add scope widget

src/ui/MainWindow.cpp

@@ -16,7 +16,7 @@ MainWindow::MainWindow(QWidget *parent) :
     setFocusPolicy(Qt::StrongFocus);
 
     // connect scope
-    ui_->scopeWidget->setScopeBuffer(&audioEngine_->scopeBuffer());
+    ui_->scope->setScopeBuffer(&audio_->scopeBuffer());
 
     // Connect buttons to slots
     connect(ui_->buttonReset, &QPushButton::clicked, this, &MainWindow::onResetClicked);

src/ui/MainWindow.ui

@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>800</width>
-    <height>800</height>
+    <height>600</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -39,7 +39,7 @@
     <property name="geometry">
      <rect>
       <x>150</x>
-      <y>130</y>
+      <y>230</y>
       <width>500</width>
       <height>360</height>
      </rect>
@@ -55,7 +55,7 @@
     <property name="geometry">
      <rect>
       <x>200</x>
-      <y>540</y>
+      <y>20</y>
       <width>400</width>
       <height>200</height>
      </rect>

src/ui/widgets/Scope/Scope.cpp

@@ -0,0 +1,62 @@
+
+#include "Scope.h"
+#include "ui_Scope.h"
+
+#include "../../../synth/ScopeBuffer.h"
+
+#include <QPainter>
+#include <iostream>
+
+Scope::Scope(QWidget* parent) : QWidget(parent), ui_(new Ui::Scope), samples_(512) {
+    
+    timer_.setInterval(16); // ~60 hz
+    connect(&timer_, &QTimer::timeout, this, QOverload<>::of(&Scope::update));
+    timer_.start();
+}
+
+Scope::~Scope() {
+    delete ui_;
+}
+
+void Scope::setScopeBuffer(ScopeBuffer* buffer) {
+    buffer_ = buffer;
+}
+
+void Scope::paintEvent(QPaintEvent*) {
+    if (!buffer_) return;
+
+    int32_t wavelength = buffer_->wavelength();
+    int32_t trigger = buffer_->trigger();
+
+    buffer_->read(samples_);
+    
+    // auto scale amplitude. disabled because it hides the envelope effects
+    float maxAmp = 1.0f;
+    //for (float s : samples_) {
+    //    maxAmp = std::max(maxAmp, std::abs(s));
+    //}
+    // TODO: if you get really bored you can start adding scope display options
+        
+    float scaleY = (height() * 0.45f) / maxAmp;
+    float midY = height() / 2.0f;
+
+    QPainter p(this);
+    QColor gray(20, 20, 20);
+    p.fillRect(rect(), gray);
+
+    // got caught playing around
+    QPen pen;
+    pen.setWidthF(2.0f);
+    QColor green(50, 255, 70);
+    pen.setColor(green);
+    p.setPen(pen);
+
+    for (int32_t i = 1; i < samples_.size(); i++) {
+        p.drawLine(
+            (i - 1) * width() / samples_.size(),
+            midY - samples_[i - 1] * scaleY,
+            i * width() / samples_.size(),
+            midY - samples_[i] * scaleY
+        );
+    }
+}

src/ui/widgets/Scope/Scope.h

@@ -0,0 +1,35 @@
+
+#pragma once
+
+#include <QWidget>
+#include <QTimer>
+#include <vector>
+
+// forward declaration
+class ScopeBuffer;
+
+QT_BEGIN_NAMESPACE
+namespace Ui { class Scope; }
+QT_END_NAMESPACE
+
+class Scope : public QWidget {
+    Q_OBJECT
+public:
+    explicit Scope(QWidget* parent = nullptr);
+    ~Scope();
+
+    void setScopeBuffer(ScopeBuffer* buffer);
+
+protected:
+    // autocalled on QT's refresh loop
+    // scope drawing happens here
+    void paintEvent(QPaintEvent*) override;
+
+private:
+
+    Ui::Scope* ui_;
+
+    ScopeBuffer* buffer_ = nullptr;
+    std::vector<float> samples_;
+    QTimer timer_;
+};

src/ui/widgets/Scope/Scope.ui

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>Scope</class>
+ <widget class="QWidget" name="Scope">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>400</width>
+    <height>200</height>
+   </rect>
+  </property>
+  <property name="sizePolicy">
+   <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
+    <horstretch>0</horstretch>
+    <verstretch>0</verstretch>
+   </sizepolicy>
+  </property>
+  <property name="windowTitle">
+   <string>Form</string>
+  </property>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>