[FFmpeg-devel] [PATCH 2/2] hwcontext_vulkan: expose the enabled device features

[Niklas Haas]

Hi, I guess you already know this but just as a reminder:

On Wed, 13 May 2020 17:53:33 +0200 (CEST), Lynne <dev at lynne.ee> wrote:
> +    vkGetPhysicalDeviceFeatures(hwctx->phys_dev, &dev_features);
> +#define COPY_FEATURE(DST, NAME) (DST).NAME = dev_features.NAME;
> +    COPY_FEATURE(hwctx->device_features, shaderImageGatherExtended)
> +    COPY_FEATURE(hwctx->device_features, shaderStorageImageExtendedFormats)
> +    COPY_FEATURE(hwctx->device_features, fragmentStoresAndAtomics)
> +    COPY_FEATURE(hwctx->device_features, vertexPipelineStoresAndAtomics)
> +    COPY_FEATURE(hwctx->device_features, shaderInt64)
> +#undef COPY_FEATURE

Enabling shaderStorageImageExtendedFormats makes no sense, because it's
specified that enabling this feature does nothing. It only exists for
informational purposes.

I realize you copied this code from libplacebo, but libplacebo had the
same issue and I removed it after verifying that it made no difference.
It seems to have been a legacy leftover from a bug in the validation
layers or something.

Rest LGTM, although note that libplacebo has switched to
VkPhysicalDeviceFeatures2KHR in the meantime, to avoid API breaks if I
decide to use extension features in the future. It's not a huge deal
since that struct is almost identical to VkPhysicalDeviceFeatures and
therefore it's trivially interoperable with you code whether you decide
to use it as well or not.