Make QOpenGLWidget public

QOpenGLWidget is now public.

In addition Qt::WA_AlwaysStackOnTop is introduced to support the
special case of semi-transparent QOpenGLWidget or QQuickWidget on
top of regular widgets.

hellogl_es2 becomes the qopenglwidget example. This example performs
painting both via QPainter and native GL commands and has the OpenGL
widget combined with other, normal widgets.

The widget stack receives some changes when it comes to renderToTexture
widgets like QQuickWidget and QOpenGLWidget. Calling update() will now
result in a paint event, which is essential for QOpenGLWidget since we
want it to behave like a regular widget. The dirty region handling is
extended specially for such widgets due to performance reasons.
(an OpenGL content update must not result in any backingstore painting,
and is thus handled as a different kind of dirtiness)

[ChangeLog] Added QOpenGLWidget. This widget serves as a replacement for QGLWidget.

Task-number: QTBUG-36899
Task-number: QTBUG-40086
Change-Id: Ibf7f82fea99b39edfffd2fc088e7e0eadbca25cf
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>

3 files changed, 276 insertions, 0 deletions

diff --git a/tests/auto/widgets/widgets/qopenglwidget/qopenglwidget.pro b/tests/auto/widgets/widgets/qopenglwidget/qopenglwidget.pro
new file mode 100644
index 0000000000..bbc6e987af
--- /dev/null
+++ b/tests/auto/widgets/widgets/qopenglwidget/qopenglwidget.pro
@@ -0,0 +1,8 @@
+CONFIG += testcase
+CONFIG += parallel_test
+TARGET = tst_qopenglwidget
+QT += gui-private core-private testlib widgets
+
+SOURCES   += tst_qopenglwidget.cpp
+
+win32-msvc2010:contains(QT_CONFIG, angle):CONFIG += insignificant_test # QTBUG-31611
diff --git a/tests/auto/widgets/widgets/qopenglwidget/tst_qopenglwidget.cpp b/tests/auto/widgets/widgets/qopenglwidget/tst_qopenglwidget.cpp
new file mode 100644
index 0000000000..14d06e7111
--- /dev/null
+++ b/tests/auto/widgets/widgets/qopenglwidget/tst_qopenglwidget.cpp
@@ -0,0 +1,266 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtWidgets/QOpenGLWidget>
+#include <QtGui/QOpenGLFunctions>
+#include <QtGui/QPainter>
+#include <QtTest/QtTest>
+#include <QSignalSpy>
+
+class tst_QOpenGLWidget : public QObject
+{
+    Q_OBJECT
+
+private slots:
+    void create();
+    void clearAndGrab();
+    void clearAndResizeAndGrab();
+    void createNonTopLevel();
+    void painter();
+    void reparentToAlreadyCreated();
+    void reparentToNotYetCreated();
+};
+
+void tst_QOpenGLWidget::create()
+{
+    QScopedPointer<QOpenGLWidget> w(new QOpenGLWidget);
+    QVERIFY(!w->isValid());
+    QSignalSpy frameSwappedSpy(w.data(), SIGNAL(frameSwapped()));
+    w->show();
+    QTest::qWaitForWindowExposed(w.data());
+    QVERIFY(frameSwappedSpy.count() > 0);
+
+    QVERIFY(w->isValid());
+    QVERIFY(w->context());
+    QVERIFY(w->context()->format() == w->format());
+    QVERIFY(w->defaultFramebufferObject() != 0);
+}
+
+class ClearWidget : public QOpenGLWidget, protected QOpenGLFunctions
+{
+public:
+    ClearWidget(QWidget *parent, int expectedWidth, int expectedHeight)
+        : QOpenGLWidget(parent),
+          m_initCalled(false), m_paintCalled(false), m_resizeCalled(false),
+          m_resizeOk(false),
+          m_w(expectedWidth), m_h(expectedHeight) { }
+
+    void initializeGL() Q_DECL_OVERRIDE {
+        m_initCalled = true;
+        initializeOpenGLFunctions();
+    }
+    void paintGL() Q_DECL_OVERRIDE {
+        m_paintCalled = true;
+        glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
+        glClear(GL_COLOR_BUFFER_BIT);
+    }
+    void resizeGL(int w, int h) Q_DECL_OVERRIDE {
+        m_resizeCalled = true;
+        m_resizeOk = w == m_w && h == m_h;
+    }
+
+    bool m_initCalled;
+    bool m_paintCalled;
+    bool m_resizeCalled;
+    bool m_resizeOk;
+    int m_w;
+    int m_h;
+};
+
+void tst_QOpenGLWidget::clearAndGrab()
+{
+    QScopedPointer<ClearWidget> w(new ClearWidget(0, 800, 600));
+    w->resize(800, 600);
+    w->show();
+    QTest::qWaitForWindowExposed(w.data());
+    QVERIFY(w->m_initCalled);
+    QVERIFY(w->m_resizeCalled);
+    QVERIFY(w->m_resizeOk);
+    QVERIFY(w->m_paintCalled);
+
+    QImage image = w->grabFramebuffer();
+    QVERIFY(!image.isNull());
+    QCOMPARE(image.width(), w->width());
+    QCOMPARE(image.height(), w->height());
+    QVERIFY(image.pixel(30, 40) == qRgb(255, 0, 0));
+}
+
+void tst_QOpenGLWidget::clearAndResizeAndGrab()
+{
+    QScopedPointer<QOpenGLWidget> w(new ClearWidget(0, 640, 480));
+    w->resize(640, 480);
+    w->show();
+    QTest::qWaitForWindowExposed(w.data());
+
+    QImage image = w->grabFramebuffer();
+    QVERIFY(!image.isNull());
+    QCOMPARE(image.width(), w->width());
+    QCOMPARE(image.height(), w->height());
+    w->resize(800, 600);
+    image = w->grabFramebuffer();
+    QVERIFY(!image.isNull());
+    QCOMPARE(image.width(), 800);
+    QCOMPARE(image.height(), 600);
+    QCOMPARE(image.width(), w->width());
+    QCOMPARE(image.height(), w->height());
+    QVERIFY(image.pixel(30, 40) == qRgb(255, 0, 0));
+}
+
+void tst_QOpenGLWidget::createNonTopLevel()
+{
+    QWidget w;
+    ClearWidget *glw = new ClearWidget(&w, 600, 700);
+    QSignalSpy frameSwappedSpy(glw, SIGNAL(frameSwapped()));
+    w.resize(400, 400);
+    w.show();
+    QTest::qWaitForWindowExposed(&w);
+    QVERIFY(frameSwappedSpy.count() > 0);
+
+    QVERIFY(glw->m_resizeCalled);
+    glw->m_resizeCalled = false;
+    QVERIFY(!glw->m_resizeOk);
+    glw->resize(600, 700);
+
+    QVERIFY(glw->m_initCalled);
+    QVERIFY(glw->m_resizeCalled);
+    QVERIFY(glw->m_resizeOk);
+    QVERIFY(glw->m_paintCalled);
+
+    QImage image = glw->grabFramebuffer();
+    QVERIFY(!image.isNull());
+    QCOMPARE(image.width(), glw->width());
+    QCOMPARE(image.height(), glw->height());
+    QVERIFY(image.pixel(30, 40) == qRgb(255, 0, 0));
+
+    glw->doneCurrent();
+    QVERIFY(!QOpenGLContext::currentContext());
+    glw->makeCurrent();
+    QVERIFY(QOpenGLContext::currentContext() == glw->context() && glw->context());
+}
+
+class PainterWidget : public QOpenGLWidget, protected QOpenGLFunctions
+{
+public:
+    PainterWidget(QWidget *parent)
+        : QOpenGLWidget(parent), m_clear(false) { }
+
+    void initializeGL() Q_DECL_OVERRIDE {
+        initializeOpenGLFunctions();
+    }
+    void paintGL() Q_DECL_OVERRIDE {
+        QPainter p(this);
+        QCOMPARE(p.device()->width(), width());
+        QCOMPARE(p.device()->height(), height());
+        p.fillRect(QRect(QPoint(0, 0), QSize(width(), height())), Qt::blue);
+        if (m_clear) {
+            p.beginNativePainting();
+            glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
+            glClear(GL_COLOR_BUFFER_BIT);
+            p.endNativePainting();
+        }
+    }
+    bool m_clear;
+};
+
+void tst_QOpenGLWidget::painter()
+{
+    QWidget w;
+    PainterWidget *glw = new PainterWidget(&w);
+    w.resize(640, 480);
+    glw->resize(320, 200);
+    w.show();
+    QTest::qWaitForWindowExposed(&w);
+
+    QImage image = glw->grabFramebuffer();
+    QCOMPARE(image.width(), glw->width());
+    QCOMPARE(image.height(), glw->height());
+    QVERIFY(image.pixel(20, 10) == qRgb(0, 0, 255));
+
+    glw->m_clear = true;
+    image = glw->grabFramebuffer();
+    QVERIFY(image.pixel(20, 10) == qRgb(0, 255, 0));
+}
+
+void tst_QOpenGLWidget::reparentToAlreadyCreated()
+{
+    QWidget w1;
+    PainterWidget *glw = new PainterWidget(&w1);
+    w1.resize(640, 480);
+    glw->resize(320, 200);
+    w1.show();
+    QTest::qWaitForWindowExposed(&w1);
+
+    QWidget w2;
+    w2.show();
+    QTest::qWaitForWindowExposed(&w2);
+
+    glw->setParent(&w2);
+    glw->show();
+
+    QImage image = glw->grabFramebuffer();
+    QCOMPARE(image.width(), 320);
+    QCOMPARE(image.height(), 200);
+    QVERIFY(image.pixel(20, 10) == qRgb(0, 0, 255));
+}
+
+void tst_QOpenGLWidget::reparentToNotYetCreated()
+{
+    QWidget w1;
+    PainterWidget *glw = new PainterWidget(&w1);
+    w1.resize(640, 480);
+    glw->resize(320, 200);
+    w1.show();
+    QTest::qWaitForWindowExposed(&w1);
+
+    QWidget w2;
+    glw->setParent(&w2);
+    w2.show();
+    QTest::qWaitForWindowExposed(&w2);
+
+    QImage image = glw->grabFramebuffer();
+    QCOMPARE(image.width(), 320);
+    QCOMPARE(image.height(), 200);
+    QVERIFY(image.pixel(20, 10) == qRgb(0, 0, 255));
+}
+
+QTEST_MAIN(tst_QOpenGLWidget)
+
+#include "tst_qopenglwidget.moc"
diff --git a/tests/auto/widgets/widgets/widgets.pro b/tests/auto/widgets/widgets/widgets.pro
index 29d1f7746c..423b3952d4 100644
--- a/tests/auto/widgets/widgets/widgets.pro
+++ b/tests/auto/widgets/widgets/widgets.pro
@@ -52,3 +52,5 @@ SUBDIRS=\
            qmainwindow \
            qtextedit \
            qtoolbar \
+
+contains(QT_CONFIG, opengl): SUBDIRS += qopenglwidget