commit b5879ac034aff8319e34c3645280bcf242cff6ac
author Le Hoang Quyen <lehoangquyen@chromium.org> Tue Jun 27 08:32:22 2023 +0000
committer Dawn LUCI CQ <dawn-scoped@luci-project-accounts.iam.gserviceaccount.com> Tue Jun 27 08:32:22 2023 +0000
tree 9e4ca7e9019c1efe84428cdbc133fccbc5d19dc5
parent f4e7eea7516fcd55c2190f10905fef81d898f52a

Metal: Initial implementation of MSAA render to single sampled.

This CL implements initial support for Multisampled render to single
sampled feature on Metal.
- This first version will only support one single color attachment
(plus any depth stencil attachment if any).
- Implicit multi-sampled textures are allocated internally by Dawn and
cached. It could be reused for multiple single-sampled textures of the
same size and format.
  - The implicit multi-sampled texture is deallocated when the last
  single sampled texture using it is released.
- The single-sampled texture is internally treated as resolve target for
the implicit multi-sampled texture in the render pass.
- To support LoadOp=Load, at the beginning of the render pass, the
single sampled texture will be blitted to the multi-sampled texture
using a full screen draw step. This step is implemented on front-end
layer rather than back-end specific layer. It can be reused by D3D
implementation in future patch.

Bug: dawn:1710
Change-Id: I35990b528d13bde14afd0a42cbd95b349466c370
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/135200
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Quyen Le <lehoangquyen@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>