Synthesizer.h

#pragma once
 
#include "AudioTools/CoreAudio/AudioLogger.h"
#include "AudioTools/CoreAudio/AudioTypes.h"
#include "AudioTools/CoreAudio/AudioBasic/Collections.h"
#include "AudioTools/CoreAudio/AudioActions.h"
#include "AudioTools/CoreAudio/AudioStreams.h"
#include "SoundGenerator.h"
#include "AudioEffects.h"
#ifdef USE_MIDI
#include "Midi.h"
#endif
 
namespace audio_tools {
 
class AbstractSynthesizerChannel {
    public:
        virtual ~AbstractSynthesizerChannel() = default;
        virtual AbstractSynthesizerChannel* clone() = 0;
        virtual void begin(AudioInfo config);
        virtual bool isActive() = 0;
        virtual void keyOn(int nte, float tgt) = 0;
        virtual void keyOff() = 0;
        virtual int16_t readSample()=0;
        virtual int note() = 0 ;
};
 
class DefaultSynthesizerChannel : public AbstractSynthesizerChannel {
    public:
        DefaultSynthesizerChannel() = default;
 
        DefaultSynthesizerChannel(SoundGenerator<int16_t> &generator){
            setGenerator(generator);
        } 
 
        DefaultSynthesizerChannel(DefaultSynthesizerChannel &ch) = default;
        
        DefaultSynthesizerChannel *clone() override {
            TRACED();
            auto result = new DefaultSynthesizerChannel(*this);
            result->begin(config);
            return result;
        }
 
        void setGenerator(SoundGenerator<int16_t> &generator){
            p_generator = &generator;
        }
 
        virtual void begin(AudioInfo config) override {
            TRACEI();
            this->config = config;
            config.logInfo();
 
            // setup generator
            if (p_generator==nullptr){
                static FastSineGenerator<int16_t> sine;
                p_generator = &sine;
            }
            p_generator->begin(config);
 
            // find ADSRGain
            p_adsr = (ADSRGain*) effects.findEffect(1);
            if (p_adsr==nullptr){
                p_adsr = new ADSRGain(0.0001, 0.0001, 0.8, 0.0005);
                p_adsr->setId(1);
                effects.addEffect(p_adsr);
            } 
        }
 
        virtual bool isActive() override{
            return p_adsr != nullptr ? p_adsr->isActive() : false;
        }
 
        virtual void keyOn(int note, float tgt) override{
            if (p_generator!=nullptr){
                p_generator->setFrequency(note);
            }
            if (p_adsr!=nullptr){
                actual_note = note;
                p_adsr->keyOn(tgt);  
            } 
        }
 
        virtual void keyOff() override{
            TRACED();
            if (p_adsr!=nullptr){
                p_adsr->keyOff();
            } else {
                LOGE("p_adsr is null")
            }
        }
 
        virtual int16_t readSample() override{
            if (p_generator==nullptr) return 0;
            int16_t sample = p_generator->readSample();
            int size = effects.size();
            for (int j=0; j<size; j++){
                sample = effects[j]->process(sample);
            }
            return sample;
        }
 
        virtual int note() override {
            return actual_note;
        }
 
        void addEffect(AudioEffect *ptr){
            effects.addEffect(ptr);
        }
 
    protected:
        AudioInfo config;
        AudioEffectCommon effects;
        SoundGenerator<int16_t> *p_generator = nullptr;
        ADSRGain *p_adsr = nullptr;
        int actual_note = 0;
 
};
 
 
struct SynthesizerKey {
    int pin;
    float note;
};
 
class Synthesizer : public SoundGenerator<int16_t> {
    public:
        Synthesizer() {
            defaultChannel = new DefaultSynthesizerChannel();
        }
 
        Synthesizer(AbstractSynthesizerChannel *ch){
            defaultChannel = ch;
        }
        
        Synthesizer(Synthesizer const&) = delete;
        Synthesizer& operator=(Synthesizer const&) = delete;
 
        virtual ~Synthesizer(){
            TRACED();
            for (int j=0;j<channels.size();j++){
                delete channels[j];
                channels[j] = nullptr;
            }
 
#ifdef USE_MIDI
            delete p_synth_action;
#endif
       }
 
        bool begin(AudioInfo config) {
            TRACEI();
            this->cfg = config;
            SoundGenerator<int16_t>::begin(config);
            // provide config to defaut
            defaultChannel->begin(config);
            return true;
        }
 
        void keyOn(int note, float tgt=0){
            LOGI("keyOn: %d", note);
            AbstractSynthesizerChannel *channel = getFreeChannel();
            if (channel!=nullptr){
                channel->keyOn(note, tgt);
            } else {
                LOGW("No channel available for %d",note);
            }
        }
 
        void keyOff(int note){
            LOGI("keyOff: %d", note);
            AbstractSynthesizerChannel *channel = getNoteChannel(note);
            if (channel!=nullptr){
                channel->keyOff();
            }
        }
 
        int16_t readSample() override {
            int total = 0;
            uint16_t count = 0;
            // calculate sum of all channels
            for (int j=0;j<channels.size();j++){
                if (channels[j]->isActive()){
                    count++;
                    total += channels[j]->readSample();
                }
            }
            // prevent divide by zero
            int result = 0;
            if (count>0){
                result = NumberConverter::clipT<int16_t>(total / count);
            }
            return result;
        }
 
        void setKeys(AudioActions &actions, SynthesizerKey* p_keys, AudioActions::ActiveLogic activeValue){
            while (p_keys->note > 0){
                actions.add(p_keys->pin, callbackKeyOn, callbackKeyOff, activeValue , new KeyParameter(this, p_keys->note)); 
                p_keys++;
            }
        }
 
        void setMidiName(const char* name){
            midi_name = name;
        }
 
    protected:
        AudioInfo cfg;
        AbstractSynthesizerChannel* defaultChannel;
        Vector<AbstractSynthesizerChannel*> channels;
        const char* midi_name = "Synthesizer";
 
        struct KeyParameter {
            KeyParameter(Synthesizer* synth, int nte){
                p_synthesizer=synth;
                note = nte;
            };
            Synthesizer *p_synthesizer = nullptr;
            int note;
        };
 
#ifdef USE_MIDI
 
        class SynthAction : public MidiAction {
            private:
                Synthesizer *synth=nullptr;
            public:
                SynthAction(Synthesizer *synth){
                    this->synth = synth;
                }
                void onNoteOn(uint8_t channel, uint8_t note, uint8_t velocity) {
                    int frq = MidiCommon::noteToFrequency(note);
                    float vel = 1.0/127.0 * velocity;
                    synth->keyOn(frq, vel);
                }
                void onNoteOff(uint8_t channel, uint8_t note, uint8_t velocity) {
                    int frq = MidiCommon::noteToFrequency(note);
                    synth->keyOff(frq);
                }
                void onControlChange(uint8_t channel, uint8_t controller, uint8_t value) {}
                void onPitchBend(uint8_t channel, uint8_t value) {}
        };
 
        SynthAction *p_synth_action = new SynthAction(this);
        // Midi BLE Server
        MidiBleServer ble = MidiBleServer(midi_name, p_synth_action);
 
#endif
 
        // gets the channel for the indicated note
        AbstractSynthesizerChannel *getNoteChannel(int note){
            LOGI("getNoteChannel: %d", note);
            for (int j=0;j<channels.size();j++){
                if (channels[j]->note() == note){
                    return channels[j];
                }
            }
            return nullptr;
        }
 
        // gets a free channel
        AbstractSynthesizerChannel *getFreeChannel(){
            LOGI("getFreeChannel");
            for (int j=0;j<channels.size();j++){
                if (!channels[j]->isActive()){
                    return channels[j];
                }
            }
            LOGI("No free channel found: Adding new channel");
            AbstractSynthesizerChannel* ch = defaultChannel->clone();
            channels.push_back(ch);
            return ch;
        }
 
        static void callbackKeyOn(bool active, int pin, void* ref){
            TRACEI();
            KeyParameter* par = (KeyParameter*)ref;
            if (par !=nullptr && par->p_synthesizer!=nullptr){
                par->p_synthesizer->keyOn(par->note);
            } else {
                LOGE("callbackKeyOn: unexpected null")
            }
        }
 
        static void callbackKeyOff(bool active, int pin, void* ref){
            TRACEI();
            KeyParameter* par = (KeyParameter*)ref;
            if (par !=nullptr){
                if (par->p_synthesizer!=nullptr){
                    par->p_synthesizer->keyOff(par->note);
                } else {
                    LOGE("callbackKeyOff: p_synthesizer is null");               
                }
            } else {
                LOGE("callbackKeyOff: ref is null");               
            }
        }
};
 
} // namespace