8 files changed, 30 insertions, 16 deletions
diff --git a/examples/opengl/contextinfo/renderwindow.cpp b/examples/opengl/contextinfo/renderwindow.cpp
index 2ac2a38afb..21b7434be6 100644
--- a/examples/opengl/contextinfo/renderwindow.cpp
+++ b/examples/opengl/contextinfo/renderwindow.cpp
@@ -181,6 +181,13 @@ void RenderWindow::setupVertexAttribs()
     m_vbo.release();
 }
 
+bool RenderWindow::event(QEvent *ev)
+{
+    if (ev->type() == QEvent::UpdateRequest)
+        render();
+    return QWindow::event(ev);
+}
+
 void RenderWindow::render()
 {
     if (!m_context->makeCurrent(this)) {
@@ -227,9 +234,5 @@ void RenderWindow::render()
 
     m_angle += 1.0f;
 
-    // Instead of 0 wait a few more milliseconds before rendering again. This is
-    // only here to make the UI widgets more responsive on slower machines. We
-    // can afford it since our rendering is so lightweight.
-    const int interval = 5;
-    QTimer::singleShot(interval, this, &RenderWindow::render);
+    requestUpdate();
 }
diff --git a/examples/opengl/contextinfo/renderwindow.h b/examples/opengl/contextinfo/renderwindow.h
index c148b71c3c..1b4a79dfcf 100644
--- a/examples/opengl/contextinfo/renderwindow.h
+++ b/examples/opengl/contextinfo/renderwindow.h
@@ -72,6 +72,9 @@ signals:
     void ready();
     void error(const QString &msg);
 
+protected:
+    bool event(QEvent *ev) override;
+
 private slots:
     void render();
 
diff --git a/examples/opengl/contextinfo/widget.cpp b/examples/opengl/contextinfo/widget.cpp
index a5d9e98bf8..b1b7076503 100644
--- a/examples/opengl/contextinfo/widget.cpp
+++ b/examples/opengl/contextinfo/widget.cpp
@@ -387,7 +387,7 @@ void Widget::renderWindowReady()
     QList<QByteArray> extensionList = context->extensions().toList();
     std::sort(extensionList.begin(), extensionList.end());
     m_extensions->append(tr("Found %1 extensions:").arg(extensionList.count()));
-    Q_FOREACH (const QByteArray &ext, extensionList)
+    for (const QByteArray &ext : qAsConst(extensionList))
         m_extensions->append(QString::fromLatin1(ext));
 
     m_output->moveCursor(QTextCursor::Start);
diff --git a/examples/opengl/hellowindow/hellowindow.cpp b/examples/opengl/hellowindow/hellowindow.cpp
index a978e19b79..1c1259de13 100644
--- a/examples/opengl/hellowindow/hellowindow.cpp
+++ b/examples/opengl/hellowindow/hellowindow.cpp
@@ -98,6 +98,15 @@ void HelloWindow::exposeEvent(QExposeEvent *)
         m_renderer->render();
 }
 
+bool HelloWindow::event(QEvent *ev)
+{
+    if (ev->type() == QEvent::UpdateRequest) {
+        m_renderer->render();
+        requestUpdate();
+    }
+    return QWindow::event(ev);
+}
+
 void HelloWindow::mousePressEvent(QMouseEvent *)
 {
     updateColor();
@@ -132,7 +141,7 @@ void Renderer::setAnimating(HelloWindow *window, bool animating)
     if (animating) {
         m_windows << window;
         if (m_windows.size() == 1)
-            QTimer::singleShot(0, this, &Renderer::render);
+            window->requestUpdate();
     } else {
         m_currentWindow = 0;
         m_windows.removeOne(window);
@@ -196,8 +205,6 @@ void Renderer::render()
     m_context->swapBuffers(surface);
 
     m_fAngle += 1.0f;
-
-    QTimer::singleShot(0, this, &Renderer::render);
 }
 
 Q_GLOBAL_STATIC(QMutex, initMutex)
diff --git a/examples/opengl/hellowindow/hellowindow.h b/examples/opengl/hellowindow/hellowindow.h
index e92e45a125..e6d7970cfc 100644
--- a/examples/opengl/hellowindow/hellowindow.h
+++ b/examples/opengl/hellowindow/hellowindow.h
@@ -112,11 +112,12 @@ public:
     QColor color() const;
     void updateColor();
 
+protected:
+    bool event(QEvent *ev) override;
     void exposeEvent(QExposeEvent *event) override;
-
-private:
     void mousePressEvent(QMouseEvent *) override;
 
+private:
     int m_colorIndex;
     QColor m_color;
     const QSharedPointer<Renderer> m_renderer;
diff --git a/examples/opengl/legacy/overpainting/glwidget.cpp b/examples/opengl/legacy/overpainting/glwidget.cpp
index 1ec7bd731c..f98d043c5c 100644
--- a/examples/opengl/legacy/overpainting/glwidget.cpp
+++ b/examples/opengl/legacy/overpainting/glwidget.cpp
@@ -201,7 +201,7 @@ void GLWidget::paintEvent(QPaintEvent *event)
 //! [10]
     QPainter painter(this);
     painter.setRenderHint(QPainter::Antialiasing);
-    foreach (Bubble *bubble, bubbles) {
+    for (Bubble *bubble : qAsConst(bubbles)) {
         if (bubble->rect().intersects(event->rect()))
             bubble->drawBubble(&painter);
     }
diff --git a/examples/opengl/qopenglwidget/glwidget.cpp b/examples/opengl/qopenglwidget/glwidget.cpp
index 3fe919f94b..946b2bec67 100644
--- a/examples/opengl/qopenglwidget/glwidget.cpp
+++ b/examples/opengl/qopenglwidget/glwidget.cpp
@@ -385,10 +385,10 @@ void GLWidget::paintGL()
 
     painter.endNativePainting();
 
-    if (m_showBubbles)
-        foreach (Bubble *bubble, m_bubbles) {
+    if (m_showBubbles) {
+        for (Bubble *bubble : qAsConst(m_bubbles))
             bubble->drawBubble(&painter);
-        }
+    }
 
     if (const int elapsed = m_time.elapsed()) {
         QString framesPerSecond;
diff --git a/examples/opengl/qopenglwidget/mainwindow.cpp b/examples/opengl/qopenglwidget/mainwindow.cpp
index 4bd123628f..6fab3df79e 100644
--- a/examples/opengl/qopenglwidget/mainwindow.cpp
+++ b/examples/opengl/qopenglwidget/mainwindow.cpp
@@ -176,7 +176,7 @@ void MainWindow::timerUsageChanged(bool enabled)
         m_timer->start();
     } else {
         m_timer->stop();
-        foreach (QOpenGLWidget *w, m_glWidgets)
+        for (QOpenGLWidget *w : qAsConst(m_glWidgets))
             w->update();
     }
 }