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//! [0]
    int main(int argc, char **argv)
    {
        QGuiApplication app(argc, argv);

        QVulkanInstance inst;
        if (!inst.create())
            return 1;

        ...
        window->setVulkanInstance(&inst);
        window->show();

        return app.exec();
    }
//! [0]

//! [1]
    QVulkanInstance inst;

    // Enable validation layer, if supported. Messages go to qDebug by default.
    inst.setLayers(QByteArrayList() << "VK_LAYER_LUNARG_standard_validation");

    bool ok = inst.create();
    if (!ok)
        ... // Vulkan not available
    if (!inst.layers().contains("VK_LAYER_LUNARG_standard_validation"))
        ... // validation layer not available
//! [1]

//! [2]
    QVulkanInstance inst;

    if (inst.supportedLayers().contains("VK_LAYER_LUNARG_standard_validation"))
        ...

    bool ok = inst.create();
    ...
//! [2]

//! [3]
    class VulkanWindow : public QWindow
    {
    public:
        VulkanWindow() {
            setSurfaceType(VulkanSurface);
        }

        void exposeEvent(QExposeEvent *) {
            if (isExposed()) {
                if (!m_initialized) {
                    m_initialized = true;
                    // initialize device, swapchain, etc.
                    QVulkanInstance *inst = vulkanInstance();
                    QVulkanFunctions *f = inst->functions();
                    uint32_t devCount = 0;
                    f->vkEnumeratePhysicalDevices(inst->vkInstance(), &devCount, nullptr);
                    ...
                    // build the first frame
                    render();
                }
            }
        }

        bool event(QEvent *e) {
            if (e->type() == QEvent::UpdateRequest)
                render();
            return QWindow::event(e);
        }

        void render() {
           ...
           requestUpdate(); // render continuously
        }

    private:
        bool m_initialized = false;
    };

    int main(int argc, char **argv)
    {
        QGuiApplication app(argc, argv);

        QVulkanInstance inst;
        if (!inst.create()) {
            qWarning("Vulkan not available");
            return 1;
        }

        VulkanWindow window;
        window.showMaximized();

        return app.exec();

    }
//! [3]
