Add support for rendering the wallpaper via Proton

[CrazyVito11]

Wallpaper Engine supports running wallpapers inside a separate window via CLI arguments.

This means we could get support for wallpapers that contain elements that are not supported yet by this project (3D and audio visualization for example)

Would it be theoretically possible to capture a specific window, and then project that inside the Plasma extension?
This could potentially be a separate option inside the plugin to run via Proton instead of rendering it natively.

---

I've made an example bash script on how to run a specific wallpaper inside a borderless window via Proton, which might be able to provide a starting point.

# The specific Steam Workshop ID of the scene you want to load
export SCENE_ID=1425503532

# The desired resolution
export WINDOW_WIDTH=1920
export WINDOW_HEIGHT=1080


export STEAM_APP_ID=431960
export STEAM_COMPAT_CLIENT_INSTALL_PATH=~/.steam/steam
export STEAM_COMPAT_DATA_PATH="${STEAM_COMPAT_CLIENT_INSTALL_PATH}/steamapps/compatdata/${STEAM_APP_ID}"
export WALLPAPER_ENGINE_INSTALL_PATH="${STEAM_COMPAT_CLIENT_INSTALL_PATH}/steamapps/common/wallpaper_engine"
export CURRENT_USER=$(whoami)

export SCENE_PATH="Z:\\home\\${CURRENT_USER}\\.local\\share\\Steam\\steamapps\\workshop\\content\\${STEAM_APP_ID}\\${SCENE_ID}\\scene.pkg"

~/.local/share/Steam/steamapps/common/Proton\ 8.0/proton run "${WALLPAPER_ENGINE_INSTALL_PATH}/wallpaper64.exe" \
  -control openWallpaper \
  -file "${SCENE_PATH}" \
  -playInWindow "KDE Wallpaper Engine" \
  -borderless \
  -width "${WINDOW_WIDTH}" \
  -height "${WINDOW_HEIGHT}"

[WaviestBalloon]

A heads-up for anybody who is running the bash script, Proton 9 fails to render and display wallpapers, Proton 8 works perfectly fine.

[yigekuyou]

plasma 6.0.3
proton experimental Wallpaper Engine make kwin_wayland freeze long time

[m3t4f1v3]

here's my implementation of it