raspi-synth/src/synth/part.cpp

#include <iostream>

#include "synth/globals.h"
#include "synth/cc.h"

#include "synth/part.h"

float timeToStep(float t) {
    return (1.0 / SAMPLE_RATE) / t;
}

float ccToA(int x) {
    return 5.0 * exp(9.2 * (x / 127.0) - 9.2);
}

float ccToDR(int x) {
    return 5.0 * exp(7.0 * (x / 127.0) - 7.0);
}

void Part::loadPreset(const Preset * preset) {
    settings.osc1Mode = Oscillator::Mode(preset->osc1Mode);
    settings.osc2Mode = Oscillator::Mode(preset->osc2Mode);
    settings.oscMix = preset->oscMix / 127.0;
    settings.oscDetune = (preset->oscDetune - 64.0) / 100.0;

    settings.filter.type = Filter::Type(preset->filter.type);
    settings.filter.slope = Filter::Slope(preset->filter.slope);
    settings.filter.freq = preset->filter.freq / 127.0;
    settings.filter.Q = preset->filter.Q / 31.75;

    settings.ampEnv.attackStep = timeToStep(ccToA(preset->ampEnv.attack));
    settings.ampEnv.decayStep = timeToStep(ccToDR(preset->ampEnv.decay));
    settings.ampEnv.sustain = preset->ampEnv.sustain / 127.0;
    settings.ampEnv.releaseStep = timeToStep(ccToDR(preset->ampEnv.release));

    settings.modEnv.attackStep = timeToStep(ccToA(preset->modEnv.attack));
    settings.modEnv.decayStep = timeToStep(ccToDR(preset->modEnv.decay));
    settings.modEnv.sustain = preset->modEnv.sustain / 127.0;
    settings.modEnv.releaseStep = timeToStep(ccToDR(preset->modEnv.release));

    settings.modEnvFltGain = preset->modEnvFltGain / 127.0;
    settings.keyTrack = preset->keyTrack / 127.0;
}

void Part::noteOn(int note, int velocity) {
    // Garbage collection - free up idle voices
    std::erase_if(notes, [this](auto& note) {
        std::erase_if(note.second, [this](auto& voice) {
            if(voice->isIdle()) {
                voiceManager->free(voice);
                return true;
            }
            return false;
        });
        return note.second.empty();
    });

    Voice * const voice = voiceManager->allocate();
    voice->assign(&settings);
    voice->noteOn();
    if(notes.count(note)) {
        notes.at(note).insert(voice);
    } else {
        notes.emplace(note, std::set<Voice *>{voice});
    }
}

void Part::noteOff(int note) {
    if(notes.count(note)) {
        auto& voices = notes.at(note);
        for (auto i = voices.rbegin(); i != voices.rend(); ++i ) {
            if((*i)->keyed) {
                (*i)->noteOff();
                break;
            }
        } 
    }
}

void Part::control(int code, int value) {
    switch(code) {
        case CC_VOLUME: // Volume (Standard MIDI)
            volume = value / 127.0;
            break;

        case CC_FLT_ATK: // Filter Attack Time
            settings.modEnv.attackStep = timeToStep(ccToA(value));
            break;
        
        case CC_FLT_DEC: // Filter Decay Time
            settings.modEnv.decayStep = timeToStep(ccToDR(value));
            break;

        case CC_FLT_SUS: // Filter Sustain
            settings.modEnv.sustain = value / 127.0;
            break;

        case CC_FLT_REL: // Filter Release Time
            settings.modEnv.releaseStep = timeToStep(ccToDR(value));
            break;

        case CC_FLT_Q: // Timbre / Harmonic Content (Standard MIDI)
            settings.filter.Q = value / 31.75;
            std::cout << "Q=" << settings.filter.Q << std::endl;
            break;

        case CC_AMP_REL: // Release Time (Standard MIDI)
            settings.ampEnv.releaseStep = timeToStep(ccToDR(value));
            break;

        case CC_AMP_ATK: // Attack Time (Standard MIDI)
            settings.ampEnv.attackStep = timeToStep(ccToA(value));
            break;

        case CC_FLT_FRQ: // Brightness (Standard MIDI)
            settings.filter.freq = value / 127.0;
            break;

        case CC_AMP_DEC: // Decay Time
            settings.ampEnv.decayStep = timeToStep(ccToDR(value));
            break;

        case CC_AMP_SUS: // Sustain
            settings.ampEnv.sustain = value / 127.0;
            break;

        case CC_OSC_DET: // Detune (Standard MIDI)
            settings.oscDetune = (value - 64.0) / 100.0;
            break;

        case CC_MOD_FLT: // Mod Envelope Filter Gain
            settings.modEnvFltGain = value / 127.0;
            break;

        case CC_KEY_TRK: // Filter Key Tracking
            settings.keyTrack = value / 127.0;
            break;
    }
}