Please support VK_EXT_host_image_copy

[ShabbyX]

Description of Feature

The VK_EXT_host_image_copy extension is promoted and is now core in Vulkan 1.4. While the feature is partially required (i.e. either hostImageCopy is required, or a dedicated transfer queue), it is expected to be practically ubiquitous on UMA devices. Android requires this feature for Android 16+.

It's a pretty significant feature for texture data stream on UMA devices, and it would be great to have support for it in RenderDoc.

Environment

• Graphics API: Vulkan

[ShabbyX]

@baldurk I'd be happy to take a stab at this, provided some pointers. In particular, the functions in this extension execute on the host, not sure how renderdoc deals with that (everything I've done so far was in command buffers)

[baldurk]

Yes if you want to look into it feel free. Supporting this extension is not a priority for me so I don't know when I would implement it myself.

I'm not quite sure what you mean about how the functions don't execute in a command buffer. That doesn't change much in the implementation - it mostly makes things simpler as it means no need to track whether or not to replay due to partial command buffer replay etc. They can "just" be serialised directly.

I haven't looked at the extension but I assume it works similarly to a Map/Unmap with maybe some extra info? So I would recommend looking at how those functions are implemented - some of it may not apply due to those needing to check for changes assuming this extension doesn't also have a similar map/unmap system.

[ShabbyX]

Great thanks, sure I'll take a look. Conceptually, capturing these commands would be similar to capturing some imaginary vkMemcpy(dst, src, count), where src memory must be captured according to count, but not dst memory.