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:

[dependencies]
mozangle = "0.1"

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.

[target.'cfg(windows)'.dependencies]
mozangle = { version = "0.1", 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.