How to Prevent VkDevice Destruction on minimize in QVulkanWindow?

[decastyle]

Problem:
I’m building a progressive ray tracer with renderer using QVulkanWindow and a custom QVulkanWindowRenderer. My ray tracer dispatches compute pipeline (vkCmdDispatch) to an output image, which I copy to a renderer-owned texture (renderImage) for display on a full-screen quad after each sample. This works fine when the window is visible. However, when I minimize the window, releaseResources() is called, and the VkDevice (managed by QVulkanWindow) is destroyed (or becomes invalid), breaking compute loop in the background. I want the VkDevice to persist across minimization so ray tracing can continue and update the display when the window is restored.

Details:

• Setup: The renderer copies the compute output to renderImage using vkCmdCopyImage and renders it with a graphics pipeline
• Current Behavior: On minimize, releaseResources() triggers, and if I clean up the compute pipeline there, background dispatching stops. If I don’t clean it up, I risk validation errors or crashes (e.g., vkFreeMemory on invalid VkDeviceMemory handles) when the window is maximized, suggesting the VkDevice is recreated by QVulkanWindow.
• Goal: prevent destruction of VkDevice when minimized, so I can dispatch compute work in a background thread and resume rendering seamlessly on maximize.

What I’ve Tried:

• Moving resource cleanup to releaseResources() stops background work.
• Using a separate VkDevice for compute avoids this but breaks vkCmdCopyImage (different devices), requiring host-staged transfers, which I’d like to avoid for performance.

Question:
How can I override or customize QVulkanWindow’s VkDevice destruction logic to keep it alive during minimization? Is there a way to manage the device lifecycle? Alternatively, how can I detect and recover from device recreation without disrupting persistent compute resources?

Context:

• Qt 6.8.1, Windows, NVIDIA GPU.
• Vulkan 1.3 (Vulkan SDK 1.4.304.0).

Any guidance or examples would be appreciated!

[SGaist]

Hi,

It's a bit a shot in the dark since I haven't used that class yet but would the PersistentResources flag do what you want ?

[decastyle]

Thank you a lot! I overlooked this flag initially.

For anyone else encountering this issue, just add this after Vulkan window creation

vulkanWindow->setFlags(QVulkanWindow::PersistentResources);