add visual scope

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
+        );
+    }
 }