-
Laszlo Agocs authored
Leave it up to the clients of QQuickRenderControl to do this, if they want it. It is usually not necessary. In the single-threaded widget world forcing deferred deletes to execute on every invalidate(), so for example from the hide event handler of QQuickWidget, is dangerous because widget apps tend to deleteLater() all sorts of widgets which can then be destroyed at unexpected times. From windowDestroyed() we continue to send the deferred deletes, just like all the render loops do. Task-number: QTBUG-42618 Task-number: QTBUG-40435 Change-Id: I8189124e2e7675361ee97bd8ba3e88b10ef193fa Reviewed-by:Gunnar Sletta <gunnar@sletta.org>
a29337be
/******************************************************************************** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).** Contact: http://www.qt-project.org/legal**** This file is part of the QtQuick module of the Qt Toolkit.**** $QT_BEGIN_LICENSE:LGPL21$** 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 or version 3 as published by the Free** Software Foundation and appearing in the file LICENSE.LGPLv21 and** LICENSE.LGPLv3 included in the packaging of this file. Please review the** following information to ensure the GNU Lesser General Public License** requirements will be met: https://www.gnu.org/licenses/lgpl.html and** 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.**** $QT_END_LICENSE$******************************************************************************/#include "qquickrendercontrol.h"#include "qquickrendercontrol_p.h"#include <QtCore/QCoreApplication>#include <QtCore/QTime>#include <QtCore/private/qabstractanimation_p.h>#include <QtGui/QOpenGLContext>#include <QtGui/private/qguiapplication_p.h>#include <qpa/qplatformintegration.h>#include <QtQml/private/qqmlglobal_p.h>#include <QtQuick/QQuickWindow>#include <QtQuick/private/qquickwindow_p.h>#include <private/qqmlprofilerservice_p.h>#include <QtCore/private/qobject_p.h>QT_BEGIN_NAMESPACEextern Q_GUI_EXPORT QImage qt_gl_read_framebuffer(const QSize &size, bool alpha_format, bool include_alpha);/*! \class QQuickRenderControl \brief The QQuickRenderControl class provides a mechanism for rendering the Qt Quick scenegraph onto an offscreen render target in a fully application-controlled manner. \since 5.4 QQuickWindow and QQuickView and their associated internal render loops render the Qt Quick scene onto a native window. In some cases, for example when integrating with 3rd party OpenGL renderers, it might be beneficial to get the scene into a texture that can then be used in arbitrary ways by the external rendering engine. QQuickRenderControl makes this possible in a hardware accelerated manner, unlike the performance-wise limited alternative of using7172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140
QQuickWindow::grabWindow()
When using a QQuickRenderControl, the QQuickWindow does not have to be shown
or even created at all. This means there will not be an underlying native
window for it. Instead, the QQuickWindow instance is associated with the
render control, using the overload of the QQuickWindow constructor, and an
OpenGL framebuffer object by calling QQuickWindow::setRenderTarget().
Management of the context and framebuffer object is up to the application. The
context that will be used by Qt Quick must be created before calling
initialize(). The creation of the framebuffer object can be deferred, see
below. Qt 5.4 introduces the ability for QOpenGLContext to adopt existing
native contexts. Together with QQuickRenderControl this makes it possible to
create a QOpenGLContext that shares with an external rendering engine's
existing context. This new QOpenGLContext can then be used to render the Qt
Quick scene into a texture that is accessible by the other engine's context
too.
Loading and instantiation of the QML components happen by using a
QQmlEngine. Once the root object is created, it will need to be parented to
the QQuickWindow's contentItem().
Applications will usually have to connect to 4 important signals:
\list
\li QQuickWindow::sceneGraphInitialized() Emitted at some point after calling
QQuickRenderControl::initialize(). Upon this signal, the application is
expected to create its framebuffer object and associate it with the
QQuickWindow.
\li QQuickWindow::sceneGraphInvalidated() When the scenegraph resources are
released, the framebuffer object can be destroyed too.
\li QQuickRenderControl::renderRequested() Indicates that the scene has to be
rendered by calling render(). After making the context current, applications
are expected to call render().
\li QQuickRenderControl::sceneChanged() Indicates that the scene has changed
meaning that, before rendering, polishing and synchronizing is also necessary.
\endlist
To send events, for example mouse or keyboard events, to the scene, use
QCoreApplication::sendEvent() with the QQuickWindow instance as the receiver.
\inmodule QtQuick
*/
QSGContext *QQuickRenderControlPrivate::sg = 0;
QQuickRenderControlPrivate::QQuickRenderControlPrivate()
: initialized(0),
window(0)
{
if (!sg) {
qAddPostRoutine(cleanup);
sg = QSGContext::createDefaultContext();
}
rc = new QSGRenderContext(sg);
}
QQuickRenderControlPrivate::~QQuickRenderControlPrivate()
{
delete rc;
}
void QQuickRenderControlPrivate::cleanup()
{
delete sg;
141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210
sg = 0;
}
QQuickRenderControl::QQuickRenderControl(QObject *parent)
: QObject(*(new QQuickRenderControlPrivate), parent)
{
}
/*!
Destroys the instance. Releases all scenegraph resources.
\sa invalidate()
*/
QQuickRenderControl::~QQuickRenderControl()
{
Q_D(QQuickRenderControl);
invalidate();
if (d->window)
QQuickWindowPrivate::get(d->window)->renderControl = 0;
}
void QQuickRenderControlPrivate::windowDestroyed()
{
if (window == 0) {
rc->invalidate();
QCoreApplication::sendPostedEvents(0, QEvent::DeferredDelete);
}
}
/*!
Initializes the scene graph resources. The context \a gl has to
be the current context.
\note Qt Quick does not take ownership of the context. It is up to the
application to destroy it after a call to invalidate() or after the
QQuickRenderControl instance is destroyed.
*/
void QQuickRenderControl::initialize(QOpenGLContext *gl)
{
Q_D(QQuickRenderControl);
if (!d->window) {
qWarning("QQuickRenderControl::initialize called with no associated window");
return;
}
if (QOpenGLContext::currentContext() != gl) {
qWarning("QQuickRenderControl::initialize called with incorrect current context");
return;
}
// It is the caller's responsiblity to make a context/surface current.
// It cannot be done here since the surface to use may not be the
// surface belonging to window. In fact window may not have a native
// window/surface at all.
d->rc->initialize(gl);
d->initialized = true;
}
/*!
This function should be called as late as possible before
sync(). In a threaded scenario, rendering can happen in parallel
with this function.
*/
void QQuickRenderControl::polishItems()
{
211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280
Q_D(QQuickRenderControl);
if (!d->window)
return;
QQuickWindowPrivate *cd = QQuickWindowPrivate::get(d->window);
cd->flushDelayedTouchEvent();
if (!d->window)
return;
cd->polishItems();
}
/*!
This function is used to synchronize the QML scene with the rendering scene
graph.
If a dedicated render thread is used, the GUI thread should be blocked for the
duration of this call.
\return \e true if the synchronization changed the scene graph.
*/
bool QQuickRenderControl::sync()
{
Q_D(QQuickRenderControl);
if (!d->window)
return false;
QQuickWindowPrivate *cd = QQuickWindowPrivate::get(d->window);
cd->syncSceneGraph();
// TODO: find out if the sync actually caused a scenegraph update.
return true;
}
/*!
Stop rendering and release resources. Requires a current context.
This is the equivalent of the cleanup operations that happen with a
real QQuickWindow when the window becomes hidden.
This function is called from the destructor. Therefore there will
typically be no need to call it directly. Pay attention however to
the fact that this requires the context, that was passed to
initialize(), to be the current one at the time of destroying the
QQuickRenderControl instance.
Once invalidate() has been called, it is possible to reuse the
QQuickRenderControl instance by calling initialize() again.
\note This function does not take
QQuickWindow::persistentSceneGraph() or
QQuickWindow::persistentOpenGLContext() into account. This means
that context-specific resources are always released.
*/
void QQuickRenderControl::invalidate()
{
Q_D(QQuickRenderControl);
if (!d->initialized)
return;
if (!d->window)
return;
QQuickWindowPrivate *cd = QQuickWindowPrivate::get(d->window);
cd->fireAboutToStop();
cd->cleanupNodesOnShutdown();
// We must invalidate since the context can potentially be destroyed by the
// application right after returning from this function. Invalidating is
// also essential to allow a subsequent initialize() to succeed.
d->rc->invalidate();
281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350
d->initialized = false;
}
/*!
Renders the scenegraph using the current context.
*/
void QQuickRenderControl::render()
{
Q_D(QQuickRenderControl);
if (!d->window)
return;
QQuickWindowPrivate *cd = QQuickWindowPrivate::get(d->window);
cd->renderSceneGraph(d->window->size());
}
/*!
\fn void QQuickRenderControl::renderRequested()
This signal is emitted when the scene graph needs to be rendered. It is not necessary to call sync().
\note Avoid triggering rendering directly when this signal is
emitted. Instead, prefer deferring it by using a timer for example. This
will lead to better performance.
*/
/*!
\fn void QQuickRenderControl::sceneChanged()
This signal is emitted when the scene graph is updated, meaning that
polishItems() and sync() needs to be called. If sync() returns
true, then render() needs to be called.
\note Avoid triggering polishing, synchronization and rendering directly
when this signal is emitted. Instead, prefer deferring it by using a timer
for example. This will lead to better performance.
*/
/*!
Grabs the contents of the scene and returns it as an image.
\note Requires the context to be current.
*/
QImage QQuickRenderControl::grab()
{
Q_D(QQuickRenderControl);
if (!d->window)
return QImage();
render();
QImage grabContent = qt_gl_read_framebuffer(d->window->size() * d->window->effectiveDevicePixelRatio(), false, false);
return grabContent;
}
void QQuickRenderControlPrivate::update()
{
Q_Q(QQuickRenderControl);
emit q->renderRequested();
}
void QQuickRenderControlPrivate::maybeUpdate()
{
Q_Q(QQuickRenderControl);
emit q->sceneChanged();
}
/*!
\fn QWindow *QQuickRenderControl::renderWindow(QPoint *offset)
351352353354355356357358359360361362363364365366367368369370371372373374375376
Reimplemented in subclasses to return the real window this render control
is rendering into.
If \a offset in non-null, it is set to the offset of the control
inside the window.
*/
/*!
Returns the real window that \a win is being rendered to, if any.
If \a offset in non-null, it is set to the offset of the rendering
inside its window.
*/
QWindow *QQuickRenderControl::renderWindowFor(QQuickWindow *win, QPoint *offset)
{
if (!win)
return 0;
QQuickRenderControl *rc = QQuickWindowPrivate::get(win)->renderControl;
if (rc)
return rc->renderWindow(offset);
return 0;
}
QT_END_NAMESPACE