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VkSurfaceKHR surfaceForWindow(QWindow *window)



  • Looking through the source code it fails at
    QWindowsNativeInterface::nativeResourceForWindow: 'vkSurface' requested for null window or window without handle.

    void *QWindowsNativeInterface::nativeResourceForWindow(const QByteArray &resource, QWindow *window)
    {
        if (!window || !window->handle()) {
            qWarning("%s: '%s' requested for null window or window without handle.", __FUNCTION__, resource.constData());
            return nullptr;
        }
        auto *bw = static_cast<QWindowsWindow *>(window->handle());
        int type = resourceType(resource);
        if (type == HandleType)
            return bw->handle();
        switch (window->surfaceType()) {
        case QWindow::RasterSurface:
        case QWindow::RasterGLSurface:
            if (type == GetDCType)
                return bw->getDC();
            if (type == ReleaseDCType) {
                bw->releaseDC();
                return nullptr;
            }
            break;
        case QWindow::VulkanSurface:
    #if QT_CONFIG(vulkan)
            if (type == VkSurface)
                return bw->surface(nullptr, nullptr); // returns the address of the VkSurfaceKHR, not the value, as expected
    #endif
            break;
        default:
            break;
        }
        qWarning("%s: Invalid key '%s' requested.", __FUNCTION__, resource.constData());
        return nullptr;
    }
    

    What is required for a QWindow to be properly initialized to have these values?


  • Lifetime Qt Champion

    Hi,

    You might want to share the code you are actually using so it will help spot what is going on.



  • class Test_Window : Public QWindow{
    Test_Window(){
    setSurfaceType(VulkanSurface);
    m_instance=std::make_shared<QVulkanInstance>();
    }
    
    void init(*vulkan_object object){
    //Throws error here
      object->surface = surfaceForWindow(this);
      m_instance->setVkInstance(object->instance);
      m_instance->create();
      setVulkanInstance(&*m_instance);
    }
    
    private:
    std::shared_ptr<QVulkanInstance> m_instance;
    };
    
    int main(int argc, char** argv){
    QGuiApplication app(argc,argv)
    vulkan_object obj{};
    Test_Window test_window{};
    test_window.init(vulkan_object);
    test_window.show();
    app.exec();
    }


  • It seems the QWindow::handle() is NULL, how to fix this?


  • Lifetime Qt Champion

    Do you mean winId ?

    In any case, shouldn't you use QVulkanWindow ?



  • The solution is to execute window->show() before you try and create a surface.

    Also QVulkanWindow manages a bunch of vulkan types which is... not what you want.


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