Use of pre-recorded command buffers per frame

[kvark]

Your system information

We are trying to run Dota2/Vulkan on macOS via the new swapchain implementation of gfx-portability - gfx-rs/portability#210

Please describe your issue in as much detail as possible:

Our new approach has a limitation that any swapchain related work needs to be recorded only in ONE_TIME_SUBMIT command buffers, and the record-submit should be fully enclosed between acquiring a frame and presenting it.

Most applications we tested on work within this constraint, and we are very happy about the results. A few applications though are not compatible, and Dota2 appears to be one of them.

My question is basically: what are the command buffers you have that are re-usable and render to swapchain images? Understanding this would be helpful to us.

From technical perspective, at least on Metal, there aren't really any re-usable command buffers, and there aren't really any swapchain images outside of acquire/present time frame, so all of the non-trivial KHR_Swapchain use cases have to be worked around by a Vulkan Portability implementation.

[kvark]

It turned out that you just have more than one frame in flight. This is still compatible with gfx-portability 🎉
See gfx-rs/portability#220