improve openglwindow example a bit

Change-Id: I50e00c33c100beab975d0fcbfc4ccdd496cccbaf
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>

examples/gui/openglwindow/main.cpp

@@ -80,7 +80,7 @@ int main(int argc, char **argv)
     QGuiApplication app(argc, argv);
 
     QSurfaceFormat format;
-    format.setSamples(4);
+    format.setSamples(16);
 
     TriangleWindow window;
     window.setFormat(format);
@@ -136,7 +136,8 @@ void TriangleWindow::initialize()
 //! [5]
 void TriangleWindow::render()
 {
-    glViewport(0, 0, width(), height());
+    const qreal retinaScale = devicePixelRatio();
+    glViewport(0, 0, width() * retinaScale, height() * retinaScale);
 
     glClear(GL_COLOR_BUFFER_BIT);
 

examples/gui/openglwindow/openglwindow.cpp

@@ -99,6 +99,7 @@ bool OpenGLWindow::event(QEvent *event)
 {
     switch (event->type()) {
     case QEvent::UpdateRequest:
+        m_update_pending = false;
         renderNow();
         return true;
     default:
@@ -113,14 +114,6 @@ void OpenGLWindow::exposeEvent(QExposeEvent *event)
     if (isExposed())
         renderNow();
 }
-
-void OpenGLWindow::resizeEvent(QResizeEvent *event)
-{
-    Q_UNUSED(event);
-
-    if (isExposed())
-        renderNow();
-}
 //! [3]
 
 //! [4]
@@ -129,8 +122,6 @@ void OpenGLWindow::renderNow()
     if (!isExposed())
         return;
 
-    m_update_pending = false;
-
     bool needsInitialize = false;
 
     if (!m_context) {

examples/gui/openglwindow/openglwindow.h

@@ -70,7 +70,6 @@ protected:
     bool event(QEvent *event);
 
     void exposeEvent(QExposeEvent *event);
-    void resizeEvent(QResizeEvent *event);
 
 private:
     bool m_update_pending;