Valve Opens Source Code for Lepton, a Compatibility Layer for Android Games on Linux
Valve has officially opened up the source code for Lepton, their compatibility layer designed to run Android games on Linux for the Steam Frame. The code is now available on their GitLab instance, released under the MIT license.
Similar to Proton, which allows Windows games to run on SteamOS/Linux, Valve’s focus with Lepton is specifically on getting Android games to work seamlessly. This move aims to make it easier for developers to bring their standalone games to the Steam Frame.
So, what exactly is Lepton? According to the GitLab page:
- Lepton is a tool for use with the Steam client, enabling exclusive Android games to run on the Linux operating system. Most users are advised to use Lepton provided by the Steam Client itself.
Lepton has unique design decisions that set it apart from other Android containerization projects:
- Lepton runs as a non-root user without requiring any rootful setup or helpers.
- Every process inside Lepton runs as the same non-root user, with no enforced isolation between apps.
- Lepton disables various Android services not required to run games, potentially affecting compatibility with some applications.
- It is not designed for general Android use, focusing on the minimum functionality needed to launch games.
- Lepton caches various pieces of state to accelerate Android userspace boot time.
- It is intended to help game developers bring their VR Android games to the Steam Frame.
Lepton also offers features to assist game developers in bringing their VR Android games to Steam:
- Mounting various libraries from the host OS, including graphics drivers, Steam/Steamworks libraries, and Vulkan layers.
- Support for integration with various debuggers and profilers.
- Hiding the flatscreen window by default, but can show it if necessary for development.
Additionally, Lepton incorporates patches and components from various projects in building the Android container root filesystem, released under GPL-3.0 license.
Valve’s commitment to open-source projects like Proton, Lepton, and FEX, along with their support for contractors working on Linux gaming infrastructure, continues to benefit the wider Linux gaming community.
It will be interesting to see the innovative uses of Lepton now that it is open to the public. Valve’s dedication to open-source initiatives and community support sets them apart from other gaming companies.
