Cassia Aims To Pair Wine/DXVK/VKD3D-Proton/FEX For Windows Games On Android

Cassia is an in-development effort for running Microsoft Windows desktop games on Android. This work-in-progress effort is essentially akin to the Steam Play approach but targeted for Android users by leveraging Wine, DXVK, VKD3D-Proton, and then FEX for emulating x86_64 binaries on AArch64.

Danylo Piliaiev with Igalia presented at FOSDEM 2024 this morning in Brussels around the TURNIP Mesa driver providing open-source Vulkan API support for Qualcomm Adreno graphics hardware. This open-source Adreno Vulkan driver has been maturing nicely with Adreno 700 series support coming together, various new Vulkan API extensions being implemented, more correctness improvements, and other accomplishments.

TURNIP has been making nice progress and you can learn more about it via the FOSDEM presentation.

Brought up in that talk was the Cassia project that I previously hadn't heard of. Cassia is working on running desktop (Windows) games on Android by leveraging Wine, DXVK, VKD3D-Proton, and FEX-Core. Many of the same components powering Valve's Steam Play plus adding in FEX for handling the x86-64-on-AArch64 support.

Cassia sounds interesting but is still a work-in-progress and my excitement was a bit muted when reading more on it. This post outlines more details on Cassia for Android, with the hope of releasing it in 2024. The immediate disappointment to many is that Cassia is planning on being closed-source software. The developers say they will upstream changes to open-source projects they are leveraging, but that Cassia will be closed-source.... Except that if they decide to stop working on the project, they "commit" to then making it open-source.

Cassia will be focused solely on getting Windows games on Android and not Linux games. They also hope to be able to get Steam itself running under Cassia on Android.

Besides all the software challenges involved in getting Windows games running on Android AArch64 devices, there is also the matter of many Android devices not being powerful enough if you are thinking of running any AAA Windows games on your smartphone/tablet. In any event it will be interesting to see what comes of Cassia in 2024.