Fixes a validation issue.
The issue is that the function gets called before we've sumitted a frame
for decoding to that context. However, we cannot run queries before
they've been reset, which happens at submission time.
As we'd need to otherwise run a command queue at init-time, just check
if submissions have happened.
The loader ensures only that functions with tagged supported extensions
exist, rather than ensuring only those with supported extensions are
loaded.
As the init function uses Vulkan functions, whose loading requires them
to have the extension flags set, the extension flags are guaranteed
to also exist at this point.
This reduces memory needed dramatically, as unneeded resources
can be immediately returned to the pool.
Although waitforfences is threadsafe, we add a mutex wait around
it, as the mutex fence in combination with waitforfences assures
us that no other thread will reset the fence in the meanwhile
whilst the mutex is locked. This allows is to call
ff_vk_exec_discard_deps.
This commit rewrites the majority of vulkan.c to enable its use
as a general-purpose high-level utility code, usable for decoding,
encoding, and filtering of video frames.
The dependency system was rewritten to simplify management of
execution.
The image handling system was rewritten to accomodate multiplane
images.
Due to how related all the new features were, this is a single
commit.
What happens on startup is that ffmpeg.c initializes the filter,
then frees it without feeding a single frame through. With no
input frame, the filter lacks a hardware device. The rest of the
uninit code checks if Vulkan objects exist, which they must if there's
a hardware device, but vk->DeviceWaitIdle does not require an object.
So, add a check for it.
It's got a much better API that's actually maintained, it eliminates
race conditions, it comes with a pkg-config file by default, and
unfortunately isn't currently packaged by Debian or other large
distributions.
The issue is that libavfilter depends on libavcodec, and when doing a
static build, if libavcodec also includes "libavfilter/vulkan.c", then
during link-time, compiling programs will fail as there would be multiple
definitions of the same symbols in both libavfilter and libavcodec's
object files.
Linkers are, however, more permitting if both files that include
a common file that's used as a template are one-to-one identical.
Hence, to make both files the same in the future, export all avfilter
specific functions to a separate file.
There is some work in progress to make templated files like this be
compiled only once, so this is not a long-term solution.
This also removes a macro that could be used to toggle SPIRV compilation
capability on #include-time, as this could cause the files to be different.
