Polish code of some opengl examples

Change-Id: If24ae1845176fc525cf6a239a5079f4802f8df3f
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

29 files changed, 182 insertions, 255 deletions

diff --git a/examples/opengl/2dpainting/glwidget.cpp b/examples/opengl/2dpainting/glwidget.cpp
index 23065a0b42..e1e40ea84c 100644
--- a/examples/opengl/2dpainting/glwidget.cpp
+++ b/examples/opengl/2dpainting/glwidget.cpp
@@ -38,10 +38,11 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
 #include "glwidget.h"
 #include "helper.h"
 
+#include <QTimer>
+
 //! [0]
 GLWidget::GLWidget(Helper *helper, QWidget *parent)
     : QGLWidget(QGLFormat(QGL::SampleBuffers), parent), helper(helper)
diff --git a/examples/opengl/2dpainting/glwidget.h b/examples/opengl/2dpainting/glwidget.h
index f8e44f8a3e..3540810983 100644
--- a/examples/opengl/2dpainting/glwidget.h
+++ b/examples/opengl/2dpainting/glwidget.h
@@ -45,10 +45,6 @@
 
 //! [0]
 class Helper;
-QT_BEGIN_NAMESPACE
-class QPaintEvent;
-class QWidget;
-QT_END_NAMESPACE
 
 class GLWidget : public QGLWidget
 {
diff --git a/examples/opengl/2dpainting/helper.cpp b/examples/opengl/2dpainting/helper.cpp
index b412dc11dc..168df2aff3 100644
--- a/examples/opengl/2dpainting/helper.cpp
+++ b/examples/opengl/2dpainting/helper.cpp
@@ -38,9 +38,12 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
 #include "helper.h"
 
+#include <QPainter>
+#include <QPaintEvent>
+#include <QWidget>
+
 //! [0]
 Helper::Helper()
 {
@@ -70,14 +73,15 @@ void Helper::paint(QPainter *painter, QPaintEvent *event, int elapsed)
     painter->setPen(circlePen);
     painter->rotate(elapsed * 0.030);
 
-    qreal r = elapsed/1000.0;
+    qreal r = elapsed / 1000.0;
     int n = 30;
     for (int i = 0; i < n; ++i) {
         painter->rotate(30);
-        qreal radius = 0 + 120.0*((i+r)/n);
-        qreal circleRadius = 1 + ((i+r)/n)*20;
+        qreal factor = (i + r) / n;
+        qreal radius = 0 + 120.0 * factor;
+        qreal circleRadius = 1 + factor * 20;
         painter->drawEllipse(QRectF(radius, -circleRadius,
-                                    circleRadius*2, circleRadius*2));
+                                    circleRadius * 2, circleRadius * 2));
     }
     painter->restore();
 //! [2]
@@ -85,6 +89,6 @@ void Helper::paint(QPainter *painter, QPaintEvent *event, int elapsed)
 //! [3]
     painter->setPen(textPen);
     painter->setFont(textFont);
-    painter->drawText(QRect(-50, -50, 100, 100), Qt::AlignCenter, "Qt");
+    painter->drawText(QRect(-50, -50, 100, 100), Qt::AlignCenter, QStringLiteral("Qt"));
 }
 //! [3]
diff --git a/examples/opengl/2dpainting/helper.h b/examples/opengl/2dpainting/helper.h
index 10bb2a5a9c..47f4c96639 100644
--- a/examples/opengl/2dpainting/helper.h
+++ b/examples/opengl/2dpainting/helper.h
@@ -44,11 +44,7 @@
 #include <QBrush>
 #include <QFont>
 #include <QPen>
-
-QT_BEGIN_NAMESPACE
-class QPainter;
-class QPaintEvent;
-QT_END_NAMESPACE
+#include <QWidget>
 
 //! [0]
 class Helper
diff --git a/examples/opengl/2dpainting/main.cpp b/examples/opengl/2dpainting/main.cpp
index 3374e57964..903795685f 100644
--- a/examples/opengl/2dpainting/main.cpp
+++ b/examples/opengl/2dpainting/main.cpp
@@ -38,9 +38,10 @@
 **
 ****************************************************************************/
 
-#include <QApplication>
 #include "window.h"
 
+#include <QApplication>
+
 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);
diff --git a/examples/opengl/2dpainting/widget.cpp b/examples/opengl/2dpainting/widget.cpp
index 49ce8b1329..832f37eb36 100644
--- a/examples/opengl/2dpainting/widget.cpp
+++ b/examples/opengl/2dpainting/widget.cpp
@@ -38,10 +38,11 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
 #include "widget.h"
 #include "helper.h"
 
+#include <QPainter>
+#include <QTimer>
 
 //! [0]
 Widget::Widget(Helper *helper, QWidget *parent)
diff --git a/examples/opengl/2dpainting/widget.h b/examples/opengl/2dpainting/widget.h
index 7d665b3952..ccf424330c 100644
--- a/examples/opengl/2dpainting/widget.h
+++ b/examples/opengl/2dpainting/widget.h
@@ -45,9 +45,6 @@
 
 //! [0]
 class Helper;
-QT_BEGIN_NAMESPACE
-class QPaintEvent;
-QT_END_NAMESPACE
 
 class Widget : public QWidget
 {
diff --git a/examples/opengl/2dpainting/window.cpp b/examples/opengl/2dpainting/window.cpp
index 700d0caaa8..b6aba2a945 100644
--- a/examples/opengl/2dpainting/window.cpp
+++ b/examples/opengl/2dpainting/window.cpp
@@ -38,15 +38,19 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
 #include "glwidget.h"
 #include "widget.h"
 #include "window.h"
 
+#include <QGridLayout>
+#include <QLabel>
+#include <QTimer>
+
 //! [0]
 Window::Window()
-    : QWidget()
 {
+    setWindowTitle(tr("2D Painting on Native and OpenGL Widgets"));
+
     Widget *native = new Widget(&helper, this);
     GLWidget *openGL = new GLWidget(&helper, this);
     QLabel *nativeLabel = new QLabel(tr("Native"));
@@ -65,7 +69,5 @@ Window::Window()
     connect(timer, SIGNAL(timeout()), native, SLOT(animate()));
     connect(timer, SIGNAL(timeout()), openGL, SLOT(animate()));
     timer->start(50);
-
-    setWindowTitle(tr("2D Painting on Native and OpenGL Widgets"));
 }
 //! [0]
diff --git a/examples/opengl/2dpainting/window.h b/examples/opengl/2dpainting/window.h
index 263572637e..acded9895f 100644
--- a/examples/opengl/2dpainting/window.h
+++ b/examples/opengl/2dpainting/window.h
@@ -41,14 +41,9 @@
 #ifndef WINDOW_H
 #define WINDOW_H
 
-#include <QWidget>
-
 #include "helper.h"
 
-QT_BEGIN_NAMESPACE
-class QLabel;
-class QWidget;
-QT_END_NAMESPACE
+#include <QWidget>
 
 //! [0]
 class Window : public QWidget
diff --git a/examples/opengl/cube/geometryengine.cpp b/examples/opengl/cube/geometryengine.cpp
index d8dfeab822..277a6e9cfc 100644
--- a/examples/opengl/cube/geometryengine.cpp
+++ b/examples/opengl/cube/geometryengine.cpp
@@ -49,14 +49,13 @@ struct VertexData
     QVector2D texCoord;
 };
 
-GeometryEngine::GeometryEngine() : vboIds(new GLuint[2])
+GeometryEngine::GeometryEngine()
 {    
 }
 
 GeometryEngine::~GeometryEngine()
 {
     glDeleteBuffers(2, vboIds);
-    delete[] vboIds;
 }
 
 void GeometryEngine::init()
diff --git a/examples/opengl/cube/geometryengine.h b/examples/opengl/cube/geometryengine.h
index 2716b05c2b..6a15c3ce03 100644
--- a/examples/opengl/cube/geometryengine.h
+++ b/examples/opengl/cube/geometryengine.h
@@ -41,8 +41,8 @@
 #ifndef GEOMETRYENGINE_H
 #define GEOMETRYENGINE_H
 
-#include <QtOpenGL/QGLFunctions>
-#include <QtOpenGL/QGLShaderProgram>
+#include <QGLFunctions>
+#include <QGLShaderProgram>
 
 class GeometryEngine : protected QGLFunctions
 {
@@ -51,14 +51,12 @@ public:
     virtual ~GeometryEngine();
 
     void init();
-
     void drawCubeGeometry(QGLShaderProgram *program);
 
 private:
     void initCubeGeometry();
 
-    GLuint *vboIds;
-
+    GLuint vboIds[2];
 };
 
 #endif // GEOMETRYENGINE_H
diff --git a/examples/opengl/cube/main.cpp b/examples/opengl/cube/main.cpp
index fbc1d93e4a..fdae1caa16 100644
--- a/examples/opengl/cube/main.cpp
+++ b/examples/opengl/cube/main.cpp
@@ -47,16 +47,15 @@
 
 int main(int argc, char *argv[])
 {
-    QApplication a(argc, argv);
-    a.setApplicationName("cube");
-    a.setApplicationVersion("0.1");
-#ifndef QT_NO_OPENGL
-    MainWidget w;
-    w.resize(640, 480);
-    w.show();
+    QApplication app(argc, argv);
+    app.setApplicationName("cube");
+    app.setApplicationVersion("0.1");
+#ifdef QT_NO_OPENGL
+    MainWidget widget;
+    widget.show();
 #else
-    QLabel * notifyLabel = new QLabel("OpenGL Support required");
-    notifyLabel->show();
+    QLabel note("OpenGL Support required");
+    note.show();
 #endif
-    return a.exec();
+    return app.exec();
 }
diff --git a/examples/opengl/cube/mainwidget.cpp b/examples/opengl/cube/mainwidget.cpp
index 055dcf49cf..4a42eca159 100644
--- a/examples/opengl/cube/mainwidget.cpp
+++ b/examples/opengl/cube/mainwidget.cpp
@@ -40,39 +40,26 @@
 
 #include "mainwidget.h"
 
-#include "geometryengine.h"
-
-#include <QtOpenGL/QGLShaderProgram>
-
-#include <QBasicTimer>
 #include <QMouseEvent>
-#include <QDebug>
 
 #include <math.h>
 #include <locale.h>
 
 MainWidget::MainWidget(QWidget *parent) :
     QGLWidget(parent),
-    timer(new QBasicTimer),
-    program(new QGLShaderProgram),
-    geometries(new GeometryEngine),
     angularSpeed(0)
 {
 }
 
 MainWidget::~MainWidget()
 {
-    delete timer; timer = 0;
-    delete program; program = 0;
-    delete geometries; geometries = 0;
-
     deleteTexture(texture);
 }
 
 //! [0]
 void MainWidget::mousePressEvent(QMouseEvent *e)
 {
-    // Saving mouse press position
+    // Save mouse press position
     mousePressPosition = QVector2D(e->localPos());
 }
 
@@ -97,17 +84,15 @@ void MainWidget::mouseReleaseEvent(QMouseEvent *e)
 //! [0]
 
 //! [1]
-void MainWidget::timerEvent(QTimerEvent *e)
+void MainWidget::timerEvent(QTimerEvent *)
 {
-    Q_UNUSED(e);
-
     // Decrease angular speed (friction)
     angularSpeed *= 0.99;
 
     // Stop rotation when speed goes below threshold
-    if (angularSpeed < 0.01)
+    if (angularSpeed < 0.01) {
         angularSpeed = 0.0;
-    else {
+    } else {
         // Update rotation
         rotation = QQuaternion::fromAxisAndAngle(rotationAxis, angularSpeed) * rotation;
 
@@ -120,13 +105,8 @@ void MainWidget::timerEvent(QTimerEvent *e)
 void MainWidget::initializeGL()
 {
     initializeGLFunctions();
-
     qglClearColor(Qt::black);
-
-    qDebug() << "Initializing shaders...";
     initShaders();
-
-    qDebug() << "Initializing textures...";
     initTextures();
 
 //! [2]
@@ -137,33 +117,32 @@ void MainWidget::initializeGL()
     glEnable(GL_CULL_FACE);
 //! [2]
 
-    qDebug() << "Initializing geometries...";
-    geometries->init();
+    geometries.init();
 
-    // using QBasicTimer because its faster that QTimer
-    timer->start(12, this);
+    // Use QBasicTimer because its faster than QTimer
+    timer.start(12, this);
 }
 
 //! [3]
 void MainWidget::initShaders()
 {
-    // Overriding system locale until shaders are compiled
+    // Override system locale until shaders are compiled
     setlocale(LC_NUMERIC, "C");
 
-    // Compiling vertex shader
-    if (!program->addShaderFromSourceFile(QGLShader::Vertex, ":/vshader.glsl"))
+    // Compile vertex shader
+    if (!program.addShaderFromSourceFile(QGLShader::Vertex, ":/vshader.glsl"))
         close();
 
-    // Compiling fragment shader
-    if (!program->addShaderFromSourceFile(QGLShader::Fragment, ":/fshader.glsl"))
+    // Compile fragment shader
+    if (!program.addShaderFromSourceFile(QGLShader::Fragment, ":/fshader.glsl"))
         close();
 
-    // Linking shader pipeline
-    if (!program->link())
+    // Link shader pipeline
+    if (!program.link())
         close();
 
-    // Binding shader pipeline for use
-    if (!program->bind())
+    // Bind shader pipeline for use
+    if (!program.bind())
         close();
 
     // Restore system locale
@@ -174,7 +153,7 @@ void MainWidget::initShaders()
 //! [4]
 void MainWidget::initTextures()
 {
-    // Loading cube.png
+    // Load cube.png image
     glEnable(GL_TEXTURE_2D);
     texture = bindTexture(QImage(":/cube.png"));
 
@@ -198,7 +177,7 @@ void MainWidget::resizeGL(int w, int h)
     glViewport(0, 0, w, h);
 
     // Calculate aspect ratio
-    qreal aspect = (qreal)w / ((qreal)h?h:1);
+    qreal aspect = qreal(w) / qreal(h ? h : 1);
 
     // Set near plane to 3.0, far plane to 7.0, field of view 45 degrees
     const qreal zNear = 3.0, zFar = 7.0, fov = 45.0;
@@ -223,12 +202,12 @@ void MainWidget::paintGL()
     matrix.rotate(rotation);
 
     // Set modelview-projection matrix
-    program->setUniformValue("mvp_matrix", projection * matrix);
+    program.setUniformValue("mvp_matrix", projection * matrix);
 //! [6]
 
-    // Using texture unit 0 which contains cube.png
-    program->setUniformValue("texture", 0);
+    // Use texture unit 0 which contains cube.png
+    program.setUniformValue("texture", 0);
 
     // Draw cube geometry
-    geometries->drawCubeGeometry(program);
+    geometries.drawCubeGeometry(&program);
 }
diff --git a/examples/opengl/cube/mainwidget.h b/examples/opengl/cube/mainwidget.h
index bd30ea93a0..cebfb30999 100644
--- a/examples/opengl/cube/mainwidget.h
+++ b/examples/opengl/cube/mainwidget.h
@@ -41,30 +41,26 @@
 #ifndef MAINWIDGET_H
 #define MAINWIDGET_H
 
-#include <QtOpenGL/QGLWidget>
-#include <QtOpenGL/QGLFunctions>
+#include "geometryengine.h"
 
+#include <QGLWidget>
+#include <QGLFunctions>
 #include <QMatrix4x4>
 #include <QQuaternion>
 #include <QVector2D>
+#include <QBasicTimer>
+#include <QGLShaderProgram>
 
-QT_BEGIN_NAMESPACE
-class QBasicTimer;
-class QGLShaderProgram;
-QT_END_NAMESPACE
 
 class GeometryEngine;
 
 class MainWidget : public QGLWidget, protected QGLFunctions
 {
     Q_OBJECT
+
 public:
     explicit MainWidget(QWidget *parent = 0);
-    virtual ~MainWidget();
-
-signals:
-
-public slots:
+    ~MainWidget();
 
 protected:
     void mousePressEvent(QMouseEvent *e);
@@ -79,9 +75,9 @@ protected:
     void initTextures();
 
 private:
-    QBasicTimer *timer;
-    QGLShaderProgram *program;
-    GeometryEngine *geometries;
+    QBasicTimer timer;
+    QGLShaderProgram program;
+    GeometryEngine geometries;
 
     GLuint texture;
 
diff --git a/examples/opengl/grabber/glwidget.cpp b/examples/opengl/grabber/glwidget.cpp
index 6d8ef0049f..00964c1a0f 100644
--- a/examples/opengl/grabber/glwidget.cpp
+++ b/examples/opengl/grabber/glwidget.cpp
@@ -38,12 +38,12 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-#include <QtOpenGL>
+#include "glwidget.h"
 
-#include <math.h>
+#include <QMouseEvent>
+#include <QTimer>
 
-#include "glwidget.h"
+#include <math.h>
 
 GLWidget::GLWidget(QWidget *parent)
     : QGLWidget(parent)
@@ -191,57 +191,52 @@ GLuint GLWidget::makeGear(const GLfloat *reflectance, GLdouble innerRadius,
     GLdouble r2 = outerRadius + toothSize / 2.0;
     GLdouble delta = (2.0 * Pi / toothCount) / 4.0;
     GLdouble z = thickness / 2.0;
-    int i, j;
 
     glShadeModel(GL_FLAT);
 
-    for (i = 0; i < 2; ++i) {
+    for (int i = 0; i < 2; ++i) {
         GLdouble sign = (i == 0) ? +1.0 : -1.0;
 
         glNormal3d(0.0, 0.0, sign);
 
         glBegin(GL_QUAD_STRIP);
-        for (j = 0; j <= toothCount; ++j) {
+        for (int j = 0; j <= toothCount; ++j) {
             GLdouble angle = 2.0 * Pi * j / toothCount;
-	    glVertex3d(r0 * cos(angle), r0 * sin(angle), sign * z);
-	    glVertex3d(r1 * cos(angle), r1 * sin(angle), sign * z);
-	    glVertex3d(r0 * cos(angle), r0 * sin(angle), sign * z);
-	    glVertex3d(r1 * cos(angle + 3 * delta), r1 * sin(angle + 3 * delta),
-                       sign * z);
+            glVertex3d(r0 * cos(angle), r0 * sin(angle), sign * z);
+            glVertex3d(r1 * cos(angle), r1 * sin(angle), sign * z);
+            glVertex3d(r0 * cos(angle), r0 * sin(angle), sign * z);
+            glVertex3d(r1 * cos(angle + 3 * delta), r1 * sin(angle + 3 * delta), sign * z);
         }
         glEnd();
 
         glBegin(GL_QUADS);
-        for (j = 0; j < toothCount; ++j) {
+        for (int j = 0; j < toothCount; ++j) {
             GLdouble angle = 2.0 * Pi * j / toothCount;
-	    glVertex3d(r1 * cos(angle), r1 * sin(angle), sign * z);
-	    glVertex3d(r2 * cos(angle + delta), r2 * sin(angle + delta),
-                       sign * z);
-	    glVertex3d(r2 * cos(angle + 2 * delta), r2 * sin(angle + 2 * delta),
-                       sign * z);
-	    glVertex3d(r1 * cos(angle + 3 * delta), r1 * sin(angle + 3 * delta),
-                       sign * z);
+            glVertex3d(r1 * cos(angle), r1 * sin(angle), sign * z);
+            glVertex3d(r2 * cos(angle + delta), r2 * sin(angle + delta), sign * z);
+            glVertex3d(r2 * cos(angle + 2 * delta), r2 * sin(angle + 2 * delta), sign * z);
+            glVertex3d(r1 * cos(angle + 3 * delta), r1 * sin(angle + 3 * delta), sign * z);
         }
         glEnd();
     }
 
     glBegin(GL_QUAD_STRIP);
-    for (i = 0; i < toothCount; ++i) {
-        for (j = 0; j < 2; ++j) {
-            GLdouble angle = 2.0 * Pi * (i + (j / 2.0)) / toothCount;
+    for (int i = 0; i < toothCount; ++i) {
+        for (int j = 0; j < 2; ++j) {
+            GLdouble angle = 2.0 * Pi * (i + j / 2.0) / toothCount;
             GLdouble s1 = r1;
             GLdouble s2 = r2;
             if (j == 1)
                 qSwap(s1, s2);
 
-	    glNormal3d(cos(angle), sin(angle), 0.0);
-	    glVertex3d(s1 * cos(angle), s1 * sin(angle), +z);
-	    glVertex3d(s1 * cos(angle), s1 * sin(angle), -z);
+            glNormal3d(cos(angle), sin(angle), 0.0);
+            glVertex3d(s1 * cos(angle), s1 * sin(angle), +z);
+            glVertex3d(s1 * cos(angle), s1 * sin(angle), -z);
 
-	    glNormal3d(s2 * sin(angle + delta) - s1 * sin(angle),
+            glNormal3d(s2 * sin(angle + delta) - s1 * sin(angle),
                        s1 * cos(angle) - s2 * cos(angle + delta), 0.0);
-	    glVertex3d(s2 * cos(angle + delta), s2 * sin(angle + delta), +z);
-	    glVertex3d(s2 * cos(angle + delta), s2 * sin(angle + delta), -z);
+            glVertex3d(s2 * cos(angle + delta), s2 * sin(angle + delta), +z);
+            glVertex3d(s2 * cos(angle + delta), s2 * sin(angle + delta), -z);
         }
     }
     glVertex3d(r1, 0.0, +z);
@@ -251,11 +246,11 @@ GLuint GLWidget::makeGear(const GLfloat *reflectance, GLdouble innerRadius,
     glShadeModel(GL_SMOOTH);
 
     glBegin(GL_QUAD_STRIP);
-    for (i = 0; i <= toothCount; ++i) {
-	GLdouble angle = i * 2.0 * Pi / toothCount;
-	glNormal3d(-cos(angle), -sin(angle), 0.0);
-	glVertex3d(r0 * cos(angle), r0 * sin(angle), +z);
-	glVertex3d(r0 * cos(angle), r0 * sin(angle), -z);
+    for (int i = 0; i <= toothCount; ++i) {
+        GLdouble angle = i * 2.0 * Pi / toothCount;
+        glNormal3d(-cos(angle), -sin(angle), 0.0);
+        glVertex3d(r0 * cos(angle), r0 * sin(angle), +z);
+        glVertex3d(r0 * cos(angle), r0 * sin(angle), -z);
     }
     glEnd();
 
diff --git a/examples/opengl/grabber/glwidget.h b/examples/opengl/grabber/glwidget.h
index 88a97ac8b0..6f48102111 100644
--- a/examples/opengl/grabber/glwidget.h
+++ b/examples/opengl/grabber/glwidget.h
@@ -94,4 +94,4 @@ private:
     QPoint lastPos;
 };
 
-#endif
+#endif // GLWIDGET_H
diff --git a/examples/opengl/grabber/main.cpp b/examples/opengl/grabber/main.cpp
index f03543e449..be0e7b11cc 100644
--- a/examples/opengl/grabber/main.cpp
+++ b/examples/opengl/grabber/main.cpp
@@ -38,14 +38,14 @@
 **
 ****************************************************************************/
 
-#include <QApplication>
-
 #include "mainwindow.h"
 
+#include <QApplication>
+
 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);
-    MainWindow mainWin;
-    mainWin.show();
+    MainWindow window;
+    window.show();
     return app.exec();
 }
diff --git a/examples/opengl/grabber/mainwindow.cpp b/examples/opengl/grabber/mainwindow.cpp
index a559649c55..e521b39dab 100644
--- a/examples/opengl/grabber/mainwindow.cpp
+++ b/examples/opengl/grabber/mainwindow.cpp
@@ -38,12 +38,11 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-#include <QtOpenGL>
-
 #include "glwidget.h"
 #include "mainwindow.h"
 
+#include <QtWidgets>
+
 MainWindow::MainWindow()
 {
     centralWidget = new QWidget;
diff --git a/examples/opengl/grabber/mainwindow.h b/examples/opengl/grabber/mainwindow.h
index 6f981c5381..552f902c07 100644
--- a/examples/opengl/grabber/mainwindow.h
+++ b/examples/opengl/grabber/mainwindow.h
@@ -44,12 +44,12 @@
 #include <QMainWindow>
 
 QT_BEGIN_NAMESPACE
-class QAction;
 class QLabel;
 class QMenu;
 class QScrollArea;
 class QSlider;
 QT_END_NAMESPACE
+
 class GLWidget;
 
 class MainWindow : public QMainWindow
@@ -91,4 +91,4 @@ private:
     QAction *aboutQtAct;
 };
 
-#endif
+#endif // MAINWINDOW_H
diff --git a/examples/opengl/hellowindow/hellowindow.cpp b/examples/opengl/hellowindow/hellowindow.cpp
index b5166abe50..b1140c4f1d 100644
--- a/examples/opengl/hellowindow/hellowindow.cpp
+++ b/examples/opengl/hellowindow/hellowindow.cpp
@@ -41,9 +41,6 @@
 #include "hellowindow.h"
 
 #include <QOpenGLContext>
-
-#include <QTimer>
-
 #include <qmath.h>
 
 Renderer::Renderer(const QSurfaceFormat &format, Renderer *share, QScreen *screen)
@@ -77,10 +74,8 @@ HelloWindow::HelloWindow(const QSharedPointer<Renderer> &renderer)
     updateColor();
 }
 
-void HelloWindow::exposeEvent(QExposeEvent *event)
+void HelloWindow::exposeEvent(QExposeEvent *)
 {
-    Q_UNUSED(event);
-
     render();
 
     if (!m_timer) {
@@ -109,10 +104,7 @@ void HelloWindow::updateColor()
     };
 
     m_color = colors[m_colorIndex];
-
-    m_colorIndex++;
-    if (m_colorIndex >= int(sizeof(colors) / sizeof(colors[0])))
-        m_colorIndex = 0;
+    m_colorIndex = 1 - m_colorIndex;
 }
 
 void Renderer::render(QSurface *surface, const QColor &color, const QSize &viewSize)
@@ -171,31 +163,29 @@ void Renderer::initialize()
     glClearColor(0.1f, 0.1f, 0.2f, 1.0f);
 
     QOpenGLShader *vshader = new QOpenGLShader(QOpenGLShader::Vertex, this);
-    const char *vsrc =
-        "attribute highp vec4 vertex;\n"
-        "attribute mediump vec3 normal;\n"
-        "uniform mediump mat4 matrix;\n"
-        "uniform lowp vec4 sourceColor;\n"
-        "varying mediump vec4 color;\n"
-        "void main(void)\n"
-        "{\n"
-        "    vec3 toLight = normalize(vec3(0.0, 0.3, 1.0));\n"
-        "    float angle = max(dot(normal, toLight), 0.0);\n"
-        "    vec3 col = sourceColor.rgb;\n"
-        "    color = vec4(col * 0.2 + col * 0.8 * angle, 1.0);\n"
-        "    color = clamp(color, 0.0, 1.0);\n"
-        "    gl_Position = matrix * vertex;\n"
-        "}\n";
-    vshader->compileSourceCode(vsrc);
+    vshader->compileSourceCode(
+        "attribute highp vec4 vertex;"
+        "attribute mediump vec3 normal;"
+        "uniform mediump mat4 matrix;"
+        "uniform lowp vec4 sourceColor;"
+        "varying mediump vec4 color;"
+        "void main(void)"
+        "{"
+        "    vec3 toLight = normalize(vec3(0.0, 0.3, 1.0));"
+        "    float angle = max(dot(normal, toLight), 0.0);"
+        "    vec3 col = sourceColor.rgb;"
+        "    color = vec4(col * 0.2 + col * 0.8 * angle, 1.0);"
+        "    color = clamp(color, 0.0, 1.0);"
+        "    gl_Position = matrix * vertex;"
+        "}");
 
     QOpenGLShader *fshader = new QOpenGLShader(QOpenGLShader::Fragment, this);
-    const char *fsrc =
-        "varying mediump vec4 color;\n"
-        "void main(void)\n"
-        "{\n"
-        "    gl_FragColor = color;\n"
-        "}\n";
-    fshader->compileSourceCode(fsrc);
+    fshader->compileSourceCode(
+        "varying mediump vec4 color;"
+        "void main(void)"
+        "{"
+        "    gl_FragColor = color;"
+        "}");
 
     m_program = new QOpenGLShaderProgram(this);
     m_program->addShader(vshader);
diff --git a/examples/opengl/hellowindow/hellowindow.h b/examples/opengl/hellowindow/hellowindow.h
index adb85c1a6e..27cae4be7d 100644
--- a/examples/opengl/hellowindow/hellowindow.h
+++ b/examples/opengl/hellowindow/hellowindow.h
@@ -40,21 +40,15 @@
 
 #include <QWindow>
 
-#include <QtGui/qopengl.h>
-#include <QtGui/qopenglshaderprogram.h>
-
 #include <QColor>
-#include <QTime>
+#include <QOpenGLShaderProgram>
 #include <QSharedPointer>
-
-QT_BEGIN_NAMESPACE
-class QOpenGLContext;
-class QTimer;
-QT_END_NAMESPACE
+#include <QTimer>
 
 class Renderer : public QObject
 {
     Q_OBJECT
+
 public:
     explicit Renderer(const QSurfaceFormat &format, Renderer *share = 0, QScreen *screen = 0);
 
@@ -89,6 +83,7 @@ private:
 class HelloWindow : public QWindow
 {
     Q_OBJECT
+
 public:
     explicit HelloWindow(const QSharedPointer<Renderer> &renderer);
 
diff --git a/examples/opengl/hellowindow/main.cpp b/examples/opengl/hellowindow/main.cpp
index 343160f755..e63b27d093 100644
--- a/examples/opengl/hellowindow/main.cpp
+++ b/examples/opengl/hellowindow/main.cpp
@@ -38,21 +38,22 @@
 **
 ****************************************************************************/
 
-#include <QGuiApplication>
+#include "hellowindow.h"
+
 #include <qpa/qplatformintegration.h>
 #include <private/qguiapplication_p.h>
+
+#include <QGuiApplication>
 #include <QScreen>
 #include <QThread>
 
-#include "hellowindow.h"
-
-int main(int argc, char **argv)
+int main(int argc, char *argv[])
 {
     QGuiApplication app(argc, argv);
 
     const bool multipleWindows =
         QGuiApplicationPrivate::platformIntegration()->hasCapability(QPlatformIntegration::ThreadedOpenGL)
-        && !QGuiApplication::arguments().contains(QLatin1String("--single"));
+        && !QGuiApplication::arguments().contains(QStringLiteral("--single"));
 
     QScreen *screen = QGuiApplication::primaryScreen();
 
@@ -71,7 +72,7 @@ int main(int argc, char **argv)
 
     HelloWindow *windowA = new HelloWindow(rendererA);
     windowA->setGeometry(QRect(center, windowSize).translated(-windowSize.width() - delta / 2, 0));
-    windowA->setTitle(QLatin1String("Thread A - Context A"));
+    windowA->setTitle(QStringLiteral("Thread A - Context A"));
     windowA->setVisible(true);
     windows.prepend(windowA);
 
@@ -85,13 +86,13 @@ int main(int argc, char **argv)
 
         HelloWindow *windowB = new HelloWindow(rendererA);
         windowB->setGeometry(QRect(center, windowSize).translated(delta / 2, 0));
-        windowB->setTitle(QLatin1String("Thread A - Context A"));
+        windowB->setTitle(QStringLiteral("Thread A - Context A"));
         windowB->setVisible(true);
         windows.prepend(windowB);
 
         HelloWindow *windowC = new HelloWindow(rendererB);
         windowC->setGeometry(QRect(center, windowSize).translated(-windowSize.width() / 2, windowSize.height() + delta));
-        windowC->setTitle(QLatin1String("Thread B - Context B"));
+        windowC->setTitle(QStringLiteral("Thread B - Context B"));
         windowC->setVisible(true);
         windows.prepend(windowC);
 
@@ -113,7 +114,7 @@ int main(int argc, char **argv)
             window->setGeometry(QRect(center, windowSize).translated(-windowSize.width() / 2, -windowSize.height() / 2));
 
             QChar id = QChar('B' + i);
-            window->setTitle(QLatin1String("Thread ") + id + QLatin1String(" - Context ") + id);
+            window->setTitle(QStringLiteral("Thread ") + id + QStringLiteral(" - Context ") + id);
             window->setVisible(true);
             windows.prepend(window);
         }
@@ -128,6 +129,7 @@ int main(int argc, char **argv)
 
     for (int i = 0; i < renderThreads.size(); ++i)
         renderThreads.at(i)->wait();
+
     qDeleteAll(windows);
     qDeleteAll(renderThreads);
 
diff --git a/examples/opengl/overpainting/bubble.cpp b/examples/opengl/overpainting/bubble.cpp
index 5f0e9710ea..0b3e3b8778 100644
--- a/examples/opengl/overpainting/bubble.cpp
+++ b/examples/opengl/overpainting/bubble.cpp
@@ -38,8 +38,6 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "bubble.h"
 
 Bubble::Bubble(const QPointF &position, qreal radius, const QPointF &velocity)
diff --git a/examples/opengl/overpainting/bubble.h b/examples/opengl/overpainting/bubble.h
index 2a3d27480b..42dedc6e8f 100644
--- a/examples/opengl/overpainting/bubble.h
+++ b/examples/opengl/overpainting/bubble.h
@@ -41,15 +41,7 @@
 #ifndef BUBBLE_H
 #define BUBBLE_H
 
-#include <QBrush>
-#include <QColor>
-#include <QPointF>
-#include <QRect>
-#include <QRectF>
-
-QT_BEGIN_NAMESPACE
-class QPainter;
-QT_END_NAMESPACE
+#include <QPainter>
 
 class Bubble
 {
@@ -72,4 +64,4 @@ private:
     QColor outerColor;
 };
 
-#endif
+#endif // BUBBLE_H
diff --git a/examples/opengl/overpainting/glwidget.cpp b/examples/opengl/overpainting/glwidget.cpp
index df546a125b..ea29325b6c 100644
--- a/examples/opengl/overpainting/glwidget.cpp
+++ b/examples/opengl/overpainting/glwidget.cpp
@@ -38,16 +38,16 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-#include <QtOpenGL>
-#include <stdlib.h>
-
-#include <math.h>
-
 #include "bubble.h"
 #include "qtlogo.h"
 #include "glwidget.h"
 
+#include <QMouseEvent>
+#include <QTime>
+
+#include <math.h>
+#include <stdlib.h>
+
 #ifndef GL_MULTISAMPLE
 #define GL_MULTISAMPLE  0x809D
 #endif
diff --git a/examples/opengl/overpainting/glwidget.h b/examples/opengl/overpainting/glwidget.h
index ce2b29d7f3..497d5e1ac4 100644
--- a/examples/opengl/overpainting/glwidget.h
+++ b/examples/opengl/overpainting/glwidget.h
@@ -41,19 +41,11 @@
 #ifndef GLWIDGET_H
 #define GLWIDGET_H
 
-#include <QBrush>
-#include <QFont>
-#include <QImage>
-#include <QPen>
 #include <QGLWidget>
 #include <QTimer>
 
 class Bubble;
 class QtLogo;
-QT_BEGIN_NAMESPACE
-class QPaintEvent;
-class QWidget;
-QT_END_NAMESPACE
 
 //! [0]
 class GLWidget : public QGLWidget
@@ -108,4 +100,4 @@ private:
 //! [4]
 };
 
-#endif
+#endif // GLWIDGET_H
diff --git a/examples/opengl/overpainting/main.cpp b/examples/opengl/overpainting/main.cpp
index c4758956ba..2d40a7f76b 100644
--- a/examples/opengl/overpainting/main.cpp
+++ b/examples/opengl/overpainting/main.cpp
@@ -38,9 +38,10 @@
 **
 ****************************************************************************/
 
-#include <QApplication>
 #include "glwidget.h"
 
+#include <QApplication>
+
 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);
diff --git a/examples/opengl/overpainting/overpainting.pro b/examples/opengl/overpainting/overpainting.pro
index 141c8cb7ce..aecc14751b 100644
--- a/examples/opengl/overpainting/overpainting.pro
+++ b/examples/opengl/overpainting/overpainting.pro
@@ -1,10 +1,12 @@
+QT += opengl widgets
+
 VPATH += ../shared
 INCLUDEPATH += ../shared
 
-QT += opengl widgets
 HEADERS = bubble.h \
     glwidget.h \
     qtlogo.h
+
 SOURCES = bubble.cpp \
     glwidget.cpp \
     main.cpp \
diff --git a/examples/opengl/shared/qtlogo.cpp b/examples/opengl/shared/qtlogo.cpp
index fa3d91c840..e49ed7e67c 100644
--- a/examples/opengl/shared/qtlogo.cpp
+++ b/examples/opengl/shared/qtlogo.cpp
@@ -38,14 +38,14 @@
 **
 ****************************************************************************/
 
+#include "qtlogo.h"
+
 #include <QGLWidget>
 #include <QMatrix4x4>
 #include <QVector3D>
 
 #include <qmath.h>
 
-#include "qtlogo.h"
-
 static const qreal tee_height = 0.311126;
 static const qreal cross_width = 0.25;
 static const qreal bar_thickness = 0.113137;
@@ -117,7 +117,7 @@ void Geometry::finalize()
 
 void Geometry::appendSmooth(const QVector3D &a, const QVector3D &n, int from)
 {
-    // Smooth normals are acheived by averaging the normals for faces meeting
+    // Smooth normals are achieved by averaging the normals for faces meeting
     // at a point.  First find the point in geometry already generated
     // (working backwards, since most often the points shared are between faces
     // recently added).
@@ -125,28 +125,27 @@ void Geometry::appendSmooth(const QVector3D &a, const QVector3D &n, int from)
     for ( ; v >= from; --v)
         if (qFuzzyCompare(vertices[v], a))
             break;
-    if (v < from)
-    {
-        // The vert was not found so add it as a new one, and initialize
+
+    if (v < from) {
+        // The vertex was not found so add it as a new one, and initialize
         // its corresponding normal
         v = vertices.count();
         vertices.append(a);
         normals.append(n);
-    }
-    else
-    {
+    } else {
         // Vert found, accumulate normals into corresponding normal slot.
         // Must call finalize once finished accumulating normals
         normals[v] += n;
     }
-    // In both cases (found or not) reference the vert via its index
+
+    // In both cases (found or not) reference the vertex via its index
     faces.append(v);
 }
 
 void Geometry::appendFaceted(const QVector3D &a, const QVector3D &n)
 {
-    // Faceted normals are achieved by duplicating the vert for every
-    // normal, so that faces meeting at a vert get a sharp edge.
+    // Faceted normals are achieved by duplicating the vertex for every
+    // normal, so that faces meeting at a vertex get a sharp edge.
     int v = vertices.count();
     vertices.append(a);
     normals.append(n);
@@ -189,32 +188,29 @@ void Patch::draw() const
 void Patch::addTri(const QVector3D &a, const QVector3D &b, const QVector3D &c, const QVector3D &n)
 {
     QVector3D norm = n.isNull() ? QVector3D::normal(a, b, c) : n;
-    if (sm == Smooth)
-    {
+
+    if (sm == Smooth) {
         geom->appendSmooth(a, norm, initv);
         geom->appendSmooth(b, norm, initv);
         geom->appendSmooth(c, norm, initv);
-    }
-    else
-    {
+    } else {
         geom->appendFaceted(a, norm);
         geom->appendFaceted(b, norm);
         geom->appendFaceted(c, norm);
     }
+
     count += 3;
 }
 
 void Patch::addQuad(const QVector3D &a, const QVector3D &b,  const QVector3D &c, const QVector3D &d)
 {
     QVector3D norm = QVector3D::normal(a, b, c);
-    if (sm == Smooth)
-    {
+
+    if (sm == Smooth) {
         addTri(a, b, c, norm);
         addTri(a, c, d, norm);
-    }
-    else
-    {
-        // If faceted share the two common verts
+    } else {
+        // If faceted share the two common vertices
         addTri(a, b, c, norm);
         int k = geom->vertices.count();
         geom->appendSmooth(a, norm, k);
@@ -224,9 +220,9 @@ void Patch::addQuad(const QVector3D &a, const QVector3D &b,  const QVector3D &c,
     }
 }
 
-static inline QVector<QVector3D> extrude(const QVector<QVector3D> &verts, qreal depth)
+static inline QVector<QVector3D> extrude(const QVector<QVector3D> &vertices, qreal depth)
 {
-    QVector<QVector3D> extr = verts;
+    QVector<QVector3D> extr = vertices;
     for (int v = 0; v < extr.count(); ++v)
         extr[v].setZ(extr[v].z() - depth);
     return extr;
@@ -240,6 +236,7 @@ public:
         for (int i = 0; i < parts.count(); ++i)
             parts[i]->translate(t);
     }
+
     void rotate(qreal deg, QVector3D axis)
     {
         for (int i = 0; i < parts.count(); ++i)
@@ -248,7 +245,7 @@ public:
 
     // No special Rectoid destructor - the parts are fetched out of this member
     // variable, and destroyed by the new owner
-    QList<Patch*> parts;
+    QList<Patch *> parts;
 };
 
 class RectPrism : public Rectoid