[gl] Fix compute blit encoding for RG11B10Ufloat T2B copies

Fix kEncodeRG11B10UfloatInU32 in BlitTextureToBuffer.cpp:
- Replace log2/exp2 floating point math with IEEE 754 bitcast manipulation.
- Correctly handle NaN, Infinity, negative values (clamped to 0.0), and overflow
  clamping to maximum finite values (65024.0 for 11-bit, 64512.0 for 10-bit).
- Handle subnormals and mantissa carry into exponent correctly without
  overflowing into reserved exponent 31 (Infinity/NaN).

Add an end2end regression test cloned from CTS image_copy:mip_levels
verifying RG11B10Ufloat texture-to-buffer copies with and without the
use_blit_for_rg11b10ufloat_texture_copy toggle in OpenGLESBackend config.

Turn on UseBlitForRG11B10UfloatTextureCopy for OpenGL ES by default,
as GL_RGB / GL_UNSIGNED_INT_10F_11F_11F_REV not guaranteed accepted by
glReadPixels.

Bug: 556959073
TAG=agy
CONV=1a094951-4459-45eb-beb7-5195e47d5b48

Change-Id: Ida4e35bebb806a94f135f7f6bf9770b46b516d7d
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/340975
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Shrek Shao <shrekshao@google.com>
3 files changed
tree: 46dab67425823a5c6fa1dc5792e73885df10f7c4
  1. .github/
  2. .vscode/
  3. agents/
  4. build_overrides/
  5. docs/
  6. generator/
  7. include/
  8. infra/
  9. scripts/
  10. src/
  11. test/
  12. third_party/
  13. tools/
  14. webgpu-cts/
  15. .bazelignore
  16. .bazelrc
  17. .bazelversion
  18. .clang-format
  19. .clang-format-ignore
  20. .clang-tidy
  21. .git-blame-ignore-revs
  22. .gitattributes
  23. .gitignore
  24. .gitmodules
  25. .gn
  26. .style.yapf
  27. AUTHORS
  28. BUILD.bazel
  29. BUILD.gn
  30. CMakeLists.txt
  31. CMakeSettings.json
  32. CODE_OF_CONDUCT.md
  33. codereview.settings
  34. CONTRIBUTING.md
  35. CPPLINT.cfg
  36. DEPS
  37. DIR_METADATA
  38. go.mod
  39. go.sum
  40. go_presubmit_support.py
  41. LICENSE
  42. MODULE.bazel
  43. MODULE.bazel.lock
  44. OWNERS
  45. PRESUBMIT.py
  46. PRESUBMIT_test.py
  47. README.chromium
  48. README.md
  49. unsafe_buffers_paths.txt
  50. vpython.toml
  51. vpython.toml.uv.lock
  52. WATCHLISTS
  53. WORKSPACE.bazel
README.md

Build Status Matrix Space

Dawn, a WebGPU implementation

Dawn is an open-source and cross-platform implementation of the 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, Metal, Vulkan and OpenGL. See per API support for more details.
  • A client-server implementation of WebGPU for applications that are in a sandbox without access to native drivers
  • Tint is a compiler for the WebGPU Shader Language (WGSL) that can be used in standalone to convert shaders from and to WGSL.

Helpful links:

Documentation table of content

Developer documentation:

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

License

BSD 3-Clause License, please see LICENSE.

Disclaimer

This is not an officially supported Google product.