Better polyphony handling

CMakeLists.txt

@@ -22,7 +22,7 @@ add_executable(main
     src/synthframe.cpp
     src/synth/synth.cpp
     src/synth/voicemanager.cpp
-    src/synth/part.cpp
+    src/synth/channel.cpp
     src/synth/preset.cpp
     src/synth/voice.cpp
     src/synth/dsp/oscillator.cpp

include/synth/channel.h

@@ -9,13 +9,13 @@
 #include "voice.h"
 #include "preset.h"
 
-class Part {
+class Channel {
 public:
+    channel_t number;
     VoiceManager* voiceManager;
-
     Voice::Settings settings;
 
-    Part() : volume(1), pitchBend(0), modulation(0), lfoPhase(randPhase()) {}
+    Channel() : volume(1), pitchBend(0), modulation(0), lfoPhase(randPhase()) {}
 
     void loadPreset(const Preset* preset);
 
@@ -25,11 +25,9 @@ public:
 
     frame tick() {
         frame out{0};
-        for(auto& kv : notes) {
-            int note = kv.first;
-            for(auto& voice : kv.second) {
-                out += voice->tick(note + pitchBend + settings.lfoPitchMod * sin(lfoPhase));
-            }
+        Voice** voices = voiceManager->getChannelVoices(number);
+        for(Voice** voice = voices; *voice != NULL; ++voice) {
+            out += (*voice)->tick(pitchBend + settings.lfoPitchMod * sin(lfoPhase));
         }
         out *= volume;
 
@@ -47,8 +45,6 @@ private:
     float modulation;
 
     float lfoPhase;
-
-    std::unordered_map<uint8_t, std::set<Voice*>> notes;
 };
 
 #endif

include/synth/dsp/adsr.h

@@ -17,6 +17,7 @@ public:
     Envelope const * env;
 
     ADSR() : state(IDLE), t(0), last(0) {};
+    void reset();
     void assign(Envelope const * env);
     void noteOn();
     void noteOff();

include/synth/synth.h

@@ -2,14 +2,15 @@
 #define __SYNTH_H__
 
 #include "voicemanager.h"
-#include "part.h"
+#include "channel.h"
 
 class Synth {
 public:
     Synth() {
         for(int i = 0; i < 16; ++i) {
-            parts[i].voiceManager = &voiceManager;
-            parts[i].loadPreset(&DEFAULT_PRESET);
+            channels[i].number = i;
+            channels[i].voiceManager = &voiceManager;
+            channels[i].loadPreset(&DEFAULT_PRESET);
         }
     }
     
@@ -19,8 +20,8 @@ public:
     
     frame tick() {
         frame out{};
-        for(auto& part : parts) {
-            out += part.tick();
+        for(auto& channel : channels) {
+            out += channel.tick();
         }
         out *= 0.100;
         return out;
@@ -28,7 +29,7 @@ public:
 
 private:
     VoiceManager voiceManager{};
-    Part parts[16];
+    Channel channels[16];
 };
 
 #endif

include/synth/voice.h

@@ -39,18 +39,18 @@ private:
     Filter filter;
 
 public:
-    bool keyed;
+    int note;
 
-    Voice(): keyed(false) {}
+    void reset();
     void assign(Settings const * settings);
-    void noteOn();
+    void noteOn(int note);
     void noteOff();
-    bool isIdle() { return adsrAmp.isIdle(); }
+    inline bool isIdle() { return adsrAmp.isIdle(); }
 
-    inline float tick(float note) {
-        const float keyTrackMul = 1 + settings->keyTrack * noteToFreq(note) / 440.0;
-        const float osc1PhaseStep = noteToFreq(note - settings->oscDetune) * PIx2 / SAMPLE_RATE;
-        const float osc2PhaseStep = noteToFreq(note + settings->oscDetune + settings->osc2Pitch) * PIx2 / SAMPLE_RATE;
+    inline float tick(float pitchMod) {
+        const float keyTrackMul = 1 + settings->keyTrack * noteToFreq(note + pitchMod) / 440.0;
+        const float osc1PhaseStep = noteToFreq(note + pitchMod - settings->oscDetune) * PIx2 / SAMPLE_RATE;
+        const float osc2PhaseStep = noteToFreq(note + pitchMod + settings->oscDetune + settings->osc2Pitch) * PIx2 / SAMPLE_RATE;
         float out = 0;
         out += (1 - settings->oscMix) * osc1.tick(osc1PhaseStep);
         out +=      settings->oscMix  * osc2.tick(osc2PhaseStep);

include/synth/voicemanager.h

@@ -5,17 +5,26 @@
 
 #include "synth/voice.h"
 
+#define NUM_VOICES 16
+
+typedef unsigned int channel_t;
+typedef unsigned int serial_t;
+
 class VoiceManager {
 public:
     VoiceManager();
-    Voice * allocate();
-    void free(Voice * voice);
-    
+    Voice* get(channel_t channel);
+    Voice** getChannelVoices(channel_t channel);
 
 private:
-    Voice voices[64];
-    std::unordered_set<size_t> idle;
-    std::unordered_set<size_t> active;
+    struct VoiceData {
+        channel_t channel;
+        serial_t serial;
+        Voice voice;
+    };
+
+    unsigned int serial;
+    VoiceData voices[NUM_VOICES];
 };
 
 #endif

src/synth/channel.cpp

@@ -3,7 +3,7 @@
 #include "synth/globals.h"
 #include "synth/cc.h"
 
-#include "synth/part.h"
+#include "synth/channel.h"
 
 float timeToStep(float t) {
     return (1.0 / SAMPLE_RATE) / t;
@@ -25,7 +25,7 @@ float ccToLFOPitchMod(int x) {
     return 0.01 * exp(x * 7.090076835776092 / 127.0);
 }
 
-void Part::loadPreset(const Preset * preset) {
+void Channel::loadPreset(const Preset * preset) {
     settings.osc1Mode = Oscillator::Mode(preset->osc1Mode);
     settings.osc2Mode = Oscillator::Mode(preset->osc2Mode);
     settings.oscMix = preset->oscMix / 127.0;
@@ -54,42 +54,22 @@ void Part::loadPreset(const Preset * preset) {
     settings.lfoFltMod = preset->lfoFltMod / 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();
+void Channel::noteOn(int note, int velocity) {
+    Voice* const voice = voiceManager->get(number);
     voice->assign(&settings);
-    voice->noteOn();
-    if(notes.count(note)) {
-        notes.at(note).insert(voice);
-    } else {
-        notes.emplace(note, std::set<Voice *>{voice});
-    }
+    voice->noteOn(note);
 }
 
-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 Channel::noteOff(int note) {
+    Voice** voices = voiceManager->getChannelVoices(number);
+    for(Voice** voice = voices; *voice != NULL; ++voice) {
+        if((*voice)->note == note) {
+            (*voice)->noteOff();
+        }        
     }
 }
 
-void Part::control(int code, int value) {
+void Channel::control(int code, int value) {
     switch(code) {
         case CC_VOLUME: // Volume (Standard MIDI)
             volume = value / 127.0;

src/synth/dsp/adsr.cpp

@@ -1,5 +1,10 @@
 #include "synth/dsp/adsr.h"
 
+void ADSR::reset() {
+    state = IDLE;
+    t = 0;
+}
+
 void ADSR::assign(Envelope const * env) {
     this->env = env;
 }
@@ -10,6 +15,8 @@ void ADSR::noteOn() {
 }
 
 void ADSR::noteOff() {
-    state = RELEASE;
-    t = 1;
+    if(state != RELEASE) {
+        state = RELEASE;
+        t = 1;
+    }
 }

src/synth/synth.cpp

@@ -3,16 +3,16 @@
 #include "synth/synth.h"
 
 void Synth::noteOn(int ch, int note, int vel) {
-    parts[ch].noteOn(note, vel);
+    channels[ch].noteOn(note, vel);
     std::cout << "Note On: ch=" << ch << " note=" << note << " vel=" << vel << std::endl;
 }
 
 void Synth::noteOff(int ch, int note) {
-    parts[ch].noteOff(note);
+    channels[ch].noteOff(note);
     std::cout << "Note Off: ch=" << ch << " note=" << note << std::endl;
 }
 
 void Synth::control(int ch, int cc, int val) {
-    parts[ch].control(cc, val);
+    channels[ch].control(cc, val);
     std::cout << "Controller: ch=" << ch << " cc=" << cc << " val=" << val << std::endl;
 }

src/synth/voice.cpp

@@ -1,5 +1,10 @@
 #include "synth/voice.h"
 
+void Voice::reset() {
+    adsrAmp.reset();
+    adsrMod.reset();
+}
+
 void Voice::assign(Settings const * settings) {
     this->settings = settings;
     adsrAmp.assign(&settings->ampEnv);
@@ -9,14 +14,13 @@ void Voice::assign(Settings const * settings) {
     filter.assign(&settings->filter);
 }
 
-void Voice::noteOn() {
-    keyed = true;
+void Voice::noteOn(int note) {
+    this->note = note;
     adsrAmp.noteOn();
     adsrMod.noteOn();
 }
 
 void Voice::noteOff() {
-    keyed = false;
     adsrAmp.noteOff();
     adsrMod.noteOff();
 }

src/synth/voicemanager.cpp

@@ -2,23 +2,40 @@
 
 #include "synth/voicemanager.h"
 
-VoiceManager::VoiceManager() {
-    for(int i = 0; i < 64; ++i) {
-        idle.insert(i);
+VoiceManager::VoiceManager() : serial(0) {
+    for(VoiceData& vd : voices) {
+        vd.channel = 0;
+        vd.serial = 0;
     }
 }
 
-Voice * VoiceManager::allocate() {
-    int index = *idle.begin();
-    idle.erase(index);
-    active.insert(index);
-    std::cout << "allocate(): active=" << active.size() << " idle=" << idle.size() << std::endl;
-    return &voices[index];
+Voice * VoiceManager::get(channel_t channel) {
+    // Sort idle voices first, then by highest channel and lowest serial
+    std::sort(std::begin(voices), std::end(voices), [](VoiceData& a, VoiceData& b) {
+        return (a.voice.isIdle() && !b.voice.isIdle()) || a.channel > b.channel || a.serial < b.serial;
+    });
+
+    VoiceData& voiceData = voices[0];
+    voiceData.channel = channel;
+    voiceData.serial = serial++;
+    voiceData.voice.reset();
+
+    for(VoiceData& vd : voices) {
+        std::cout << "channel=" << vd.channel << " serial=" << vd.serial << " idle=" << vd.voice.isIdle() << " note=" << vd.voice.note << std::endl;
+    }
+    std::cout << std::endl;
+
+    return &voiceData.voice;
 }
 
-void VoiceManager::free(Voice * voice) {
-    int index = voice - voices;
-    active.erase(index);
-    idle.insert(index);
-    std::cout << "free(): active=" << active.size() << " idle=" << idle.size() << std::endl;
+Voice** VoiceManager::getChannelVoices(channel_t channel) {
+    static Voice* result[NUM_VOICES + 1];
+    Voice** voice = result;
+    for(VoiceData& voiceData : voices) {
+        if(voiceData.channel == channel && !voiceData.voice.isIdle()) {
+            *voice++ = &voiceData.voice;
+        }
+    }
+    *voice = NULL;
+    return result;
 }