对于qml客户端，从c++注册QtWayland失败

Question

我的qtwayland合成器测试有一个奇怪的问题。它似乎只适用于qt c++客户端。Qml客户端以死锁结束，事件处理停止(对于客户端)。我已经更改了这个https://doc.qt.io/archives/qt-5.11/qtwaylandcompositor-qwindow-compositor-example.html示例，并添加了以下功能：

void Compositor::onSurfaceCreated(QWaylandSurface *surface)
{
    connect(surface, &QWaylandSurface::subsurfacePositionChanged, this, &WaylandInterface::onSubsurfacePositionChanged);
    QQuickWindow *window = new QQuickWindow();
    window->resize( 400, 400);
    window->setVisible(true);
    QWaylandOutput* output = new QWaylandOutput( this, window );

    QCoreApplication::processEvents();
    View *view = new View(this);
    view->setSurface(surface);
    view->setOutput(output);
    view->m_window = window;
    m_views << view;

    connect(surface, &QWaylandSurface::surfaceDestroyed, view, [view] {
        view->m_window->requestUpdate();
    } );

    connect(surface, &QWaylandSurface::hasContentChanged, this, &WaylandInterface::surfaceHasContentChanged);
    connect(surface, &QWaylandSurface::hasContentChanged, view, [view] {
        view->m_window->requestUpdate();
    } );
    connect(surface, &QWaylandSurface::redraw, view, [view] {
        view->m_window->requestUpdate();
    } );


    QWaylandQuickItem * surfacItem = new QWaylandQuickItem( view->m_window->contentItem() );
    surfacItem->setSurface( surface );
    surfacItem->setOutput( view->output() );
    surfacItem->setPaintEnabled(true);
    surfacItem->setInputEventsEnabled(true);
    connect(surface, &QWaylandSurface::offsetForNextFrame, view, &View::onOffsetForNextFrame);
    connect(view, &QWaylandView::surfaceDestroyed, this, &WaylandInterface::viewSurfaceDestroyed);
}

对于c++客户端，它创建一个窗口并将客户端嵌入其中，而qml客户端没有响应。创建窗口、输出和QuickItem的顺序是否正确？我错过了什么吗？

谢谢，凯恩

Answer 1

c++客户端使用单线程渲染，而qml客户端使用渲染线程。当一个expose事件被发送到渲染器时，qtwayland将阻止它，除非命令输出释放互斥锁。渲染器锁定帧缓冲区时，它正在等待服务器，而主线程正在等待渲染线程=>死锁。

回调可以通过output->frameStarted()；//渲染前output->sendFrameCallback()；//渲染后发送