commit c40228e6fc111f23b96cfb0be7672e47b64e9168
author Colin Blundell <blundell@chromium.org> Tue Jul 23 17:55:43 2024 +0000
committer Dawn LUCI CQ <dawn-scoped@luci-project-accounts.iam.gserviceaccount.com> Tue Jul 23 17:55:43 2024 +0000
tree 6644797e239437992c3fe492d42105d6b4f5c75a
parent 1a3101b8d08da69ebf7f9496b988423522e6735e

[Vulkan] Properly handle combined image samplers

We currently set YCbCr sampler entries as COMBINED_IMAGE_SAMPLER at the
Vulkan level, but we don't actually then handle that within the Vulkan
backend:

* There should be no entry in the VkDescriptorSetLayout for the texture
  that will be paired with this sampler
* That texture should be bound in the VkDescriptorSet at the index for
  the sampler
* Within the SPIR-V, the texture var should be decorated to point at the
  binding for the combined image sampler

This CL fills in those holes. To do so, we add an optional field to
StaticSamplerBindingLayout wherein the client can specify a texture
entry that should be paired with this sampler. If that field is set, we
will create the sampler entry as COMBINED_IMAGE_SAMPLER with all that
that entails.

Followup will add validation and testing. In addition to general testing
and validation, we will validate and test the following with respect to
YCbCr samplers in particular:

* The client *must* pass the index of the texture being sampled by a
YCbCr sampler entry as part of the YCbCr sampler entry itself, in
essence requiring that the client pair YCbCr samplers and sampled
textures. This requirement matches the current Skia BGL structure and
seems like a rational restriction, as both the YCbCr sampler and the
texture being sampled by that sampler need to take their YCbCr info from
the AHB that is backing by the texture.

Change-Id: I1741f4bcf90a461a3636fd37745a80b461365006
Bug: 41488897
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/197475
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Colin Blundell <blundell@chromium.org>