Render the widgets view using the scene graph into a QOpenGLWidget

This means that widgets application now need to setup the GL context
sharing as well. QWebEngineWidgets::initialize() must be called,
which has the same effect as QWebEngine::initialize().
The QtWebEngineWidgets now depends on the QtWebEngine module to make
this happen.

Since QOpenGLWidget is only available in Qt 5.3, this patch also
disables the webenginewidgets module completely when building using
Qt 5.2.

Change-Id: I0e99a779d1eb080f2ccf5a338ff0763ad64e6eba
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

6 files changed, 121 insertions, 37 deletions

diff --git a/src/webenginewidgets/api/qtwebenginewidgetsglobal.cpp b/src/webenginewidgets/api/qtwebenginewidgetsglobal.cpp
new file mode 100644
index 000000000..f3792248e
--- /dev/null
+++ b/src/webenginewidgets/api/qtwebenginewidgetsglobal.cpp
@@ -0,0 +1,49 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtWebEngine module 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 "qtwebenginewidgetsglobal.h"
+
+#include "qtwebengineglobal.h"
+
+void QWebEngineWidgets::initialize()
+{
+    QWebEngine::initialize();
+}
diff --git a/src/webenginewidgets/api/qtwebenginewidgetsglobal.h b/src/webenginewidgets/api/qtwebenginewidgetsglobal.h
index d875c1cbe..1836de357 100644
--- a/src/webenginewidgets/api/qtwebenginewidgetsglobal.h
+++ b/src/webenginewidgets/api/qtwebenginewidgetsglobal.h
@@ -55,6 +55,12 @@ QT_BEGIN_NAMESPACE
 #  define QWEBENGINEWIDGETS_EXPORT
 #endif
 
+class QWEBENGINEWIDGETS_EXPORT QWebEngineWidgets
+{
+public:
+    static void initialize();
+};
+
 QT_END_NAMESPACE
 
 #endif // QTWEBENGINEWIDGETSGLOBAL_H
diff --git a/src/webenginewidgets/api/qwebenginepage.cpp b/src/webenginewidgets/api/qwebenginepage.cpp
index a5e5f8320..a879a94ef 100644
--- a/src/webenginewidgets/api/qwebenginepage.cpp
+++ b/src/webenginewidgets/api/qwebenginepage.cpp
@@ -148,7 +148,7 @@ void CallbackDirectory::CallbackSharedDataPointer::doDeref()
 
 QWebEnginePagePrivate::QWebEnginePagePrivate()
     : QObjectPrivate(QObjectPrivateVersion)
-    , adapter(new WebContentsAdapter(SoftwareRenderingMode))
+    , adapter(new WebContentsAdapter(HardwareAccelerationMode))
     , history(new QWebEngineHistory(new QWebEngineHistoryPrivate(this)))
     , view(0)
 {
@@ -353,7 +353,7 @@ void QWebEnginePagePrivate::_q_webActionTriggered(bool checked)
 
 void QWebEnginePagePrivate::recreateFromSerializedHistory(QDataStream &input)
 {
-    QExplicitlySharedDataPointer<WebContentsAdapter> newWebContents = WebContentsAdapter::createFromSerializedNavigationHistory(input, this, WebContentsAdapterClient::SoftwareRenderingMode);
+    QExplicitlySharedDataPointer<WebContentsAdapter> newWebContents = WebContentsAdapter::createFromSerializedNavigationHistory(input, this, WebContentsAdapterClient::HardwareAccelerationMode);
     if (newWebContents) {
         adapter = newWebContents.data();
         adapter->initialize(this);
diff --git a/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp b/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp
index 71d6e235e..308735f70 100644
--- a/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp
+++ b/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp
@@ -41,19 +41,21 @@
 
 #include "render_widget_host_view_qt_delegate_widget.h"
 
-#include "qwebengineview.h"
 #include "qwebenginepage_p.h"
-#include <QtGlobal>
+#include "qwebengineview.h"
 #include <QLayout>
-#include <QResizeEvent>
-#include <QPainter>
-#include <QPaintEvent>
-#include <QWindow>
-#include <QtWidgets/QApplication>
+#include <QSGNode>
+#include <private/qsgadaptationlayer_p.h>
+#include <private/qsgcontext_p.h>
+#include <private/qsgrenderer_p.h>
+#include <private/qwidget_p.h>
 
 RenderWidgetHostViewQtDelegateWidget::RenderWidgetHostViewQtDelegateWidget(RenderWidgetHostViewQtDelegateClient *client, QWidget *parent)
-    : QWidget(parent)
+    : QOpenGLWidget(parent)
     , m_client(client)
+    , sgContext(QSGContext::createDefaultContext())
+    , sgRenderContext(new QSGRenderContext(sgContext.data()))
+    , rootNode(new QSGRootNode)
     , m_isPopup(false)
 {
     setFocusPolicy(Qt::ClickFocus);
@@ -68,7 +70,7 @@ void RenderWidgetHostViewQtDelegateWidget::initAsChild(WebContentsAdapterClient*
     QWebEnginePagePrivate *pagePrivate = static_cast<QWebEnginePagePrivate *>(container);
     if (pagePrivate->view) {
         pagePrivate->view->layout()->addWidget(this);
-        QWidget::show();
+        QOpenGLWidget::show();
     } else
         setParent(0);
 }
@@ -108,38 +110,38 @@ void RenderWidgetHostViewQtDelegateWidget::show()
     // Check if we're attached to a QWebEngineView, we don't
     // want to show anything else than popups as top-level.
     if (parent() || m_isPopup)
-        QWidget::show();
+        QOpenGLWidget::show();
 }
 
 void RenderWidgetHostViewQtDelegateWidget::hide()
 {
-    QWidget::hide();
+    QOpenGLWidget::hide();
 }
 
 bool RenderWidgetHostViewQtDelegateWidget::isVisible() const
 {
-    return QWidget::isVisible();
+    return QOpenGLWidget::isVisible();
 }
 
 QWindow* RenderWidgetHostViewQtDelegateWidget::window() const
 {
-    const QWidget* root = QWidget::window();
+    const QWidget* root = QOpenGLWidget::window();
     return root ? root->windowHandle() : 0;
 }
 
-void RenderWidgetHostViewQtDelegateWidget::update(const QRect& rect)
+void RenderWidgetHostViewQtDelegateWidget::update(const QRect&)
 {
-    QWidget::update(rect);
+    updateGL();
 }
 
 void RenderWidgetHostViewQtDelegateWidget::updateCursor(const QCursor &cursor)
 {
-    QWidget::setCursor(cursor);
+    QOpenGLWidget::setCursor(cursor);
 }
 
 void RenderWidgetHostViewQtDelegateWidget::resize(int width, int height)
 {
-    QWidget::resize(width, height);
+    QOpenGLWidget::resize(width, height);
 }
 
 void RenderWidgetHostViewQtDelegateWidget::move(const QPoint &screenPos)
@@ -153,7 +155,7 @@ void RenderWidgetHostViewQtDelegateWidget::inputMethodStateChanged(bool editorVi
     if (qApp->inputMethod()->isVisible() == editorVisible)
         return;
 
-    QWidget::setAttribute(Qt::WA_InputMethodEnabled, editorVisible);
+    QOpenGLWidget::setAttribute(Qt::WA_InputMethodEnabled, editorVisible);
     qApp->inputMethod()->update(Qt::ImQueryInput | Qt::ImEnabled | Qt::ImHints);
     qApp->inputMethod()->setVisible(editorVisible);
 }
@@ -170,25 +172,44 @@ QVariant RenderWidgetHostViewQtDelegateWidget::inputMethodQuery(Qt::InputMethodQ
 
 bool RenderWidgetHostViewQtDelegateWidget::supportsHardwareAcceleration() const
 {
-    return false;
-}
-
-void RenderWidgetHostViewQtDelegateWidget::paintEvent(QPaintEvent * event)
-{
-    QPainter painter(this);
-    m_client->fetchBackingStore();
-    m_client->paint(&painter, event->rect());
+    return true;
 }
 
 void RenderWidgetHostViewQtDelegateWidget::resizeEvent(QResizeEvent *resizeEvent)
 {
-    Q_UNUSED(resizeEvent);
+    QOpenGLWidget::resizeEvent(resizeEvent);
     m_client->notifyResize();
 }
 
 bool RenderWidgetHostViewQtDelegateWidget::event(QEvent *event)
 {
     if (!m_client->forwardEvent(event))
-        return QWidget::event(event);
+        return QOpenGLWidget::event(event);
     return true;
 }
+
+void RenderWidgetHostViewQtDelegateWidget::initializeGL()
+{
+    sgRenderContext->initialize(QOpenGLContext::currentContext());
+    sgRenderer.reset(sgRenderContext->createRenderer());
+    sgRenderer->setRootNode(rootNode.data());
+}
+
+void RenderWidgetHostViewQtDelegateWidget::paintGL()
+{
+    QSGNode *paintNode = m_client->updatePaintNode(rootNode->firstChild(), sgRenderContext.data());
+    if (paintNode != rootNode->firstChild()) {
+        delete rootNode->firstChild();
+        rootNode->appendChildNode(paintNode);
+    }
+
+    rootNode->markDirty(QSGNode::DirtyForceUpdate); // Force matrix, clip and opacity update.
+    sgRenderer->nodeChanged(rootNode.data(), QSGNode::DirtyForceUpdate); // Force render list update.
+
+    sgRenderer->setDeviceRect(size());
+    sgRenderer->setViewportRect(size());
+    sgRenderer->setProjectionMatrixToRect(QRectF(QPointF(), size()));
+    sgRenderer->setClearColor(Qt::transparent);
+
+    sgRenderContext->renderNextFrame(sgRenderer.data(), defaultFramebufferObject());
+}
diff --git a/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.h b/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.h
index 77a594d61..6a77d8321 100644
--- a/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.h
+++ b/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.h
@@ -45,15 +45,17 @@
 #include "render_widget_host_view_qt_delegate.h"
 #include "web_contents_adapter_client.h"
 
-#include <QWidget>
-
-class BackingStoreQt;
+#include <private/qopenglwidget_p.h>
 
 QT_BEGIN_NAMESPACE
+class QSGContext;
+class QSGRenderContext;
+class QSGRenderer;
+class QSGRootNode;
 class QWindow;
 QT_END_NAMESPACE
 
-class RenderWidgetHostViewQtDelegateWidget : public QWidget, public RenderWidgetHostViewQtDelegate
+class RenderWidgetHostViewQtDelegateWidget : public QOpenGLWidget, public RenderWidgetHostViewQtDelegate
 {
 public:
     RenderWidgetHostViewQtDelegateWidget(RenderWidgetHostViewQtDelegateClient *client, QWidget *parent = 0);
@@ -76,14 +78,19 @@ public:
     virtual void setTooltip(const QString &tooltip) Q_DECL_OVERRIDE;
 
 protected:
-    void paintEvent(QPaintEvent * event);
     bool event(QEvent *event);
     void resizeEvent(QResizeEvent *resizeEvent);
+    void initializeGL() Q_DECL_OVERRIDE;
+    void paintGL() Q_DECL_OVERRIDE;
 
     QVariant inputMethodQuery(Qt::InputMethodQuery query) const;
 
 private:
     RenderWidgetHostViewQtDelegateClient *m_client;
+    QScopedPointer<QSGContext> sgContext;
+    QScopedPointer<QSGRenderContext> sgRenderContext;
+    QScopedPointer<QSGRootNode> rootNode;
+    QScopedPointer<QSGRenderer> sgRenderer;
     bool m_isPopup;
 };
 
diff --git a/src/webenginewidgets/webenginewidgets.pro b/src/webenginewidgets/webenginewidgets.pro
index 182cb5500..1f2eb84b3 100644
--- a/src/webenginewidgets/webenginewidgets.pro
+++ b/src/webenginewidgets/webenginewidgets.pro
@@ -3,14 +3,15 @@ TARGET = QtWebEngineWidgets
 # For our export macros
 DEFINES += QT_BUILD_WEBENGINEWIDGETS_LIB
 
-QT += widgets network
-QT_PRIVATE += webenginecore widgets-private gui-private network-private core-private
+QT += webengine widgets network quick
+QT_PRIVATE += webenginecore widgets-private quick-private gui-private network-private core-private
 
 QMAKE_DOCS = $$PWD/doc/qtwebenginewidgets.qdocconf
 
 INCLUDEPATH += $$PWD api ../core
 
 SOURCES = \
+        api/qtwebenginewidgetsglobal.cpp \
         api/qwebenginehistory.cpp \
         api/qwebenginepage.cpp \
         api/qwebengineview.cpp\