There were whispers about it just last week but now it’s totally official. Steam Play, which was originally intended as a single-purchase system for buying games that run on Windows, Mac, and Linux, is taking cross-platform compatibility to the next level. Yes, Valve is now testing running Windows games on Steam on Linux. And, much to the satisfaction of Linux and open source advocates, it’s doing it the right way by building on and supporting initiatives that will benefit not just Steam but the entire Linux ecosystem as well.
To be fair, Valve has long been an advocate of using industry-wide standards and technologies, even open source ones, over proprietary options, like using OpenGL or, now, Vulkan, over Microsoft’s Direct3D API. It put its foot where its mouth was when it bet on Linux for its SteamOS and Steam Machines, the latter of which unfortunately hasn’t borne much fruit yet. That could possibly change for the better with Valve’s new play for Steam Play.
Valve has fortunately decided to base its new Proton tool on the existing open source WINE (Wine Is Not an Emulator) project and has even collaborated with CodeWeavers, makers of the CrossOver Office Suite that lets Linux users run Microsoft Office, also based on WINE. While Proton does have some Steam-specific features, Valve has been pushing some of the improvements it has made on its side to the general WINE code in order to benefit all Linux users. And as expected, Valve is still pushing for developers to target the Vulkan graphics API (or at least OpenGL) instead of Direct3D in order to maximize platform support.
This Steam Play feature is available to all Linux users but they have to opt into the Steam Client Beta first. For now, the roster of whitelisted games ready for Steam Play is a bit short and varied, though Linux users can force Steam Play for all titles at their own risk. Those whitelisted games include:
• Beat Saber
• Bejeweled 2 Deluxe
• Doki Doki Literature Club!
• DOOM II: Hell on Earth
• DOOM VFR
• Fallout Shelter
• FINAL FANTASY VI
• Geometry Dash
• Google Earth VR
• Into The Breach
• Magic: The Gathering – Duels of the Planeswalkers 2012
• Magic: The Gathering – Duels of the Planeswalkers 2013
• Mount & Blade
• Mount & Blade: With Fire & Sword
• NieR: Automata
• PAYDAY: The Heist
• S.T.A.L.K.E.R.: Shadow of Chernobyl
• Star Wars: Battlefront 2
• Tekken 7
• The Last Remnant
• Tropico 4
• Ultimate Doom
• Warhammer® 40,000: Dawn of War® – Dark Crusade
• Warhammer® 40,000: Dawn of War® – Soulstorm
Valve admits that there will some performance impact, especially for games “where graphics API translation is required”, a.k.a. those using Direct3D. Windows games that use Vulkan from the get-go, however, should see not much difference, at least in theory. Some games that use DRM or anti-cheat systems, however, may not work at all. While this is definitely a huge boon for Linux gaming, it remains to be seen whether this will actually improve the market’s state or if it will simply make game developers less likely to support Vulkan or Linux directly since a compatibility tool exists anyway.