gstreamer/ext/qt/qtglrenderer.cc

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#include <QObject>
#include <QQmlEngine>
#include <QQmlComponent>
#include <QWindow>
#include <QQuickRenderControl>
#include <QQuickWindow>
#include <QQuickItem>
#include <QOpenGLContext>
#include <QOpenGLFunctions>
#include <QOpenGLFramebufferObject>
#include <QAnimationDriver>
#include <gst/gl/gl.h>
#include <gst/gl/gstglfuncs.h>
#include "qtglrenderer.h"
#include "gstqtglutility.h"
#define GST_CAT_DEFAULT gst_qt_gl_renderer_debug
GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
static void
init_debug (void)
{
static volatile gsize _debug;
if (g_once_init_enter (&_debug)) {
GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "qtglrenderer", 0,
"Qt OpenGL Renderer");
g_once_init_leave (&_debug, 1);
}
}
/* Needs to be based on QWindow otherwise (at least) windows and nvidia
* proprietary on linux does not work
* We also need to override the size handling to get the correct output size
*/
class GstBackingSurface : public QWindow
{
public:
GstBackingSurface();
~GstBackingSurface();
void setSize (int width, int height);
QSize size() const override;
private:
QSize m_size;
};
GstBackingSurface::GstBackingSurface()
: m_size(QSize())
{
/* we do OpenGL things so need an OpenGL surface */
setSurfaceType(QSurface::OpenGLSurface);
}
GstBackingSurface::~GstBackingSurface()
{
}
QSize GstBackingSurface::size () const
{
return m_size;
}
void GstBackingSurface::setSize (int width, int height)
{
m_size = QSize (width, height);
}
class GstAnimationDriver : public QAnimationDriver
{
public:
GstAnimationDriver();
void setNextTime(qint64 ms);
void advance() override;
qint64 elapsed() const override;
private:
qint64 m_elapsed;
qint64 m_next;
};
GstAnimationDriver::GstAnimationDriver()
: m_elapsed(0),
m_next(0)
{
}
void GstAnimationDriver::advance()
{
m_elapsed = m_next;
advanceAnimation();
}
qint64 GstAnimationDriver::elapsed() const
{
return m_elapsed;
}
void GstAnimationDriver::setNextTime(qint64 ms)
{
m_next = ms;
}
typedef enum
{
STATE_ERROR = -1,
STATE_NEW = 0,
STATE_WAITING_FOR_WINDOW,
STATE_WINDOW_CREATED,
STATE_READY,
} SharedRenderDataState;
struct SharedRenderData
{
volatile int refcount;
SharedRenderDataState state;
GMutex lock;
GCond cond;
GstAnimationDriver *m_animationDriver;
QOpenGLContext *m_context;
GstBackingSurface *m_surface;
QThread *m_renderThread;
};
static struct SharedRenderData *
shared_render_data_new (void)
{
struct SharedRenderData *ret = g_new0 (struct SharedRenderData, 1);
ret->refcount = 1;
g_mutex_init (&ret->lock);
return ret;
}
static void
shared_render_data_free (struct SharedRenderData * data)
{
GST_DEBUG ("%p freeing shared render data", data);
g_mutex_clear (&data->lock);
if (data->m_animationDriver) {
data->m_animationDriver->uninstall();
delete data->m_animationDriver;
}
data->m_animationDriver = nullptr;
if (data->m_context)
delete data->m_context;
data->m_context = nullptr;
if (data->m_surface)
delete data->m_surface;
data->m_surface = nullptr;
}
static struct SharedRenderData *
shared_render_data_ref (struct SharedRenderData * data)
{
GST_TRACE ("%p reffing shared render data", data);
g_atomic_int_inc (&data->refcount);
return data;
}
static void
shared_render_data_unref (struct SharedRenderData * data)
{
GST_TRACE ("%p unreffing shared render data", data);
if (g_atomic_int_dec_and_test (&data->refcount))
shared_render_data_free (data);
}
void
GstQuickRenderer::deactivateContext ()
{
}
void
GstQuickRenderer::activateContext ()
{
}
struct FBOUserData
{
GstGLContext * context;
QOpenGLFramebufferObject * fbo;
};
static void
delete_cxx_gl_context (GstGLContext * context, struct FBOUserData * data)
{
GST_TRACE ("freeing Qfbo %p", data->fbo);
delete data->fbo;
}
static void
notify_fbo_delete (struct FBOUserData * data)
{
gst_gl_context_thread_add (data->context,
(GstGLContextThreadFunc) delete_cxx_gl_context, data);
gst_object_unref (data->context);
g_free (data);
}
GstQuickRenderer::GstQuickRenderer()
: gl_context(NULL),
m_fbo(nullptr),
m_quickWindow(nullptr),
m_renderControl(nullptr),
m_qmlEngine(nullptr),
m_qmlComponent(nullptr),
m_rootItem(nullptr),
gl_allocator(NULL),
gl_params(NULL),
gl_mem(NULL),
m_sharedRenderData(NULL)
{
init_debug ();
}
static gpointer
dup_shared_render_data (gpointer data, gpointer user_data)
{
struct SharedRenderData *render_data = (struct SharedRenderData *) data;
if (render_data)
return shared_render_data_ref (render_data);
return NULL;
}
class CreateSurfaceEvent : public QEvent
{
public:
CreateSurfaceEvent (CreateSurfaceWorker * worker)
: QEvent(CreateSurfaceEvent::type())
{
m_worker = worker;
}
~CreateSurfaceEvent()
{
GST_TRACE ("%p destroying create surface event", this);
delete m_worker;
}
static QEvent::Type type()
{
if (customEventType == QEvent::None) {
int generatedType = QEvent::registerEventType();
customEventType = static_cast<QEvent::Type>(generatedType);
}
return customEventType;
}
private:
static QEvent::Type customEventType;
CreateSurfaceWorker *m_worker;
};
QEvent::Type CreateSurfaceEvent::customEventType = QEvent::None;
CreateSurfaceWorker::CreateSurfaceWorker (struct SharedRenderData * rdata)
{
m_sharedRenderData = shared_render_data_ref (rdata);
}
CreateSurfaceWorker::~CreateSurfaceWorker ()
{
shared_render_data_unref (m_sharedRenderData);
}
bool CreateSurfaceWorker::event(QEvent * ev)
{
if (ev->type() == CreateSurfaceEvent::type()) {
GST_TRACE ("%p creating surface", m_sharedRenderData);
/* create the window surface in the main thread */
g_mutex_lock (&m_sharedRenderData->lock);
m_sharedRenderData->m_surface = new GstBackingSurface;
m_sharedRenderData->m_surface->create();
m_sharedRenderData->m_surface->moveToThread (m_sharedRenderData->m_renderThread);
GST_TRACE ("%p created surface %p", m_sharedRenderData,
m_sharedRenderData->m_surface);
g_cond_broadcast (&m_sharedRenderData->cond);
g_mutex_unlock (&m_sharedRenderData->lock);
}
return QObject::event(ev);
}
bool GstQuickRenderer::init (GstGLContext * context, GError ** error)
{
g_return_val_if_fail (GST_IS_GL_CONTEXT (context), false);
g_return_val_if_fail (gst_gl_context_get_current () == context, false);
QVariant qt_native_context = qt_opengl_native_context_from_gst_gl_context (context);
if (qt_native_context.isNull()) {
g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_NOT_FOUND,
"Could not convert from the provided GstGLContext to a Qt "
"native context");
return false;
}
struct SharedRenderData *render_data = NULL, *old_render_data;
do {
if (render_data)
shared_render_data_unref (render_data);
old_render_data = render_data = (struct SharedRenderData *)
g_object_dup_data (G_OBJECT (context),
"qt.gl.render.shared.data", dup_shared_render_data, NULL);
if (!render_data)
render_data = shared_render_data_new ();
} while (old_render_data != render_data
&& !g_object_replace_data (G_OBJECT (context),
"qt.gl.render.shared.data", old_render_data, render_data,
NULL, NULL));
m_sharedRenderData = render_data;
GST_TRACE ("%p retrieved shared render data %p", this, m_sharedRenderData);
g_mutex_lock (&m_sharedRenderData->lock);
if (m_sharedRenderData->state == STATE_ERROR) {
g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_NOT_FOUND,
"In an error state from a previous attempt");
g_mutex_unlock (&m_sharedRenderData->lock);
return false;
}
if (m_sharedRenderData->state != STATE_READY) {
/* this state handling and locking is so that two qtglrenderer's will
* not attempt to create an OpenGL context without freeing the previous
* OpenGL context and cause a leak. It also only allows one
* CreateSurfaceEvent() to be posted to the main thread
* (QCoreApplication::instance()->thread()) while still allowing
* multiple waiters to wait for the window to be created */
if (m_sharedRenderData->state == STATE_NEW) {
QCoreApplication *app = QCoreApplication::instance ();
if (!app) {
g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_NOT_FOUND,
"Could not retrieve QCoreApplication instance");
m_sharedRenderData->state = STATE_ERROR;
g_mutex_unlock (&m_sharedRenderData->lock);
return false;
}
m_sharedRenderData->m_renderThread = QThread::currentThread();
m_sharedRenderData->m_context = new QOpenGLContext;
GST_TRACE ("%p new QOpenGLContext %p", this, m_sharedRenderData->m_context);
m_sharedRenderData->m_context->setNativeHandle(qt_native_context);
CreateSurfaceWorker *w = new CreateSurfaceWorker (m_sharedRenderData);
GST_TRACE ("%p posting create surface event to main thread with "
"worker %p", this, w);
w->moveToThread (app->thread());
app->postEvent (w, new CreateSurfaceEvent (w));
m_sharedRenderData->state = STATE_WAITING_FOR_WINDOW;
}
if (m_sharedRenderData->state == STATE_WAITING_FOR_WINDOW) {
gint64 end_time = g_get_monotonic_time () + 5 * G_TIME_SPAN_SECOND;
while (!m_sharedRenderData->m_surface) {
/* XXX: This might deadlock with the main thread if the
* QCoreApplication is not running and will not be able to
* execute. We only wait for 5 seconds until a better
* approach can be found here */
if (!g_cond_wait_until (&m_sharedRenderData->cond,
&m_sharedRenderData->lock, end_time)) {
g_set_error (error, GST_RESOURCE_ERROR,
GST_RESOURCE_ERROR_NOT_FOUND,
"Could not create Qt window within 5 seconds");
m_sharedRenderData->state = STATE_ERROR;
g_mutex_unlock (&m_sharedRenderData->lock);
return false;
}
}
GST_TRACE ("%p surface successfully created", this);
m_sharedRenderData->state = STATE_WINDOW_CREATED;
}
if (m_sharedRenderData->state == STATE_WINDOW_CREATED) {
/* Qt does some things that may require the OpenGL context current
* in ->create() so that it has the necessry information to create
* the QOpenGLContext from the native handle. This may fail if the
* OpenGL context is already current in another thread so we need
* to deactivate the context from GStreamer's thread before asking
* Qt to create the QOpenGLContext with ->create().
*/
gst_gl_context_activate (context, FALSE);
m_sharedRenderData->m_context->create();
m_sharedRenderData->m_context->doneCurrent();
if (!m_sharedRenderData->m_context->makeCurrent(m_sharedRenderData->m_surface)) {
g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_NOT_FOUND,
"Could not make Qt OpenGL context current");
/* try to keep the same OpenGL context state */
gst_gl_context_activate (context, TRUE);
m_sharedRenderData->state = STATE_ERROR;
g_mutex_unlock (&m_sharedRenderData->lock);
return false;
}
if (!gst_gl_context_activate (context, TRUE)) {
g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_NOT_FOUND,
"Could not make OpenGL context current again");
m_sharedRenderData->state = STATE_ERROR;
g_mutex_unlock (&m_sharedRenderData->lock);
return false;
}
m_sharedRenderData->state = STATE_READY;
}
}
m_renderControl = new QQuickRenderControl();
/* Create a QQuickWindow that is associated with our render control. Note that this
* window never gets created or shown, meaning that it will never get an underlying
* native (platform) window.
*/
m_quickWindow = new QQuickWindow(m_renderControl);
/* after QQuickWindow creation as QQuickRenderControl requires it */
m_renderControl->prepareThread (m_sharedRenderData->m_renderThread);
g_mutex_unlock (&m_sharedRenderData->lock);
/* Create a QML engine. */
m_qmlEngine = new QQmlEngine;
if (!m_qmlEngine->incubationController())
m_qmlEngine->setIncubationController(m_quickWindow->incubationController());
gl_context = static_cast<GstGLContext*>(gst_object_ref (context));
gl_allocator = (GstGLBaseMemoryAllocator *) gst_gl_memory_allocator_get_default (gl_context);
gl_params = (GstGLAllocationParams *)
gst_gl_video_allocation_params_new_wrapped_texture (gl_context,
NULL, &this->v_info, 0, NULL, GST_GL_TEXTURE_TARGET_2D, GST_GL_RGBA8,
0, NULL, (GDestroyNotify) notify_fbo_delete);
/* This is a gross hack relying on the internals of Qt and GStreamer
* however it's the only way to remove this warning on shutdown of all
* resources.
*
* GLib-CRITICAL **: 17:35:24.988: g_main_context_pop_thread_default: assertion 'g_queue_peek_head (stack) == context' failed
*
* The reason is that libgstgl has a GMainContext that it pushes as the
* thread default context. Then later, Qt pushes a thread default main
* context. The detruction order of the GMainContext's is reversed as
* GStreamer will explicitly pop the thread default main context however
* Qt pops when the thread is about to be destroyed. GMainContext is
* unhappy with the ordering of the pops.
*/
GMainContext *gst_main_context = g_main_context_ref_thread_default ();
/* make Qt allocate and push a thread-default GMainContext if it is
* going to */
QEventLoop loop;
if (loop.processEvents())
GST_LOG ("pending QEvents processed");
GMainContext *qt_main_context = g_main_context_ref_thread_default ();
if (qt_main_context == gst_main_context) {
g_main_context_unref (qt_main_context);
g_main_context_unref (gst_main_context);
} else {
/* We flip the order of the GMainContext's so that the destruction
* order can be preserved. */
g_main_context_pop_thread_default (qt_main_context);
g_main_context_pop_thread_default (gst_main_context);
g_main_context_push_thread_default (qt_main_context);
g_main_context_push_thread_default (gst_main_context);
g_main_context_unref (qt_main_context);
g_main_context_unref (gst_main_context);
}
return true;
}
GstQuickRenderer::~GstQuickRenderer()
{
gst_gl_allocation_params_free (gl_params);
gst_clear_object (&gl_allocator);
}
void GstQuickRenderer::stopGL ()
{
GST_DEBUG ("%p stop QOpenGLContext curent: %p stored: %p", this,
QOpenGLContext::currentContext(), m_sharedRenderData->m_context);
g_assert (QOpenGLContext::currentContext() == m_sharedRenderData->m_context);
if (m_renderControl)
m_renderControl->invalidate();
if (m_fbo)
delete m_fbo;
m_fbo = nullptr;
QEventLoop loop;
if (loop.processEvents())
GST_LOG ("%p pending QEvents processed", this);
if (m_sharedRenderData)
shared_render_data_unref (m_sharedRenderData);
m_sharedRenderData = NULL;
/* XXX: reset the OpenGL context and drawable as Qt may have clobbered it.
* Fixes any attempt to access OpenGL after shutting down qmlgloverlay. */
gst_gl_context_activate (gl_context, FALSE);
gst_gl_context_activate (gl_context, TRUE);
}
void GstQuickRenderer::cleanup()
{
if (gl_context)
gst_gl_context_thread_add (gl_context,
(GstGLContextThreadFunc) GstQuickRenderer::stop_c, this);
/* Delete the render control first since it will free the scenegraph resources.
* Destroy the QQuickWindow only afterwards. */
if (m_renderControl)
delete m_renderControl;
m_renderControl = nullptr;
if (m_qmlComponent)
delete m_qmlComponent;
m_qmlComponent = nullptr;
if (m_quickWindow)
delete m_quickWindow;
m_quickWindow = nullptr;
if (m_qmlEngine)
delete m_qmlEngine;
m_qmlEngine = nullptr;
if (m_rootItem)
delete m_rootItem;
m_rootItem = nullptr;
gst_clear_object (&gl_context);
}
void GstQuickRenderer::ensureFbo()
{
if (m_fbo && m_fbo->size() != m_sharedRenderData->m_surface->size()) {
GST_INFO ("%p removing old framebuffer created with size %ix%i",
this, m_fbo->size().width(), m_fbo->size().height());
delete m_fbo;
m_fbo = nullptr;
}
if (!m_fbo) {
m_fbo = new QOpenGLFramebufferObject(m_sharedRenderData->m_surface->size(),
QOpenGLFramebufferObject::CombinedDepthStencil);
m_quickWindow->setRenderTarget(m_fbo);
GST_DEBUG ("%p new framebuffer created with size %ix%i", this,
m_fbo->size().width(), m_fbo->size().height());
}
}
void
GstQuickRenderer::renderGstGL ()
{
const GstGLFuncs *gl = gl_context->gl_vtable;
GST_TRACE ("%p current QOpenGLContext %p", this,
QOpenGLContext::currentContext());
m_quickWindow->resetOpenGLState();
m_sharedRenderData->m_animationDriver->advance();
QEventLoop loop;
if (loop.processEvents())
GST_LOG ("pending QEvents processed");
loop.exit();
ensureFbo();
/* Synchronization and rendering happens here on the render thread. */
if (m_renderControl->sync())
GST_LOG ("sync successful");
/* Meanwhile on this thread continue with the actual rendering. */
m_renderControl->render();
GST_DEBUG ("wrapping Qfbo %p with texture %u", m_fbo, m_fbo->texture());
struct FBOUserData *data = g_new0 (struct FBOUserData, 1);
data->context = (GstGLContext *) gst_object_ref (gl_context);
data->fbo = m_fbo;
gl_params->user_data = static_cast<gpointer> (data);
gl_params->gl_handle = GINT_TO_POINTER (m_fbo->texture());
gl_mem = (GstGLMemory *) gst_gl_base_memory_alloc (gl_allocator, gl_params);
m_fbo = nullptr;
m_quickWindow->resetOpenGLState ();
/* Qt doesn't seem to reset this, breaking glimagesink */
if (gl->DrawBuffer)
gl->DrawBuffer (GL_BACK);
}
GstGLMemory *GstQuickRenderer::generateOutput(GstClockTime input_ns)
{
m_sharedRenderData->m_animationDriver->setNextTime(input_ns / GST_MSECOND);
/* run an event loop to update any changed values for rendering */
QEventLoop loop;
if (loop.processEvents())
GST_LOG ("pending QEvents processed");
GST_LOG ("generating output for time %" GST_TIME_FORMAT " ms: %"
G_GUINT64_FORMAT, GST_TIME_ARGS (input_ns), input_ns / GST_MSECOND);
m_quickWindow->update();
/* Polishing happens on the gui thread. */
m_renderControl->polishItems();
/* TODO: an async version could be used where */
gst_gl_context_thread_add (gl_context,
(GstGLContextThreadFunc) GstQuickRenderer::render_gst_gl_c, this);
GstGLMemory *tmp = gl_mem;
gl_mem = NULL;
return tmp;
}
void GstQuickRenderer::initializeGstGL ()
{
GST_TRACE ("current QOpenGLContext %p", QOpenGLContext::currentContext());
if (!m_sharedRenderData->m_context->makeCurrent(m_sharedRenderData->m_surface)) {
m_errorString = "Failed to make Qt's wrapped OpenGL context current";
return;
}
GST_INFO ("current QOpenGLContext %p", QOpenGLContext::currentContext());
/* XXX: Avoid an assertion inside QSGDefaultRenderContext::initialize()
* from an unused (in this scenario) property when using multiple
* QQuickRenderControl's with the same QOpenGLContext.
*
* First noticed with Qt 5.15. Idea from:
* https://forum.qt.io/topic/55888/is-it-impossible-that-2-qquickrendercontrol-use-same-qopenglcontext/2
*
* ASSERT: "!m_gl->property(QSG_RENDERCONTEXT_PROPERTY).isValid()" in file /path/to/qt5/qtdeclarative/src/quick/scenegraph/qsgdefaultrendercontext.cpp, line 121
*/
m_sharedRenderData->m_context->setProperty("_q_sgrendercontext", QVariant());
m_renderControl->initialize(m_sharedRenderData->m_context);
/* 1. QAnimationDriver's are thread-specific
* 2. QAnimationDriver controls the 'animation time' that the Qml scene is
* rendered at
*/
/* FIXME: what happens with multiple qmlgloverlay elements? Do we need a
* shared animation driver? */
g_mutex_lock (&m_sharedRenderData->lock);
if (m_sharedRenderData->m_animationDriver == nullptr) {
m_sharedRenderData->m_animationDriver = new GstAnimationDriver;
m_sharedRenderData->m_animationDriver->install();
}
g_mutex_unlock (&m_sharedRenderData->lock);
/* XXX: reset the OpenGL context drawable as Qt may have clobbered it.
* Fixes glimagesink output where Qt replaces the Surface to use in its
* own MakeCurrent call. Qt does this on it's OpenGL initialisation
* the the rendering engine. */
gst_gl_context_activate (gl_context, FALSE);
gst_gl_context_activate (gl_context, TRUE);
}
void GstQuickRenderer::initializeQml()
{
disconnect(m_qmlComponent, &QQmlComponent::statusChanged, this,
&GstQuickRenderer::initializeQml);
if (m_qmlComponent->isError()) {
const QList<QQmlError> errorList = m_qmlComponent->errors();
for (const QQmlError &error : errorList)
m_errorString += error.toString();
return;
}
QObject *rootObject = m_qmlComponent->create();
if (m_qmlComponent->isError()) {
const QList<QQmlError> errorList = m_qmlComponent->errors();
for (const QQmlError &error : errorList)
m_errorString += error.toString();
delete rootObject;
return;
}
m_rootItem = qobject_cast<QQuickItem *>(rootObject);
if (!m_rootItem) {
m_errorString += "root QML item is not a QQuickItem";
delete rootObject;
return;
}
/* The root item is ready. Associate it with the window. */
m_rootItem->setParentItem(m_quickWindow->contentItem());
/* Update item and rendering related geometries. */
updateSizes();
/* Initialize the render control and our OpenGL resources. */
gst_gl_context_thread_add (gl_context,
(GstGLContextThreadFunc) GstQuickRenderer::initialize_gst_gl_c, this);
}
void GstQuickRenderer::updateSizes()
{
GstBackingSurface *surface =
static_cast<GstBackingSurface *>(m_sharedRenderData->m_surface);
/* Behave like SizeRootObjectToView. */
QSize size = surface->size();
m_rootItem->setWidth(size.width());
m_rootItem->setHeight(size.height());
m_quickWindow->setGeometry(0, 0, size.width(), size.height());
gst_video_info_set_format (&v_info, GST_VIDEO_FORMAT_RGBA, size.width(),
size.height());
GstGLVideoAllocationParams *params = (GstGLVideoAllocationParams *) (gl_params);
gst_video_info_set_format (params->v_info, GST_VIDEO_FORMAT_RGBA, size.width(),
size.height());
}
void GstQuickRenderer::setSize(int w, int h)
{
static_cast<GstBackingSurface *>(m_sharedRenderData->m_surface)->setSize(w, h);
updateSizes();
}
bool GstQuickRenderer::setQmlScene (const gchar * scene, GError ** error)
{
/* replacing the scene is not supported */
g_return_val_if_fail (m_qmlComponent == NULL, false);
m_errorString = "";
m_qmlComponent = new QQmlComponent(m_qmlEngine);
/* XXX: do we need to provide a propper base name? */
m_qmlComponent->setData(QByteArray (scene), QUrl(""));
if (m_qmlComponent->isLoading())
/* TODO: handle async properly */
connect(m_qmlComponent, &QQmlComponent::statusChanged, this,
&GstQuickRenderer::initializeQml);
else
initializeQml();
if (m_errorString != "") {
QByteArray string = m_errorString.toUtf8();
g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_SETTINGS,
"%s", string.constData());
return FALSE;
}
return TRUE;
}
QQuickItem * GstQuickRenderer::rootItem() const
{
return m_rootItem;
}