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 9	Direct3D 11	Desktop GL	GL ES	Vulkan	Metal
OpenGL ES 2.0	complete	complete	complete	complete	complete	complete
OpenGL ES 3.0		complete	complete	complete	complete	complete
OpenGL ES 3.1		incomplete	complete	complete	complete
OpenGL ES 3.2			in progress	in progress	complete

Additionally, OpenGL ES 1.1 is implemented in the front-end using OpenGL ES 3.0 features. This version of the specification is thus supported on all platforms specified above that support OpenGL ES 3.0 with known issues.

Platform support via backing renderers

	Direct3D 9	Direct3D 11	Desktop GL	GL ES	Vulkan	Metal
Windows	complete	complete	complete	complete	complete
Linux			complete		complete
Mac OS X			complete			complete [1]
iOS						complete [2]
Chrome OS				complete	planned
Android				complete	complete
Fuchsia					complete

[1] Metal is supported on macOS 10.14+

[2] Metal is supported on iOS 12+

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)
• OpenGL ES 3.2: ANGLE 2.1.2.21688.59f158c1695f (Sept, 2023)

ANGLE also provides an implementation of the EGL 1.5 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.

OpenCL Implementation

In addition to OpenGL ES, ANGLE also provides an optional OpenCL runtime built into the same output GLES lib.

This work/effort is currently work-in-progress/experimental.

This work provides the same benefits as the OpenGL implementation, having OpenCL APIs be translated to other HW-supported APIs available on that platform.

Level of OpenCL support via backing renderers

	Vulkan	OpenCL
OpenCL 1.0	in progress	in progress
OpenCL 1.1	in progress	in progress
OpenCL 1.2	in progress	in progress
OpenCL 3.0	in progress	in progress

Each supported backing renderer above ends up being an OpenCL Platform for the user to choose from.

The OpenCL backend is a “passthrough” implementation which does not perform any API translation at all, instead forwarding API calls to other OpenCL driver(s)/implementation(s).

OpenCL also has an online compiler component to it that is used to compile OpenCL C source code at runtime (similarly to GLES and GLSL). Depending on the chosen backend(s), compiler implementations may vary. Below is a list of renderers and what OpenCL C compiler implementation is used for each:

• Vulkan : clspv
• OpenCL : Compiler is part of the native driver

Sources

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

git clone https://chromium.googlesource.com/angle/angle

Building

View the Dev setup instructions.

Contributing

• Join our Google group to keep up to date.

• Join us on Slack in the #angle channel. You can follow the instructions on the Chromium developer page for the steps to join the Slack channel. For Googlers, please follow the instructions on this document to use your google or chromium email to join the Slack channel.

• File bugs in the issue tracker (preferably with an isolated test-case).

• Choose an ANGLE branch to track in your own project.

• Read ANGLE development documentation.

• Look at pending and merged changes.

• Become a code contributor.

• Use ANGLE’s coding standard.

• Learn how to build ANGLE for Chromium development.

• Get help on debugging ANGLE.

• Go through ANGLE’s orientation and sift through issues. If you decide to take on any task, write a comment so you can get in touch with us, and more importantly, set yourself as the “owner” of the bug. This avoids having multiple people accidentally working on the same issue.

• Read about WebGL on the Khronos WebGL Wiki.

• Learn about the internals of ANGLE:

  • Overview with a focus on the Vulkan backend (2022)
  • A short presentation on the Vulkan back-end (2018).
  • Historical presentation on the evolution of ANGLE and its use in Chromium
  • Historical presentation with a focus on D3D
  • The details of the initial implementation of ANGLE in the OpenGL Insights chapter on ANGLE (these details are severely out-of-date, and this reference is listed here for historical reference only)

• Read design docs on the Vulkan back-end

• Read about ANGLE’s testing infrastructure

• View information on ANGLE’s supported extensions

• If you use ANGLE in your own project, we’d love to hear about it!