Use the QVulkanInstance without QPA

auto vkInstance = wlr_vk_renderer_get_instance(renderer()); 
auto qvkInstance = new QVulkanInstance();
qvkInstance->setVkInstance(vkInstance);

// If we can direct assignment by QVulkanInstancePrivate, then don't need create QPlatformVulkanInstance in the QVulkanInstancePrivate::::ensureVulkan 
// QVulkanInstancePrivate::get(qvkInstance)->platformInst.reset(new CustomPlatformVulkanInstance);
// If the QVulkanInstancePrivate::platformInst is null, there request create a QPlatformVulkanInstance object from QPA 
qvkInstance->create();

QQuickWindow *window;
...
auto wd = QWindowPrivate::get(window);
wd->platformWindow = new OutputWindow(); // My custom platform window, it's use the wlroots library and without the QPA.
window->setVulkanInstance(qvkInstance);

auto phdev = wlr_vk_renderer_get_phdev(renderer());
window->setGraphicsDevice(QQuickGraphicsDevice::fromPhysicalDevice(phdev));
...
auto vkImage = wlr_vk_renderer_get_current_image(renderer());
auto rt = QQuickRenderTarget::fromVulkanImage(vkImage, VK_IMAGE_LAYOUT_PREINITIALIZED, size());
window->setRenderTarget(rt);