Pyroveil is a Vulkan layer that can automatically replace shaders or roundtrip them via SPIRV-Cross -> glslang. This can create SPIR-V that is more compatible with NVIDIA drivers in particular.

Make sure to install git, cmake, ninja and gcc toolchains first (often called base-devel or similar).

git clone https://github.com/HansKristian-Work/pyroveil.git
cd pyroveil
git submodule update --init
cmake . -Bbuild -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=$HOME/.local
ninja -C build install

Alternative path if using Steam Flatpak. (I assume this is correct).

cmake . -Bbuild -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=$HOME/.var/app/com.valvesoftware.Steam/.local

The layer needs a config file to operate. See the folders under hacks/ for some ready to go config files. Use PYROVEIL_CONFIG=/path/to/pyroveil.json to pick the config you want. In Steam, run the game with PYROVEIL=1 %command%.

To know that it's active, run grep "pyroveil:" ~/steam-$appid.txt on the PROTON_LOG output. You should see, e.g.:

pyroveil: Found config in /tmp/pyroveil.json!
pyroveil: Adding match for spirvExecutionModel: 5365 (MeshEXT).
pyroveil: Adding GLSL roundtrip via SPIRV-Cross for match.
...
pyroveil: Found match for execution model in 55736cd1c3064f67.
...

Some config files use a roundtripCache to provide patched SPIR-V. In this case, cache/ folder next to pyroveil.json must also be copied. It is likely easier to simply use the path that you checked out for the pyroveil.json. E.g.

PYROVEIL=1 PYROVEIL_CONFIG=/path/to/pyroveil/checkout/hacks/monster-hunter-wilds-nv/pyroveil.json %command%

Some manual workarounds will be required to make this work with a Bottles setup.

Assuming you have gone through the checkout and build section, you will now have two files in the CMAKE_INSTALL_PREFIX directory:

• $CMAKE_INSTALL_PREFIX/lib/libVkLayer_pyroveil_64.so
• $CMAKE_INSTALL_PREFIX/share/vulkan/implicit_layer.d/VkLayer_pyroveil_64.json

By default Bottles will search several locations for Vulkan layer manifests, one of them is:

• $HOME/.var/app/com.usebottles.bottles/config/vulkan/implicit_layer.d

Copy over VkLayer_pyroveil_64.json into the location above. Open it and edit ONLY the layer.library_path field in the json like so (or any other path you like, as long as Bottles can access it):

    "layer" : {
        "library_path": "/home/YOUR_USER/.var/app/com.usebottles.bottles/config/vulkan/lib/libVkLayer_pyroveil_64.so"
    }

For the final step it's suggested to copy the relevant hack to the drive_c folder of your game.

Finally, in the Bottles app, set the Launch options by clicking on the three dots next to your Program/Game, and clicking "Change Launch Options". Next add one of the hack locations:

PYROVEIL=1 PYROVEIL_CONFIG=/home/YOUR_USER/.var/app/com.usebottles.bottles/data/bottles/bottles/YOUR_BOTTLE/drive_c/pyroveil.json %command%

NOTE: If you are running an older version of a game, you might want to check the git history for that particular game's hack, and try an older version of the hack file.