Arcen Games developers of AI War, The Last Federation, Bionic Dues have said they're no longer doing Native Linux support for their upcoming game Heart of the Machine and will instead rely on Proton.
What is the game? "Heart of the Machine is a near-future sci-fi colony city-builder in reverse — you are the first sentient Machine Intelligence in an established world rather than starting from nothing. No one knows you exist (yet), and this allows you to operate from the shadows by manipulating the human population for whatever purposes your programming has in mind. The twist is that whether humans live or die does not determine your victory."
This comes from a Steam announcement posted on August 11th, where they mentioned they plan to get it Steam Deck Verified as they're routinely testing it and Chris from Arcen Games spends "about 99% of my own gaming on that platform these days. It's a priority for me".
So why are they dropping Native Linux and going with the Proton compatibility layer? They said they found it performs better with Proton, looks better, has better frame timings and so Valve "strongly suggested we ditch the native version in that case". Going into more detail on the problems with their Native Linux build in Unity:
- Performance was 10% worse, and frametimings were less even, but it was certainly playable. This was just how Unity 3D works in Vulkan on Linux, so there was no way to solve it.
- Certain parts of this game have geometry that is close together, and on Linux these would flicker. This is because Unity 3D does not support a reversed z-buffer on OpenGL or Vulkan (or DirectX9). This problem is not present in DirectX11+, or Metal. And it’s not present when Proton or WINE convert DX11 commands to Vulkan.
Other than that, everything was the same on Linux as it is on Windows or OSX. We’ve had a native Linux build of this game for its entire life up until recently, just as all of Arcen’s titles have had a native Linux build for the last decade.
So this all feels very strange. But Unity 3D’s support for Linux, and in particular their implementation of Vulkan, is notably inferior to what is going on with their support for DirectX11 and Proton/WINE’s ability to bridge across.
They believe it's the best way right now for their games, because "If someone has an incompatibility, we can't change the engine" and that "Valve has been more on top of things than Unity".
It's due for release this year and you can follow it on Steam.