum{}, peak{}, delta{};
    std::uint64_t samples{}, clips{};
    AudioFrame previous{};
    void add(AudioFrame f) {
        for (float x : {f.left, f.right}) {
            if (!std::isfinite(x))
                throw std::runtime_error("nonfinite capture");
            sum += x * x;
            peak = std::max(peak, double(std::abs(x)));
            clips += std::abs(x) > 1;
            ++samples;
        }
        delta = std::max(
            {delta, double(std::abs(f.left - previous.left)), double(std::abs(f.right - previous.right))});
        previous = f;
    }
    void print(const char *name) const {
        std::cout << name << " peak=" << peak << " rms=" << std::sqrt(sum / samples)
                  << " max_sample_delta=" << delta << " clipping_samples=" << clips << '\n';
    }
};
template <class Scenario>
void capture(const std::string &prefix, int frames, float pedal, OutdoorScene scene, TwoStrokeConfig config) {
    std::unique_ptr<Scenario> s;
    if constexpr (std::is_same_v<Scenario, TwoStrokeScenario>) s = std::make_unique<Scenario>(44100, config);
    else s = std::make_unique<Scenario>();
    s->throttle = pedal;
    s->set_audio_scene(scene);
    Wav rendered(prefix + "-rendered.wav", frames), dry(prefix + "-dry.wav", frames),
        raw(prefix + "-unfiltered.wav", frames);
    Metrics m, d, r;
    int cuts = 0;
    for (int i = 0; i < frames; i++) {
        auto f = s->process(), df = s->dry_audio(), rf = s->unfiltered_audio();
        m.add(f);
        d.add(df);
        r.add(rf);
        rendered.sample(f);
        dry.sample(df);
        raw.sample(rf);
        if (i % 4410 == 0)
            cuts += s->snapshot().fuel_cut;
    }
    m.print("rendered");
    d.print("dry filtered");
    r.print("unfiltered spatial");
    std::cout << "fuel-cut checkpoints=" << cuts << " final_rpm=" << s->snapshot().rpm
              << " scene=" << scene_name(scene) << '\n';
}
} // namespace
int main(int argc, char **argv) {
    try {
        std::string scenario = "twin", prefix = "build/audio/twin", scene = "wall";
        float seconds = 6, pedal = 1;
        TwoStrokeConfig config;
        bool turbo_enabled = false;
        std::string turbo_name;
        for (int i = 1; i < argc; i++) {
            std::string key = argv[i];
            if (i + 1 >= argc)
                throw std::runtime_error("missing option value");
            std::string value = argv[++i];
            if (key == "--scenario")
                scenario = value;
            else if (key == "--out")
                prefix = value;
            else if (key == "--seconds")
                seconds = std::stof(value);
            else if (key == "--throttle")
                pedal = std::stof(value);
            else if (key == "--turbo") {
                if (value != "none" && value != "vz21" && value != "gt17") throw std::runtime_error("choose none, vz21 or gt17 turbo");
                turbo_name = value;
                turbo_enabled = value != "none";
            }
            else if (key == "--exhaust") {
                if (value == "racing") config.exhaust = TwoStrokeExhaust::Racing;
                else if (value == "straight") config.exhaust = TwoStrokeExhaust::Straight;
                else throw std::runtime_error("choose racing or straight exhaust");
            }
            else if (key == "--scene")
                scene = value;
            else
                throw std::runtime_error("unknown capture option");
        }
        if (!std::isfinite(seconds) || seconds <= 0 || seconds > 600 || !std::isfinite(pedal) || pedal < 0 ||
            pedal > 1)
            throw std::runtime_error("invalid capture duration or throttle");
        OutdoorScene selected;
        if (scene == "dry")
            selected = OutdoorScene::Dry;
        else if (scene == "field")
            selected = OutdoorScene::Field;
        else if (scene == "wall")
            selected = OutdoorScene::Wall;
        else if (scene == "woodland")
            selected = OutdoorScene::Woodland;
        else
            throw std::runtime_error("invalid scene");
        if (!std::filesystem::path(prefix).parent_path().empty())
            std::filesystem::create_directories(std::filesystem::path(prefix).parent_path());
        const int frames = int(std::lround(seconds * 44100));
        if (turbo_name.empty() && scenario == "b205") turbo_enabled = true;
        if (!turbo_name.empty() && turbo_name!="none" &&
            !((turbo_name=="vz21" && scenario=="twin") || (turbo_name=="gt17" && scenario=="b205")))
            throw std::runtime_error("use gt17 with b205 or vz21 with twin");
        if (scenario == "twin" && turbo_enabled)
            capture<TurboTwinScenario>(prefix, frames, pedal, selected, config);
        else if (scenario == "twin")
            capture<FourStrokeTwinScenario>(prefix, frames, pedal, selected, config);
        else if (scenario == "b205" && turbo_enabled)
            capture<SaabTurboScenario>(prefix, frames, pedal, selected, config);
        else if (scenario == "b205")
            capture<SaabB205Scenario>(prefix, frames, pedal, selected, config);
        else if (scenario == "two-stroke")
            capture<TwoStrokeScenario>(prefix, frames, pedal, selected, config);
        else if (scenario == "v8")
            capture<AmericanV8Scenario>(prefix, frames, pedal, selected, config);
        else
            throw std::runtime_error("choose twin, two-stroke, b205 or v8");
    } catch (const std::exception &e) {
        std::cerr << e.what() << '\n';
        return 1;
    }
}