mozangle

Mozilla’s fork of Google ANGLE, repackaged as a Rust crate.

• [ANGLE] is an implementation of OpenGL ES. Its official build system is gn, from Chromium’s [depot_tools].

• [mozilla/angle] on GitHub is a fork with some Gecko-specific patches.

• [gfx/angle] in mozilla-central is generated from that. [update-angle.py] runs gn desc to extract information from the official build system, copies relevant source files, and creates moz.build files for Gecko’s build system.

• This repository imports a copy of the gfx/angle directory. The generate_build_data.py script turns data from moz.build files into a Rust source file. (This script supports just enough of the moz.build format for this specific purpose.) Finally, a Cargo build script drives the C++ compilation with the [cc] crate based on that data.

Feature flags

By default, this crate only compiles the shader translator. This should be cross-platform, and can be used with:

toml [dependencies] mozangle = {git = "https://github.com/servo/mozangle"}

The egl Cargo feature enables the EGL and OpenGL ES implementations. This is only supported on Windows, since the Direct3D 11 rendering backend is configured.

toml [target.'cfg(windows)'.dependencies] mozangle = {git = "https://github.com/servo/mozangle", features = ["egl"]}

Updating ANGLE

To update:

• Remove gfx/angle entirely
• Copy a new version of it from mozilla-central
• Run python3 generate_build_data.py
• In the commit message, include the mozilla-central commit hash.