Workaround GL error when creating texture view from external GL textures

This patch adds a workaround on the GL error when we use glTextureView()
on a GL texture which is created outside DAWN and not configured by
glTexStorage*d(). glTextureView() is only allowed to be used on the
textures configured by glTexStorage*D(). When the external GL texture
is configured by glTexImage2D() (for example, textures from GLFW),
calling glTextureView() will cause an INVALID_OPERATION error.

To workaround this issue, we refer the solution on the Metal backend
that we avoid calling glTextureView() on the following senarios:
1. We may call glTextureView() only when the usage of the texture
   includes Sampled or Storage.
2. We won't call glTextureView() if the view uses the same format as the
   original texture, the whole mipmap levels and array slices.


Change-Id: Ibdfaa122ac061a2e2bb47f76e0030f1d0fc548a2
Reviewed-by: Kai Ninomiya <>
Commit-Queue: Jiawei Shao <>
2 files changed
tree: 9aed4f3fe1cb708efeff5f5618a4732dccf199b6
  1. .clang-format
  2. .gitignore
  3. .gn
  7. DEPS
  11. README.chromium
  13. build_overrides/
  14. codereview.settings
  15. dawn.json
  16. dawn_wire.json
  17. docs/
  18. examples/
  19. generator/
  20. infra/
  21. scripts/
  22. src/
  23. third_party/

Dawn, a WebGPU implementation

Dawn (formerly NXT) is an open-source and cross-platform implementation of the work-in-progress WebGPU standard. It exposes a C/C++ API that maps almost one-to-one to the WebGPU IDL and can be managed as part of a larger system such as a Web browser.

Dawn provides several WebGPU building blocks:

  • WebGPU C/C++ headers that applications and other building blocks use.
  • A “native” implementation of WebGPU using platforms' GPU APIs:
    • D3D12 on Windows 10
    • Metal on OSX (and eventually iOS)
    • Vulkan on Windows, Linux (eventually ChromeOS and Android too)
    • OpenGL as best effort where available
  • A client-server implementation of WebGPU for applications that are in a sandbox without access to native drivers

Directory structure

  • dawn.json: description of the API used to drive code generators.
  • examples: examples showing how Dawn is used.
  • generator: code generator for files produces from dawn.json
    • templates: Jinja2 templates for the generator
  • scripts: scripts to support things like continuous testing, build files, etc.
  • src:
    • common: helper code shared between core Dawn libraries and tests/samples
    • dawn_native: native implementation of WebGPU, one subfolder per backend
    • dawn_wire: client-server implementation of WebGPU
    • include: public headers for Dawn
    • tests: internal Dawn tests
      • end2end: WebGPU tests performing GPU operations
      • unittests: unittests and by extension tests not using the GPU
        • validation: WebGPU validation tests not using the GPU (frontend tests)
    • utils: helper code to use Dawn used by tests and samples
  • third_party: directory where dependencies live as well as their buildfiles.

Building Dawn

Dawn uses the Chromium build system and dependency management so you need to install depot_tools and add it to the PATH.

On Linux you need to have the pkg-config command:

# Install pkg-config on Ubuntu
sudo apt-get install pkg-config

Then get the source as follows:

# Clone the repo as "dawn"
git clone dawn && cd dawn

# Bootstrap the gclient configuration
cp scripts/standalone.gclient .gclient

# Fetch external dependencies and toolchains with gclient
gclient sync

Then generate build files using gn args out/Debug or gn args out/Release. A text editor will appear asking build options, the most common option is is_debug=true/false; otherwise gn args out/Release --list shows all the possible options.

Then use ninja -C out/Release to build dawn and for example ./out/Release/dawn_end2end_tests to run the tests.


Please read and follow Dawn doesn‘t have a formal coding style yet, except what’s defined by our clang format style. Overall try to use the same style and convention as code around your change.

If you find issues with Dawn, please feel free to report them on the bug tracker. For other discussions, please post to Dawn's mailing list.


Please see LICENSE.


This is not an officially supported Google product.