mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2025-02-17 03:35:21 +00:00
qt: perform surface creation in the main thread
As is required when creating a QWindow instance set out in the Qt documentation. Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/merge_requests/575>
This commit is contained in:
Matthew Waters
parent
3ae1bae2a3
commit
05108c2898
2 changed files with 178 additions and 37 deletions
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@ -104,13 +104,25 @@ void GstAnimationDriver::setNextTime(qint64 ms)
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m_next = ms;
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}
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typedef enum
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{
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STATE_ERROR = -1,
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STATE_NEW = 0,
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STATE_WAITING_FOR_WINDOW,
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STATE_WINDOW_CREATED,
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STATE_READY,
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} SharedRenderDataState;
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struct SharedRenderData
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{
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volatile int refcount;
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SharedRenderDataState state;
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GMutex lock;
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GCond cond;
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GstAnimationDriver *m_animationDriver;
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QOpenGLContext *m_context;
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GstBackingSurface *m_surface;
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QThread *m_renderThread;
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};
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static struct SharedRenderData *
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@ -205,18 +217,78 @@ GstQuickRenderer::GstQuickRenderer()
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gl_mem(NULL),
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m_sharedRenderData(NULL)
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{
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init_debug ();
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init_debug ();
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}
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static gpointer
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dup_shared_render_data (gpointer data, gpointer user_data)
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{
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struct SharedRenderData *render_data = (struct SharedRenderData *) data;
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struct SharedRenderData *render_data = (struct SharedRenderData *) data;
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if (render_data)
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return shared_render_data_ref (render_data);
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if (render_data)
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return shared_render_data_ref (render_data);
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return NULL;
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return NULL;
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}
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class CreateSurfaceEvent : public QEvent
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{
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public:
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CreateSurfaceEvent (CreateSurfaceWorker * worker)
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: QEvent(CreateSurfaceEvent::type())
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{
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m_worker = worker;
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}
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~CreateSurfaceEvent()
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{
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GST_TRACE ("%p destroying create surface event", this);
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delete m_worker;
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}
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static QEvent::Type type()
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{
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if (customEventType == QEvent::None) {
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int generatedType = QEvent::registerEventType();
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customEventType = static_cast<QEvent::Type>(generatedType);
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}
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return customEventType;
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}
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private:
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static QEvent::Type customEventType;
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CreateSurfaceWorker *m_worker;
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};
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QEvent::Type CreateSurfaceEvent::customEventType = QEvent::None;
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CreateSurfaceWorker::CreateSurfaceWorker (struct SharedRenderData * rdata)
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{
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m_sharedRenderData = shared_render_data_ref (rdata);
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}
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CreateSurfaceWorker::~CreateSurfaceWorker ()
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{
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shared_render_data_unref (m_sharedRenderData);
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}
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bool CreateSurfaceWorker::event(QEvent * ev)
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{
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if (ev->type() == CreateSurfaceEvent::type()) {
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GST_TRACE ("%p creating surface", m_sharedRenderData);
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/* create the window surface in the main thread */
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g_mutex_lock (&m_sharedRenderData->lock);
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m_sharedRenderData->m_surface = new GstBackingSurface;
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m_sharedRenderData->m_surface->create();
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m_sharedRenderData->m_surface->moveToThread (m_sharedRenderData->m_renderThread);
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GST_TRACE ("%p created surface %p", m_sharedRenderData,
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m_sharedRenderData->m_surface);
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g_cond_broadcast (&m_sharedRenderData->cond);
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g_mutex_unlock (&m_sharedRenderData->lock);
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}
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return QObject::event(ev);
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}
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bool GstQuickRenderer::init (GstGLContext * context, GError ** error)
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@ -232,7 +304,6 @@ bool GstQuickRenderer::init (GstGLContext * context, GError ** error)
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"native context");
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return false;
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}
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QThread *renderThread = QThread::currentThread();
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struct SharedRenderData *render_data = NULL, *old_render_data;
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do {
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@ -249,46 +320,101 @@ bool GstQuickRenderer::init (GstGLContext * context, GError ** error)
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"qt.gl.render.shared.data", old_render_data, render_data,
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NULL, NULL));
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m_sharedRenderData = render_data;
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GST_TRACE ("%p retrieved shared render data %p", this, m_sharedRenderData);
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g_mutex_lock (&m_sharedRenderData->lock);
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if (!m_sharedRenderData->m_context) {
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m_sharedRenderData->m_context = new QOpenGLContext;
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GST_TRACE ("%p new QOpenGLContext %p", this, m_sharedRenderData->m_context);
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m_sharedRenderData->m_context->setNativeHandle(qt_native_context);
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if (m_sharedRenderData->state == STATE_ERROR) {
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g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_NOT_FOUND,
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"In an error state from a previous attempt");
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g_mutex_unlock (&m_sharedRenderData->lock);
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return false;
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}
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m_sharedRenderData->m_surface = new GstBackingSurface;
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m_sharedRenderData->m_surface->create(); /* FIXME: may need to be called on Qt's main thread */
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if (m_sharedRenderData->state != STATE_READY) {
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/* this state handling and locking is so that two qtglrenderer's will
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* not attempt to create an OpenGL context without freeing the previous
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* OpenGL context and cause a leak. It also only allows one
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* CreateSurfaceEvent() to be posted to the main thread
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* (QCoreApplication::instance()->thread()) while still allowing
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* multiple waiters to wait for the window to be created */
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if (m_sharedRenderData->state == STATE_NEW) {
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QCoreApplication *app = QCoreApplication::instance ();
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gst_gl_context_activate (context, FALSE);
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if (!app) {
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g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_NOT_FOUND,
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"Could not retrieve QCoreApplication instance");
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m_sharedRenderData->state = STATE_ERROR;
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g_mutex_unlock (&m_sharedRenderData->lock);
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return false;
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}
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/* Qt does some things that it may require the OpenGL context current in
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* ->create() so that it has the necessry information to create the
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* QOpenGLContext from the native handle. This may fail if the OpenGL
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* context is already current in another thread so we need to deactivate
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* the context from GStreamer's thread before asking Qt to create the
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* QOpenGLContext with ->create().
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*/
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m_sharedRenderData->m_context->create();
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m_sharedRenderData->m_context->doneCurrent();
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m_sharedRenderData->m_renderThread = QThread::currentThread();
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m_sharedRenderData->m_context = new QOpenGLContext;
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GST_TRACE ("%p new QOpenGLContext %p", this, m_sharedRenderData->m_context);
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m_sharedRenderData->m_context->setNativeHandle(qt_native_context);
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m_sharedRenderData->m_context->moveToThread (renderThread);
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if (!m_sharedRenderData->m_context->makeCurrent(m_sharedRenderData->m_surface)) {
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g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_NOT_FOUND,
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"Could not make Qt OpenGL context current");
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/* try to keep the same OpenGL context state */
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gst_gl_context_activate (context, TRUE);
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g_mutex_unlock (&m_sharedRenderData->lock);
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return false;
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CreateSurfaceWorker *w = new CreateSurfaceWorker (m_sharedRenderData);
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GST_TRACE ("%p posting create surface event to main thread with "
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"worker %p", this, w);
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w->moveToThread (app->thread());
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app->postEvent (w, new CreateSurfaceEvent (w));
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m_sharedRenderData->state = STATE_WAITING_FOR_WINDOW;
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}
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if (!gst_gl_context_activate (context, TRUE)) {
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g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_NOT_FOUND,
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"Could not make OpenGL context current again");
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g_mutex_unlock (&m_sharedRenderData->lock);
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return false;
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if (m_sharedRenderData->state == STATE_WAITING_FOR_WINDOW) {
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gint64 end_time = g_get_monotonic_time () + 5 * G_TIME_SPAN_SECOND;
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while (!m_sharedRenderData->m_surface) {
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/* XXX: This might deadlock with the main thread if the
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* QCoreApplication is not running and will not be able to
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* execute. We only wait for 5 seconds until a better
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* approach can be found here */
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if (!g_cond_wait_until (&m_sharedRenderData->cond,
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&m_sharedRenderData->lock, end_time)) {
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g_set_error (error, GST_RESOURCE_ERROR,
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GST_RESOURCE_ERROR_NOT_FOUND,
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"Could not create Qt window within 5 seconds");
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m_sharedRenderData->state = STATE_ERROR;
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g_mutex_unlock (&m_sharedRenderData->lock);
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return false;
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}
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}
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GST_TRACE ("%p surface successfully created", this);
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m_sharedRenderData->state = STATE_WINDOW_CREATED;
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}
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if (m_sharedRenderData->state == STATE_WINDOW_CREATED) {
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/* Qt does some things that may require the OpenGL context current
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* in ->create() so that it has the necessry information to create
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* the QOpenGLContext from the native handle. This may fail if the
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* OpenGL context is already current in another thread so we need
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* to deactivate the context from GStreamer's thread before asking
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* Qt to create the QOpenGLContext with ->create().
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*/
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gst_gl_context_activate (context, FALSE);
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m_sharedRenderData->m_context->create();
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m_sharedRenderData->m_context->doneCurrent();
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if (!m_sharedRenderData->m_context->makeCurrent(m_sharedRenderData->m_surface)) {
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g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_NOT_FOUND,
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"Could not make Qt OpenGL context current");
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/* try to keep the same OpenGL context state */
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gst_gl_context_activate (context, TRUE);
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m_sharedRenderData->state = STATE_ERROR;
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g_mutex_unlock (&m_sharedRenderData->lock);
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return false;
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}
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if (!gst_gl_context_activate (context, TRUE)) {
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g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_NOT_FOUND,
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"Could not make OpenGL context current again");
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m_sharedRenderData->state = STATE_ERROR;
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g_mutex_unlock (&m_sharedRenderData->lock);
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return false;
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}
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m_sharedRenderData->state = STATE_READY;
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}
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}
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g_mutex_unlock (&m_sharedRenderData->lock);
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m_renderControl = new QQuickRenderControl();
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/* Create a QQuickWindow that is associated with our render control. Note that this
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@ -297,7 +423,8 @@ bool GstQuickRenderer::init (GstGLContext * context, GError ** error)
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*/
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m_quickWindow = new QQuickWindow(m_renderControl);
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/* after QQuickWindow creation as QQuickRenderControl requires it */
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m_renderControl->prepareThread (renderThread);
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m_renderControl->prepareThread (m_sharedRenderData->m_renderThread);
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g_mutex_unlock (&m_sharedRenderData->lock);
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/* Create a QML engine. */
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m_qmlEngine = new QQmlEngine;
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@ -106,4 +106,18 @@ private:
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struct SharedRenderData *m_sharedRenderData;
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};
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class CreateSurfaceWorker : public QObject
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{
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Q_OBJECT
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public:
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CreateSurfaceWorker (struct SharedRenderData * rdata);
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~CreateSurfaceWorker ();
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bool event(QEvent *ev) override;
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private:
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struct SharedRenderData *m_sharedRenderData;
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};
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#endif /* __QT_QUICK_RENDER_H__ */
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