Performance improvements

osciwidget.cpp

@@ -8,110 +8,26 @@
 #include <QTimerEvent>
 
 OsciWidget::OsciWidget(QWidget *parent) :
-    QWidget{parent},
+    QOpenGLWidget{parent},
     m_redrawTimerId(startTimer(1000/m_fps))
 {
-    resizePixmap();
     m_fpsTimer.start();
 }
 
-int OsciWidget::blend() const
-{
-    return m_blend;
-}
-
-float OsciWidget::factor() const
-{
-    return m_factor;
-}
-
-float OsciWidget::glow() const
-{
-    return m_glow;
-}
-
-int OsciWidget::fps() const
-{
-    return m_fps;
-}
-
-void OsciWidget::setBlend(int blend)
-{
-    if (blend == m_blend)
-        return;
-
-    qDebug() << blend;
-
-    m_blend = blend;
-}
-
-void OsciWidget::setFactor(float factor)
-{
-    qDebug() << factor;
-    m_factor = factor;
-}
-
-void OsciWidget::setGlow(float glow)
-{
-    qDebug() << glow;
-    m_glow = glow;
-}
-
 void OsciWidget::setFps(int fps)
 {
-    qDebug() << fps;
     killTimer(m_redrawTimerId);
+
     m_fps = fps;
+
     m_redrawTimerId = startTimer(1000/m_fps);
 }
 
 void OsciWidget::renderSamples(const SamplePair *begin, const SamplePair *end)
 {
-    QPainter painter;
-    painter.begin(&m_pixmap);
-    painter.setCompositionMode(QPainter::CompositionMode_Plus);
+    m_callbacksCounter++;
 
-    QPen pen;
-    pen.setWidth(2);
-    pen.setColor(QColor(0, 255, 0));
-    painter.setPen(pen);
-
-    // Paint from center
-    painter.translate(m_pixmap.width()/2, m_pixmap.height()/2);
-
-    const auto pointToCoordinates = [width=m_pixmap.width()/2,height=m_pixmap.height()/2,factor=m_factor](const QPointF &point)
-    {
-        return QPoint{
-            int(point.x() * factor * width),
-            int(point.y() * factor * height)
-        };
-    };
-
-    for (auto i = begin; i < end; i++)
-    {
-        const QPointF p{
-            float(i->x) / std::numeric_limits<qint16>::max(),
-            float(-i->y) / std::numeric_limits<qint16>::max()
-        };
-
-        const QLineF line(m_lastPoint, p);
-
-        auto brightness = 1.f / line.length() / m_glow;
-        if (line.length() == 0.f || brightness > 255.f)
-            brightness = 255.f;
-
-        painter.setOpacity(brightness);
-
-        painter.drawLine(pointToCoordinates(m_lastPoint), pointToCoordinates(p));
-
-        m_lastPoint = p;
-    }
-
-    painter.resetTransform();
-    painter.setCompositionMode(QPainter::CompositionMode_Multiply);
-    painter.fillRect(m_pixmap.rect(), QColor(m_blend,m_blend,m_blend));
-
-    painter.end();
+    m_buffer.insert(m_buffer.end(), begin, end);
 }
 
 void OsciWidget::paintEvent(QPaintEvent *event)
@@ -121,25 +37,64 @@ void OsciWidget::paintEvent(QPaintEvent *event)
     m_frameCounter++;
     if (m_fpsTimer.hasExpired(1000))
     {
-        m_displayFrameCounter = m_frameCounter;
+        m_statsDisplay = QString("%0FPS (%1 callbacks)").arg(m_frameCounter).arg(m_callbacksCounter);
         m_frameCounter = 0;
+        m_callbacksCounter = 0;
         m_fpsTimer.restart();
     }
 
     QPainter painter;
     painter.begin(this);
-    painter.drawPixmap(0, 0, m_pixmap);
 
+    // draw background
+    painter.setBrush(Qt::black);
+    painter.drawRect(rect());
+
+    // drawing new lines ontop
+    QPen pen;
+    pen.setWidth(2);
+    pen.setColor(QColor(0, 255, 0));
+    painter.setPen(pen);
+    painter.translate(width()/2, height()/2);
+    painter.setCompositionMode(QPainter::CompositionMode_Plus);
+
+    const auto pointToCoordinates = [width=width()/2,height=height()/2,factor=m_factor](const QPointF &point)
+    {
+        return QPoint{
+            int(point.x() * factor * width),
+            int(point.y() * factor * height)
+        };
+    };
+
+    for (const auto &i : m_buffer)
+    {
+        const QPointF p{
+            float(i.first) / std::numeric_limits<qint16>::max(),
+            float(-i.second) / std::numeric_limits<qint16>::max()
+        };
+
+        const QLineF line(m_lastPoint, p);
+
+        painter.setOpacity(std::min(1.0, 1. / ((line.length() * 100) + 1)));
+
+        painter.drawLine(pointToCoordinates(m_lastPoint), pointToCoordinates(p));
+
+        m_lastPoint = p;
+    }
+
+    painter.resetTransform();
+    painter.setOpacity(1);
+
+    m_buffer.clear();
+
+    // draw stats
     painter.setPen(Qt::white);
     painter.setBrush(Qt::white);
     QFont font;
     font.setPixelSize(24);
-    painter.drawText(20, 20, QString("%0FPS").arg(m_displayFrameCounter));
+    painter.drawText(20, 20, m_statsDisplay);
 
     painter.end();
-
-    if (m_pixmap.rect() != rect())
-        qDebug() << m_pixmap.rect() << rect();
 }
 
 void OsciWidget::timerEvent(QTimerEvent *event)
@@ -148,15 +103,3 @@ void OsciWidget::timerEvent(QTimerEvent *event)
     if (event->timerId() == m_redrawTimerId)
         repaint();
 }
-
-void OsciWidget::resizeEvent(QResizeEvent *event)
-{
-    QWidget::resizeEvent(event);
-    resizePixmap();
-}
-
-void OsciWidget::resizePixmap()
-{
-    m_pixmap = QPixmap(size());
-    m_pixmap.fill(QColor{});
-}