add support for vulkan

[russelltg]

use ash for the vulkan types. Requires a bit of effort to rename the ash types.

Alternative is just letting bindgen do it's thing and generate all of vulkan.h, but that feels pretty messy....

[dmtrKovalenko]

I wonder about your usecase could you please clarify how are you using a pure vulkan flag

[russelltg]

Right. My usecase is russelltg/wl-screenrec#90

I'll add some comments around that. Ideally those lifetimes would be bubbled up through the bindgen interfaces but I don't think that's possible.

[russelltg]

Added a good comment about why 'static and ran cargo fmt

[russelltg]

Weird, rustup failed?

[russelltg]

Is there interest in this? If so, what is needed to move forward?

I'd like to make a release of wl-screenrec with vulkan support and would prefer to not fork.

[dmtrKovalenko]

All the build flags are working. I’m using vulkan accelerated decoders and encoders just fine with rust ffmleg sys

[russelltg]

The issue isn't with using the vulkan encoders/decoders, it's with calling the functions/using struct definitions in hwcontext_vulkan.h, like I do in https://github.com/russelltg/wl-screenrec/pull/90/files#diff-38d46369f3ed2b03aa1e4e905b9d0af3cd8b60badbe7c250903a9b2ad58a1a49R166

[russelltg]

@dmtrKovalenko freshly rebased. Let me know if you have other thoughts on how this could be handled--I'd really like to be able to call those ffmpeg functions!

[dmtrKovalenko]

I still do not understand why do you need ffmpeg sys to be dependent on ash if you can continue working with the ash types and call the functions directly.

The av api is build around the C pointers so you can perfectly fine call aw_hw_create_device with your ash returned pointer (let me know if You need an example I have it)

[dmtrKovalenko]

Please can you give me an example of a single function call that you can not call rn?

[russelltg]

I need bindings to the AVVulkanFramesContext, which has vulkan types within it.

I could have ffmpeg-sys generate the bindings for the vulkan types itself, but ash already has good (ABI correct) bindings for all vulkan structs.

I suppose it is just a few enum/typedefs then a void* to vulkan stuff, so I guess we could maybe get away with something more minimal for the moment?

[russelltg]

Bindings to AVVulkanDeviceContext (which I don't need right now, but may eventually...) is more complex and requires access to some vulkan structs. With this PR I figured I'd allow generating bindings to all the important structs in hwcontext_vulkan.h

[russelltg]

Same with AVVkFrame

[russelltg]

In addition to the structs, I need av_vkfmt_from_pixfmt

[dmtrKovalenko]

Okay let's make the CI to pass, I'll run my test suite against this patch and if everything works alright we can merge it

[russelltg]

Ping on approving CI for this

[russelltg]

Another gentle ping on this :).

I can't publish the latest wl-screenrec release to crates.io unless I publish a fork, which I would really like to avoid...