Vulkan: Support vertex attribute aliasing for matrix types

This change builds on vertex attribute aliasing SPIR-V tranformation for
non-matrix types to add support for matrix attribute types.  This is
done by turning every matrix attribute declaration into multiple vector
attribute declarations, and reusing the same mechanism for resolving
aliasing between non-matrix types.

Take the following example:

    attribute mat4 a; // location 0
    attribute vec3 b; // location 1

    attribute mat3 c; // location 1
    attribute vec4 d; // location 2

The shader is modified as such:

    attribute vec4 a_0; // location 0
    attribute vec4 a_1; // location 1
    attribute vec4 a_2; // location 2
    attribute vec4 a_3; // location 3

    attribute vec3 c_0; // location 4
    attribute vec4 d;   // location 5
    attribute vec3 c_2; // location 6

    mat4 a;
    mat3 c;

and in the beginning of main(), the following code is inserted:

    a = mat4(a_0, a_1, a_2, a_3);
    c = mat3(c_0,, c_2);

The shader continues to use a and c as before.

Bug: angleproject:4249
Change-Id: Idfcb8c6037ca0c1f21de8203d7e2a1b66fed6e7e
Commit-Queue: Shahbaz Youssefi <>
Reviewed-by: Charlie Lao <>
Reviewed-by: Courtney Goeltzenleuchter <>
5 files changed
tree: 2f6b450d567b847818c373b1c30281a676ca1667
  1. .clang-format
  2. .gitattributes
  3. .gitignore
  4. .gn
  5. .style.yapf
  6. .vpython
  7. .vpython3
  8. .yapfignore
  12. DEPS
  14. OWNERS
  16. README.chromium
  19. additional_readme_paths.json
  20. android/
  21. build_overrides/
  22. codereview.settings
  23. doc/
  24. dotfile_settings.gni
  25. extensions/
  26. gni/
  27. include/
  28. infra/
  29. samples/
  30. scripts/
  31. src/
  32. third_party/
  33. tools/
  34. util/

ANGLE - Almost Native Graphics Layer Engine

The goal of ANGLE is to allow users of multiple operating systems to seamlessly run WebGL and other OpenGL ES content by translating OpenGL ES API calls to one of the hardware-supported APIs available for that platform. ANGLE currently provides translation from OpenGL ES 2.0, 3.0 and 3.1 to Vulkan, desktop OpenGL, OpenGL ES, Direct3D 9, and Direct3D 11. Future plans include ES 3.2, translation to Metal and MacOS, Chrome OS, and Fuchsia support.

Level of OpenGL ES support via backing renderers

Direct3D 9Direct3D 11Desktop GLGL ESVulkanMetal
OpenGL ES 2.0completecompletecompletecompletecompletecomplete
OpenGL ES 3.0completecompletecompletecompletein progress
OpenGL ES 3.1incompletecompletecompletecomplete
OpenGL ES 3.2in progressin progressin progress

Platform support via backing renderers

Direct3D 9Direct3D 11Desktop GLGL ESVulkanMetal
Mac OS Xcompletein progress
Chrome OScompleteplanned
GGP (Stadia)complete
Fuchsiain progress

ANGLE v1.0.772 was certified compliant by passing the OpenGL ES 2.0.3 conformance tests in October 2011.

ANGLE has received the following certifications with the Vulkan backend:

  • OpenGL ES 2.0: ANGLE 2.1.0.d46e2fb1e341 (Nov, 2019)
  • OpenGL ES 3.0: ANGLE 2.1.0.f18ff947360d (Feb, 2020)
  • OpenGL ES 3.1: ANGLE 2.1.0.f5dace0f1e57 (Jul, 2020)

ANGLE also provides an implementation of the EGL 1.4 specification.

ANGLE is used as the default WebGL backend for both Google Chrome and Mozilla Firefox on Windows platforms. Chrome uses ANGLE for all graphics rendering on Windows, including the accelerated Canvas2D implementation and the Native Client sandbox environment.

Portions of the ANGLE shader compiler are used as a shader validator and translator by WebGL implementations across multiple platforms. It is used on Mac OS X, Linux, and in mobile variants of the browsers. Having one shader validator helps to ensure that a consistent set of GLSL ES shaders are accepted across browsers and platforms. The shader translator can be used to translate shaders to other shading languages, and to optionally apply shader modifications to work around bugs or quirks in the native graphics drivers. The translator targets Desktop GLSL, Vulkan GLSL, Direct3D HLSL, and even ESSL for native GLES2 platforms.


ANGLE repository is hosted by Chromium project and can be browsed online or cloned with

git clone


View the Dev setup instructions.