selcal/src/synth.cpp

#include "synth.h"

#include <stdexcept>
#include <sstream>
#include <log4cxx/logger.h>

namespace {
// Helpers for the C API stuff
constexpr int TRUE = 1;
constexpr int FALSE = 0;

static auto logger = log4cxx::Logger::getLogger("synth");
static auto fluidLogger = log4cxx::Logger::getLogger("synth.fluid");
}


Synth::Synth() {
    try {
        settings = new_fluid_settings();
        if (settings == nullptr) {
            throw new std::runtime_error("Unable to create fluid settings");
        }

        synth = new_fluid_synth(settings);
        if (synth == nullptr) {
            throw new std::runtime_error("Unable to create fluid synth");
        }

#ifdef OUPUT_TO_FILE
        fluid_settings_setstr(settings, "audio.driver", "file");
        fluid_settings_setstr(settings, "audio.file.name", "output.raw");
        fluid_settings_setstr(settings, "audio.file.format", "s16");
        fluid_settings_setstr(settings, "audio.file.type", "raw");
#endif

        fluid_settings_setnum(settings, "synth.sample-rate", 44100);
        fluid_settings_setnum(settings, "synth.gain", 1.0);

        adriver = new_fluid_audio_driver(settings, synth);
        if (adriver == nullptr) {
            throw new std::runtime_error("Unable to create audio driver");
        }
    }
    catch (std::runtime_error& e) {
        // Do a mem-safe cleanup and rethrow.
        // TODO JMT: Do these handle receiving nullptr for deletes?
        delete_fluid_audio_driver(adriver);
        delete_fluid_synth(synth);
        delete_fluid_settings(settings);
        throw;
    }
}

Synth::~Synth() {
    // TODO JMT: Do I need to manually clear all of the soundfonts and programs I have handles for?
    delete_fluid_audio_driver(adriver);
    delete_fluid_synth(synth);
    delete_fluid_settings(settings);
}

bool Synth::loadSoundfont(const std::string& filepath) {
    int soundfontId = fluid_synth_sfload(synth, filepath.c_str(), 1);
    if(soundfontId == FLUID_FAILED) {
        return false;
    }

    fluid_sfont_t* soundfontHandle = fluid_synth_get_sfont_by_id(synth, soundfontId);
    const std::string soundfontName{fluid_sfont_get_name(soundfontHandle)};

    Synth::Soundfont soundfont{soundfontName, soundfontId};
    soundfonts.push_back(soundfont);

    fluid_preset_t* preset = nullptr;
    fluid_sfont_iteration_start(soundfontHandle);
    while ((preset = fluid_sfont_iteration_next(soundfontHandle)) != nullptr) {
        const std::string presetName{fluid_preset_get_name(preset)};
        const int bankNumber = fluid_preset_get_banknum(preset);
        const int programNumber = fluid_preset_get_num(preset);

        Synth::Program program {presetName, soundfontId, bankNumber, programNumber};
        programs.push_back(program);
    }

    return true;
}

bool Synth::loadProgram(const Program& program) {
    // TODO JMT: fix this
    fluid_synth_program_select(synth, 0, program.soundfontId, program.bankNumber, program.programNumber);
    fluid_synth_program_select(synth, 1, program.soundfontId, program.bankNumber, program.programNumber);
    return true;
}

bool Synth::setTuning(const TuningFrequencies& frequencies) {
    // fluidsynth wants tunings in MIDI cents, which effectively means MIDI key * 100.
    // For example: normally note 0 is 0.0, 1 is 100.0, 60 is 6000.0, etc.
    constexpr double MIDI_CENT_SCALE = 100.0;
    std::array<double, NUM_MIDI_KEYS> pitchCents;
    std::transform(
        frequencies.begin(),
        frequencies.end(),
        pitchCents.begin(),
        [] (double frequency) {
            // Remap 0 Hz to MIDI 0, otherwise we get -inf which causes some interpolations between
            // notes to result in zero sound.
            return frequency == 0.0 ? 0.0 : frequencyToMidiKey(frequency) * MIDI_CENT_SCALE;
        }
    );

    std::stringstream ss;
    for (auto p : pitchCents) {
        ss << p << ", ";
    }
    LOG4CXX_DEBUG(logger, "Tuning pitches [" << ss.str() << "]");

    auto result = fluid_synth_activate_key_tuning(synth, 0, 0, "default", pitchCents.data(), FALSE);
    return (result == FLUID_OK) ? activateTuning() : false;
}

bool Synth::resetTuning() {
    auto result = fluid_synth_activate_key_tuning(synth, 0, 0, "default", nullptr, 1);
    return (result == FLUID_OK) ? activateTuning() : false;
}

const std::vector<Synth::Program>& Synth::getPrograms() const {
    return programs;
}

fluid_synth_t* Synth::getSynth() {
    return synth;
}


bool Synth::activateTuning() {
    int channelIndex = 0;
    int result;

    do {
        result = fluid_synth_activate_tuning(synth, channelIndex++, 0, 0, TRUE);
    } while (result == FLUID_OK && channelIndex < NUM_MIDI_CHANNELS);

    LOG4CXX_DEBUG(logger, "Tuning activation result: " << result);

    return result == FLUID_OK;
}

// Fluid logging redirector.
void fluid_log_function(int level, const char* message, void* data) {
    switch (level) {
        case FLUID_PANIC:
            LOG4CXX_FATAL(fluidLogger, message);
            break;
        case FLUID_ERR:
            LOG4CXX_ERROR(fluidLogger, message);
            break;
        case FLUID_WARN:
            LOG4CXX_WARN(fluidLogger, message);
            break;
        case FLUID_INFO:
            LOG4CXX_INFO(fluidLogger, message);
            break;
        case FLUID_DBG:
            LOG4CXX_DEBUG(fluidLogger, message);
            break;
    }
}

void redirect_fluid_logs() {
    fluid_set_log_function(FLUID_PANIC, fluid_log_function, NULL);
    fluid_set_log_function(FLUID_ERR, fluid_log_function, NULL);
    fluid_set_log_function(FLUID_WARN, fluid_log_function, NULL);
    fluid_set_log_function(FLUID_INFO, fluid_log_function, NULL);
    fluid_set_log_function(FLUID_DBG, fluid_log_function, NULL);
}