add visual scope

src/main.cpp

@@ -24,18 +24,17 @@ int main(int argc, char* argv[]) {
     NoteQueue queue = NoteQueue();
     ScopeBuffer scopeBuffer = ScopeBuffer(512);
     KeyboardController keyboard(&config, &logger, &queue);
-    Synth synth(&config, &logger, nullptr, &queue);
+    Synth synth(&config, &logger, &scopeBuffer, &queue);
 
     // audio synthesizer doohickey
     AudioEngine audioEngine = AudioEngine(&config, &logger, &synth);
     audioEngine.start();
 
     // attach backend gui components
-    //Scope scope; //scope.setBuffer(&scopeBuffer);
     qmlRegisterType<TimerComponent>("AppDemo", 1, 0, "TimerComponent");
-    //qmlRegisterSingletonInstance("AppDemo", 1, 0, "Scope", &scope);
     qmlRegisterType<Scope>("AppDemo", 1, 0, "Scope");
     engine.rootContext()->setContextProperty("keyboardController", &keyboard);
+    engine.rootContext()->setContextProperty("scopeBuffer", &scopeBuffer);
 
     // load qml
     //engine.loadFromModule("sonobulus", "Main");

src/synth/Instrument.cpp

@@ -31,7 +31,10 @@ float Instrument::process(bool& scopeTrigger) {
     if(!active_ && envelope_ > 0.0f) envelope_ -= 0.01f;
 
     phase_ += phaseIncrement_;
-    if(phase_ > 2.0f * pi) phase_ -= 2.0f * pi;
+    if(phase_ > 2.0f * pi) {
+        phase_ -= 2.0f * pi;
+        scopeTrigger = true;
+    }
 
     if(!isActive()) return 0.0f;
     return sin(phase_) * envelope_;

src/synth/Scope.cpp

@@ -3,6 +3,10 @@
 
 #include <iostream>
 
+ScopeBuffer::ScopeBuffer(QObject *parent) : QObject(parent) {
+
+}
+
 ScopeBuffer::ScopeBuffer(size_t size) : buffer_(size) {
 
 }
@@ -27,21 +31,45 @@ Scope::Scope(QQuickItem *parent) : QQuickPaintedItem(parent) {
     setAntialiasing(true); 
 }
 
+void Scope::setBuffer(ScopeBuffer* scopeBuffer) {
+    scopeBuffer_ = scopeBuffer;
+    buffer_ = std::vector<float>(scopeBuffer_->size());
+}
+
 void Scope::paint(QPainter *painter) {
 
-    //std::cout << "onPaint" << std::endl;
+    while(scopeBuffer_->spinlock()) {
+        // wait
+    }
 
-    static float phase = 0.0f;
-    phase += 0.1f;
-    float sample = sin(phase);
+    if(scopeBuffer_ != nullptr) scopeBuffer_->read(buffer_);
 
-    QPen pen(Qt::blue, 4);
+    // TODO: scale to max amplitude ?
+    float maxAmp = 1.0f;
+    /*
+    for(float s : buffer_) {
+        maxAmp = std::max(maxAmp, std::abs(s));
+    }
+    */
+
+    float scaleY = (height() * 0.45f) / maxAmp;
+    float midY = height() / 2.0f;
+
+    painter->fillRect(0, 0, width(), height(), QColor(20, 20, 20));
+
+    QPen pen;
+    pen.setWidthF(3.0f);
+    QColor green(50, 255, 70);
+    pen.setColor(green);
     painter->setPen(pen);
     painter->setRenderHint(QPainter::Antialiasing);
 
-    painter->drawRect(10, 10, width() - 20*sample, height() - 20*sample);
-    
-    painter->setPen(QPen(Qt::red, 2));
-    painter->drawLine(0, 0, width(), height());
-
+    for(size_t i = 1; i < buffer_.size(); i++) {
+        painter->drawLine(
+            i * width() / buffer_.size(),
+            midY + buffer_[i-1] * scaleY,
+            i * width() / buffer_.size(),
+            midY + buffer_[i] * scaleY
+        );
+    }
 }

src/synth/Scope.hpp

@@ -8,10 +8,13 @@
 #include <vector>
 #include <atomic>
 
-class ScopeBuffer {
+class ScopeBuffer : public QObject  {
+
+    Q_OBJECT // needed to attach to a qml component
 
 public:
 
+    explicit ScopeBuffer(QObject* parent = nullptr);
     ScopeBuffer(size_t size);
     ~ScopeBuffer() = default;
 
@@ -22,7 +25,8 @@ public:
     void setWavelength(size_t wavelength) { wavelength_ = wavelength; } 
     size_t trigger() { return trigger_; }
     size_t wavelength() { return wavelength_; }
-    void spinlock(bool lock) { spinlock_ = lock; }
+    void spinlock(bool lock) { spinlock_.store(lock, std::memory_order_relaxed); }
+    bool spinlock() { return spinlock_.load(std::memory_order_relaxed); }
     size_t size() { return buffer_.size(); }
 
 private:
@@ -33,20 +37,21 @@ private:
     size_t trigger_ = 0;
     size_t wavelength_ = 400;
 
-    bool spinlock_ = false;
+    std::atomic<bool> spinlock_ = false;
 
 };
 
 class Scope : public QQuickPaintedItem {
 
     Q_OBJECT
-    QML_ELEMENT
+    Q_PROPERTY(ScopeBuffer* buffer WRITE setBuffer)
 
 public:
     explicit Scope(QQuickItem* parent = nullptr);
 
     void paint(QPainter* painter) override;
-    void setBuffer(ScopeBuffer* scopeBuffer) { scopeBuffer_ = scopeBuffer; }
+
+    void setBuffer(ScopeBuffer* scopeBuffer);
 
     std::vector<float> buffer_;
     ScopeBuffer* scopeBuffer_;

src/synth/Synth.cpp

@@ -28,18 +28,22 @@ void Synth::process(float* out, size_t nFrames) {
         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;
-    //     }
-    // }
+    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;
+        }
+    }
+
+    scope_->spinlock(true);
 
     float sampleOut = 0.0f;
+    bool triggered = false;
+    bool once = false;
     for(size_t i = 0; i < nFrames; i++) {
 
         float mix = 0.0f;
@@ -47,7 +51,7 @@ void Synth::process(float* out, size_t nFrames) {
             bool temp = false;
             //if(!voices_[j].isActive()) continue;
             mix += voices_[j].process(temp);
-            // if(j == lowestVoice) triggered = temp;
+            if(j == lowestVoice) triggered = temp;
         }
         mix = tanh(mix/4.0f); // prevent clipping
 
@@ -55,13 +59,14 @@ void Synth::process(float* out, size_t nFrames) {
         out[2*i] = sampleOut;
         out[2*i+1] = sampleOut;
 
-        // if(scope_) scope_->push(sampleOut);
-        // if(triggered && !once) {
-        //     scope_->setTrigger(i);
-        //     once = true;
-        // }
-
+        if(scope_) scope_->push(sampleOut);
+        if(triggered && !once) {
+            scope_->setTrigger(i);
+            once = true;
         }
+    }
+
+    scope_->spinlock(false);
 
 
 }

src/synth/Synth.hpp

@@ -32,7 +32,7 @@ private:
 
     ConfigService* config_;
     LoggerService* logger_;
-    ScopeBuffer* scope_ = nullptr;
+    ScopeBuffer* scope_;;
     NoteQueue* noteQueue_;
 
 };

src/synth/Voice.hpp

@@ -21,6 +21,7 @@ public:
 
     float process(bool& scopeTrigger);
     uint8_t note() { return note_; }
+    float frequency() { return noteToFrequency(note_); }
 
 private:
 

ui/Main.qml

@@ -63,6 +63,8 @@ ApplicationWindow {
             repeat: true
             onTriggered: scope.update()
         }
+
+        buffer: scopeBuffer
     }
 
 }