Cleanup QtOpenGL examples

Cleanup the OpenGL examples
 - use nullptr (clang-tidy)
 - use member-initialization
 - avoid redundant checks for != nullptr when deleting a pointer

Change-Id: I3e4702690ed79e71c3e952d51ceef83b907b45b7
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

3 files changed, 6 insertions, 14 deletions

diff --git a/examples/opengl/cube/geometryengine.cpp b/examples/opengl/cube/geometryengine.cpp
index 1f9e16a935..24e014201e 100644
--- a/examples/opengl/cube/geometryengine.cpp
+++ b/examples/opengl/cube/geometryengine.cpp
@@ -174,6 +174,6 @@ void GeometryEngine::drawCubeGeometry(QOpenGLShaderProgram *program)
     program->setAttributeBuffer(texcoordLocation, GL_FLOAT, offset, 2, sizeof(VertexData));
 
     // Draw cube geometry using indices from VBO 1
-    glDrawElements(GL_TRIANGLE_STRIP, 34, GL_UNSIGNED_SHORT, 0);
+    glDrawElements(GL_TRIANGLE_STRIP, 34, GL_UNSIGNED_SHORT, nullptr);
 }
 //! [2]
diff --git a/examples/opengl/cube/mainwidget.cpp b/examples/opengl/cube/mainwidget.cpp
index 292a4245fa..558ecd1299 100644
--- a/examples/opengl/cube/mainwidget.cpp
+++ b/examples/opengl/cube/mainwidget.cpp
@@ -52,15 +52,7 @@
 
 #include <QMouseEvent>
 
-#include <math.h>
-
-MainWidget::MainWidget(QWidget *parent) :
-    QOpenGLWidget(parent),
-    geometries(0),
-    texture(0),
-    angularSpeed(0)
-{
-}
+#include <cmath>
 
 MainWidget::~MainWidget()
 {
diff --git a/examples/opengl/cube/mainwidget.h b/examples/opengl/cube/mainwidget.h
index cd2f8098ad..b6a03d454a 100644
--- a/examples/opengl/cube/mainwidget.h
+++ b/examples/opengl/cube/mainwidget.h
@@ -69,7 +69,7 @@ class MainWidget : public QOpenGLWidget, protected QOpenGLFunctions
     Q_OBJECT
 
 public:
-    explicit MainWidget(QWidget *parent = 0);
+    using QOpenGLWidget::QOpenGLWidget;
     ~MainWidget();
 
 protected:
@@ -87,15 +87,15 @@ protected:
 private:
     QBasicTimer timer;
     QOpenGLShaderProgram program;
-    GeometryEngine *geometries;
+    GeometryEngine *geometries = nullptr;
 
-    QOpenGLTexture *texture;
+    QOpenGLTexture *texture = nullptr;
 
     QMatrix4x4 projection;
 
     QVector2D mousePressPosition;
     QVector3D rotationAxis;
-    qreal angularSpeed;
+    qreal angularSpeed = 0;
     QQuaternion rotation;
 };