synthapp/lib/synth/src/channel.cpp

#include <iostream>

#include "globals.h"
#include "cc.h"

#include "channel.h"

inline int midiToNote(int note) {
    return note - 24;
}

inline float timeToStep(float t) {
    return (float) SAMPLE_RATE_INV / t;
}

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

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

inline float ccToLFOStep(int x) {
    return (float) 0.1f * expf((1 + x) * 6.907755278982137f / 128.0f) * (float) SAMPLE_RATE_INV;
}

inline float ccToLFOPitchMod(int x) {
    return 6.f * x * x / 16129.f;
}

inline float ccToLFOFltMod(int x) {
    return (float) FILTER_CV_MAX * (x - 64) / 126.f;
}

void Channel::loadPreset(const Preset * preset) {
    settings.unison = 1 + floorf(preset->unison * 8.f / 128.f);

    settings.osc1Mode = Oscillator::Mode(preset->osc1Mode);
    settings.osc2Mode = Oscillator::Mode(preset->osc2Mode);
    settings.oscDetune = preset->oscDetune / 254.f;
    settings.osc2Pitch = floorf(preset->osc2Pitch * 13.f / 128.f);
    settings.oscMix = preset->oscMix / 127.f;
    settings.noiseMix = preset->noiseMix / 127.f;

    settings.filter.type = Filter::Type(floorf(3.f * preset->filter.type / 128.f));
    settings.filter.slope = Filter::Slope(floorf(2.f * preset->filter.slope / 128.f));
    settings.filter.freq = (float) FILTER_CV_MAX * preset->filter.freq / 127.f;
    settings.filter.res = preset->filter.Q / 31.75f;

    settings.ampEnv.attackStep = timeToStep(ccToA(preset->ampEnv.attack));
    settings.ampEnv.decayStep = timeToStep(ccToDR(preset->ampEnv.decay));
    settings.ampEnv.sustain = preset->ampEnv.sustain / 127.f;
    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.f;
    settings.modEnv.releaseStep = timeToStep(ccToDR(preset->modEnv.release));

    settings.modEnvFltGain = (float) FILTER_CV_MAX * preset->modEnvFltGain / 127.f;
    settings.keyTrack = preset->keyTrack / 127.f;
    settings.lfoStep = ccToLFOStep(preset->lfoFreq);
    settings.lfoPitchMod = ccToLFOPitchMod(preset->lfoPitchMod);
    settings.lfoFltMod = ccToLFOFltMod(preset->lfoFltMod);

    settings.reverb = preset->reverb / 127.f;
}

void Channel::noteOn(int note, int velocity) {
    //printf("on: midi=%d note=%d\n", note, midiToNote(note));
    Voice* const voice = voiceManager->get(number);
    voice->assign(&settings);
    voice->noteOn(midiToNote(note), velocity / 127.f, 1.f, 0.5f);
}

void Channel::noteOff(int note) {
    Voice** voices = voiceManager->getChannelVoices(number);
    for(Voice** voice = voices; *voice != NULL; ++voice) {
        if((*voice)->note == midiToNote(note)) {
            //printf("off: midi=%d note=%d\n", note, midiToNote(note));
            (*voice)->noteOff();
        }        
    }
}

void Channel::control(int code, int value) {
    switch(code) {
        case CC_VOLUME: // Volume (Standard MIDI)
            volume = value / 127.f;
            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.f;
            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.res = value / 31.75f;
            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 = (float) FILTER_CV_MAX * value / 127.f;
            break;

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

        case CC_AMP_SUS: // Sustain
            settings.ampEnv.sustain = value / 127.f;
            break;

        case CC_OSC_DET: // Detune (Standard MIDI)
            settings.oscDetune = value / 254.f;
            break;

        case CC_OSC2PIT: // Oscillator 2 Pitch
            settings.osc2Pitch = floorf(value * (13.f / 128.f));
            break;

        case CC_MOD_FLT: // Mod Envelope Filter Gain
            settings.modEnvFltGain = (float) FILTER_CV_MAX * value / 127.f;
            break;

        case CC_KEY_TRK: // Filter Key Tracking
            settings.keyTrack = value / 127.f;
            break;

        case CC_LFO_FRQ: // LFO Frequency
            settings.lfoStep = ccToLFOStep(value);
            break;

        case CC_LFO_PIT: // LFO Pitch Modulation
            settings.lfoPitchMod = ccToLFOPitchMod(value);
            break;

        case CC_LFO_FLT: // LFO Filter Modulation
            settings.lfoFltMod = ccToLFOFltMod(value);
            break;

        case CC_UNISON: // Unison Amount
            settings.unison = 1 + floorf(value * 8.f / 128.f);
            break;

        case CC_OSC_MIX: // Oscillator 1/2 Mix
            settings.oscMix = value / 127.f;
            break;

        case CC_OSC1MDE: // Oscillator 1 Mode
            settings.osc1Mode = Oscillator::Mode(floorf(3.f * value / 128.f));
            break;
        
        case CC_OSC2MDE: // Oscillator 2 Mode
            settings.osc2Mode = Oscillator::Mode(floorf(3.f * value / 128.f));
            break;

        case CC_FLT_TYP: // Filter Type
            settings.filter.type = Filter::Type(floorf(3.f * value / 128.f));
            break;

        case CC_FLT_SLP: // Filter Slope
            settings.filter.slope = Filter::Slope(floorf(2.f * value / 128.f));
            break;

        case CC_RVB_SND:
            settings.reverb = value / 127.f;
            break;

        case CC_NOI_MIX:
            settings.noiseMix = value / 127.f;
            break;

        // LFO delay
        // Reverb Time
        // Reverb Brightness
        // Reverb Density
    }
}