polyphony checkpoint

src/main.cpp

@@ -10,6 +10,7 @@
 #include "ConfigService.hpp"
 #include "synth/AudioEngine.hpp"
 #include "synth/KeyboardController.hpp"
+//#include "synth/ScopeBuffer.hpp"
 
 int main(int argc, char* argv[]) {
 
@@ -17,15 +18,16 @@ int main(int argc, char* argv[]) {
     QGuiApplication app(argc, argv);
     QQmlApplicationEngine engine;
 
-    
     // create app objects
     ConfigService config = ConfigService("config/sonobulus.cfg");
     LoggerService logger = LoggerService(&config, "Engine");
     NoteQueue queue = NoteQueue();
+    //ScopeBuffer scope = ScopeBuffer();
     KeyboardController keyboard(&config, &logger, &queue);
+    Synth synth(&config, &logger, nullptr, &queue);
 
     // audio synthesizer doohickey
-    AudioEngine audioEngine = AudioEngine(&config, &logger, &queue);
+    AudioEngine audioEngine = AudioEngine(&config, &logger, &synth);
     audioEngine.start();
 
     // attach backend gui components

src/synth/AudioEngine.cpp

@@ -6,7 +6,7 @@
 #include <numbers>
 #include <string>
 
-AudioEngine::AudioEngine(ConfigService* config, LoggerService* logger, NoteQueue* noteQueue) : config_(config), logger_(logger), noteQueue_(noteQueue) {
+AudioEngine::AudioEngine(ConfigService* config, LoggerService* logger, Synth* synth) : config_(config), logger_(logger), synth_(synth) {
 
     if(audioDevice_.getDeviceCount() < 1) {
         std::cout << "No audio devices found" << std::endl;
@@ -70,29 +70,23 @@ int32_t AudioEngine::audioCallback(void* outputBuffer, void* inputBuffer, uint32
 
 int32_t AudioEngine::process(float* out, size_t nFrames) {
 
-    NoteEvent noteEvent;
-    while(noteQueue_->pop(noteEvent)) {
-        //std::string msg = "[NoteEvent] Type: " + std::to_string(noteEvent.type) +" Velocity: " + std::to_string(noteEvent.velocity) + " Note:" + std::to_string(noteEvent.note);
-        //logger_->log("Audio", LogFlag::Debug, msg);
-        noteOn_ = (noteEvent.type == NoteEventType::NoteOn) ? true : false;
-        freq_ = 440.0f * pow(2.0f, (static_cast<float>(noteEvent.note) - 69.0f) / 12.0f);
-    }
+    synth_->process(out, nFrames);
 
-    const float twoPi = 2.0f*std::numbers::pi_v<float>;
-    float phaseIncrement = twoPi * freq_ / sampleRate_;
+    // const float twoPi = 2.0f*std::numbers::pi_v<float>;
+    // float phaseIncrement = twoPi * freq_ / sampleRate_;
 
-    for(size_t i = 0; i < nFrames; i++) {
+    // for(size_t i = 0; i < nFrames; i++) {
 
-        // simulate a sine wave
-        phase_ += phaseIncrement;
-        if(phase_ > twoPi) {
-            phase_ -= twoPi;
-        }
-        float outSample = std::sin(phase_) / 4.0f * noteOn_;
+    //     // simulate a sine wave
+    //     phase_ += phaseIncrement;
+    //     if(phase_ > twoPi) {
+    //         phase_ -= twoPi;
+    //     }
+    //     float outSample = std::sin(phase_) / 4.0f * noteOn_;
 
-        out[2*i] = outSample;
-        out[2*i+1] = outSample;
-    }
+    //     out[2*i] = outSample;
+    //     out[2*i+1] = outSample;
+    // }
 
     return 0;
 

src/synth/AudioEngine.hpp

@@ -7,6 +7,7 @@
 
 #include "LoggerService.hpp"
 #include "ConfigService.hpp"
+#include "Synth.hpp"
 #include "NoteQueue.hpp"
 
 
@@ -20,7 +21,7 @@ class AudioEngine {
 
 public:
 
-    AudioEngine(ConfigService* config, LoggerService* logger, NoteQueue* noteQueue);
+    AudioEngine(ConfigService* config, LoggerService* logger, Synth* synth);
     ~AudioEngine();
 
     bool start();
@@ -39,12 +40,8 @@ private:
     uint32_t bufferFrames_ = 512;
     uint32_t channels_ = 2;
 
-    float phase_ = 0.0f;
-    float freq_ = 0.0f;
-    bool noteOn_ = false;
-
     LoggerService* logger_;
     ConfigService* config_;
-    NoteQueue* noteQueue_;
+    Synth* synth_;
 
 };

src/synth/Instrument.cpp

@@ -0,0 +1,36 @@
+
+#include "Instrument.hpp"
+
+#include "string"
+
+Instrument::Instrument(ConfigService* config, LoggerService* logger) :
+    config_(config), logger_(logger) {
+
+}
+
+void Instrument::noteOn(float frequency, float velocity) {
+
+    // std::string msg = "NoteOn Frequency = " + std::to_string(frequency);
+    // if(logger_ != nullptr) logger_->log("Instrument", LogFlag::Debug, msg);
+
+    phaseIncrement_ = 2.0f * pi * frequency / sampleRate_;
+
+    active_ = true;
+}
+
+void Instrument::noteOff() {
+    active_ = false;
+}
+
+bool Instrument::isActive() {
+    return active_;
+}
+
+float Instrument::process(bool& scopeTrigger) {
+
+    phase_ += phaseIncrement_;
+    if(phase_ > 2.0f * pi) phase_ -= 2.0f * pi;
+
+    return sin(phase_);
+
+}

src/synth/Instrument.hpp

@@ -1,6 +1,9 @@
 
 #pragma once
 
+#include "ConfigService.hpp"
+#include "LoggerService.hpp"
+
 // an instrument is our state space model. it calculates discrete samples as a function of time, the current states, and the inputs
 // an instrumeent is owned by a voice
 class Instrument {
@@ -8,8 +11,26 @@ class Instrument {
 public:
 
     Instrument() = default;
+    Instrument(ConfigService* config, LoggerService* logger);
     ~Instrument() = default;
 
-private:
+    void noteOn(float frequency, float velocity);
+    void noteOff();
 
-};
+    bool isActive();
+
+    float process(bool& scopeTrigger);
+
+private: 
+
+    float sampleRate_ = 44100.0f;
+    bool active_ = false;
+
+    ConfigService* config_;
+    LoggerService* logger_;
+
+    static constexpr float pi = 3.14159265358979323846f;
+    float phase_ = 0.0f;
+    float phaseIncrement_ = 0.0f;
+
+};

src/synth/NoteQueue.hpp

@@ -7,8 +7,6 @@
 #include <cstdint>
 #include <chrono>
 
-#define SYNTH_NOTE_QUEUE_SIZE 128
-
 enum NoteEventType {
     NoteOn = 0,
     NoteOff
@@ -32,6 +30,8 @@ public:
 
 private:
     
+    static constexpr size_t SYNTH_NOTE_QUEUE_SIZE = 128;
+
     std::array<NoteEvent, SYNTH_NOTE_QUEUE_SIZE> buffer_;
     std::atomic<size_t> head_{ 0 };
     std::atomic<size_t> tail_{ 0 };

src/synth/Synth.cpp

@@ -0,0 +1,87 @@
+
+#include "Synth.hpp"
+
+Synth::Synth(ConfigService* config, LoggerService* logger, ScopeBuffer* scope, NoteQueue* queue) :
+    config_(config), logger_(logger), scope_(scope), noteQueue_(queue) {
+
+    voices_.fill(Voice(config_, logger_));
+
+}
+
+void Synth::handleNoteEvent(const NoteEvent& event) {
+
+    Voice* v = findVoiceByNote(event.note);
+    if(v != nullptr) v->noteOff();
+
+    if(event.type == NoteEventType::NoteOn) {
+
+        v = findFreeVoice();
+        if(v != nullptr) v->noteOn(event.note, event.velocity);
+    }
+    
+}
+
+void Synth::process(float* out, size_t nFrames) {
+
+    NoteEvent noteEvent;
+    while(noteQueue_->pop(noteEvent)) {
+        handleNoteEvent(noteEvent);
+    }
+
+    // size_t lowestVoice = 0;
+    // float lowestFreq = 100000.0f;
+    // for(size_t i = 0; i < voices_.size(); i++) {
+    //     if(!voices_[i].isActive()) continue;
+    //     float currentFreq = voices_[i].frequency();
+    //     if(currentFreq < lowestFreq) {
+    //         lowestVoice = i;
+    //         lowestFreq = currentFreq;
+    //     }
+    // }
+
+    float sampleOut = 0.0f;
+    for(size_t i = 0; i < nFrames; i++) {
+
+        float mix = 0.0f;
+        for(size_t j = 0; j < voices_.size(); j++) {
+            bool temp = false;
+            if(!voices_[j].isActive()) continue;
+            mix += voices_[j].process(temp);
+            // if(j == lowestVoice) triggered = temp;
+        }
+        mix = tanh(mix/4.0f); // prevent clipping
+
+        sampleOut = mix;
+        out[2*i] = sampleOut;
+        out[2*i+1] = sampleOut;
+
+        // if(scope_) scope_->push(sampleOut);
+        // if(triggered && !once) {
+        //     scope_->setTrigger(i);
+        //     once = true;
+        // }
+
+    }
+
+
+}
+
+Voice* Synth::findFreeVoice() {
+
+    for(Voice& v : voices_) {
+        if(!v.isActive()) {
+            return &v;
+        }
+    }
+    return nullptr;
+}
+
+Voice* Synth::findVoiceByNote(uint8_t note) {
+
+    for(Voice& v : voices_) {
+        if(v.isActive() && v.note() == note) {
+            return &v;
+        }
+    }
+    return nullptr;
+}

src/synth/Synth.hpp

@@ -13,10 +13,10 @@ class Synth {
 
 public:
 
-    Synth(ConfigService* config, LoggerService* logger, ScopeBuffer* scope);
-    ~Synth();
+    Synth(ConfigService* config, LoggerService* logger, ScopeBuffer* scope, NoteQueue* queue);
+    ~Synth() = default;
 
-    void process(float* out, size_t nFrames, uint32_t sampleRate);
+    void process(float* out, size_t nFrames);
     void handleNoteEvent(const NoteEvent& event);
 
 private:
@@ -30,6 +30,9 @@ private:
     static constexpr size_t MAX_VOICES = 32;
     std::array<Voice, MAX_VOICES> voices_;
 
+    ConfigService* config_;
+    LoggerService* logger_;
     ScopeBuffer* scope_ = nullptr;
+    NoteQueue* noteQueue_;
 
-}
+};

src/synth/Voice.cpp

@@ -0,0 +1,34 @@
+
+#include "Voice.hpp"
+
+Voice::Voice(ConfigService* config, LoggerService* logger) :
+    config_(config), logger_(logger) {
+
+    instrument_ = Instrument(config_, logger_);
+
+}
+
+void Voice::noteOn(uint8_t midiNote, float velocity) {
+
+    note_ = midiNote;
+    instrument_.noteOn(noteToFrequency(midiNote), velocity);
+
+}
+
+void Voice::noteOff() {
+
+    instrument_.noteOff();
+
+}
+
+bool Voice::isActive() {
+
+    return instrument_.isActive();
+
+}
+
+float Voice::process(bool& scopeTrigger) {
+
+    return instrument_.process(scopeTrigger);
+
+}

src/synth/Voice.hpp

@@ -12,9 +12,10 @@ class Voice {
 public:
 
     Voice() = default;
+    Voice(ConfigService* config, LoggerService* logger);
     ~Voice() = default;
 
-    void noteOn(int8_t midiNote, float velocity);
+    void noteOn(uint8_t midiNote, float velocity);
     void noteOff();
     bool isActive();
 
@@ -25,12 +26,16 @@ private:
 
     float sampleRate_ = 44100.0f;
 
-    inline float noteToFrequency(uint8_t note);
+    inline float noteToFrequency(uint8_t note) {
+        return 440.0f * pow(2.0f, static_cast<float>(note - 69) / static_cast<float>(12)); 
+    }
     
     uint8_t note_ = 0;
     float velocity_ = 1.0f;
     bool active_ = false;
 
-    Instrument* instrument;
+    ConfigService* config_;
+    LoggerService* logger_;
+    Instrument instrument_;
 
 };