Reland "Metal: Add CommandRecordingContext"

This is a reland of 2b3975f808fd6f5afc5a52e58a3dcd5e73984b17

The previous CL failed to retain autoreleased ObjC objects which
should live longer than the autoreleasepool block. This reland fixes
the issue and adds tests for it.

Original change's description:
> Metal: Add CommandRecordingContext
>
> Introduces the idea of a CommandRecordingContext to the Metal backend,
> similar to other backends. This is a class to track which Metal encoder
> is open on the device-global pending MTLCommandBuffer.
> It will be needed to open/close encoders for lazy clearing.
>
> Bug: dawn:145
> Change-Id: Ief6b71a079d73943677d2b61382d1c36b88a4f87
> Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/14780
> Reviewed-by: Corentin Wallez <cwallez@chromium.org>
> Reviewed-by: Kai Ninomiya <kainino@chromium.org>
> Commit-Queue: Austin Eng <enga@chromium.org>

Bug: dawn:145
Change-Id: I67494b35225ce8f6443a3fa9787d054522e5d422
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/15042
Commit-Queue: Austin Eng <enga@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
9 files changed
tree: 795d179b999924367d1a0e9a1ae39f8589740f5f
  1. build_overrides/
  2. docs/
  3. examples/
  4. generator/
  5. infra/
  6. scripts/
  7. src/
  8. third_party/
  9. .clang-format
  10. .gitattributes
  11. .gitignore
  12. .gn
  13. AUTHORS
  14. BUILD.gn
  15. codereview.settings
  16. CONTRIBUTING.md
  17. dawn.json
  18. dawn_wire.json
  19. DEPS
  20. LICENSE
  21. OWNERS
  22. PRESUBMIT.py
  23. README.chromium
  24. README.md
README.md

Dawn, a WebGPU implementation

Dawn is an open-source and cross-platform implementation of the work-in-progress WebGPU standard. More precisely it implements webgpu.h that is a one-to-one mapping with the WebGPU IDL. Dawn is meant to be integrated as part of a larger system and is the underlying implementation of WebGPU in Chromium.

Dawn provides several WebGPU building blocks:

  • WebGPU C/C++ headers that applications and other building blocks use.
    • The webgpu.h version that Dawn implements.
    • A C++ wrapper for the webgpu.h.
  • A “native” implementation of WebGPU using platforms' GPU APIs:
    • D3D12 on Windows 10
    • Metal on macOS and iOS
    • Vulkan on Windows, Linux, ChromeOS, Android and Fuchsia
    • OpenGL as best effort where available
  • A client-server implementation of WebGPU for applications that are in a sandbox without access to native drivers

Helpful links:

Documentation table of content

Developer documentation:

User documentation: (TODO, figure out what overlaps with webgpu.h docs)

Status

(TODO)

License

Apache 2.0 Public License, please see LICENSE.

Disclaimer

This is not an officially supported Google product.