--- name: nix-config-umu-game description: Use when installing a Windows game launcher (二次元 / gacha or any non-Steam game) on a NixOS desktop via umu-launcher, given an installer URL or an .exe, when such a launcher opens an invisible, transparent, black, or empty window under Wine, or when its download crawls behind the proxy. --- # Installing a Windows game launcher with umu The bundled `scripts/umu-install.nu` renders the files in `scripts/templates/`. It creates a prefix, runs the installer, and writes launchers. Use the Nix DW-Proton default unless research identifies a specific installed release; then select it with `PROTONPATH` and pin that path in the game's `conf`. **Every per-game detail lives under `~/Gaming/Games/`**, never in this repo. ## The sandbox Games run only inside the umu nixpak sandbox (`hardening/nixpaks/umu.nix`, policy in `hardening/nixpaks/modules/gaming-policy.nix`). It mounts `~/Gaming` over `$HOME`; no other host file is visible or writable. `umu-run`, `winetricks` and `bbe` exist only inside it (`mangohud` and `gamescope` are on the host too), and `umu-sandbox ` runs a command there. **Two views of one path:** `~/Gaming/` on the host is `~/` in the sandbox, so a game lives at `~/Gaming/Games/` on the host and at `~/Games/` inside. The host has no `~/Games`: a path written that way is a sandbox path. Typed after `umu-sandbox` in a host shell, `~/Games//run` expands to exactly that sandbox path. Host environment variables do not reach the sandbox; put them in `conf`. Everything under `~/Gaming` is writable by the games, so **the host never executes a file from it**: - launch with `umu-sandbox ~/Games//run` and use `umu-sandbox ~/Games//exec ...`; the generated desktop entry does the former. Running `run` or `exec` directly refuses to start. - the installer and `prelaunch` also run through `umu-sandbox`; - `umu-install.nu` refuses to write through a symlink in the game directory and writes its files there through `umu-sandbox`, so a symlink swapped in later still cannot reach outside `~/Gaming`; uninstalling uses the repo's `umu-uninstall.nu`, not a script in `~/Gaming`. ## Bundled files - `scripts/umu-install.nu`: installer and template renderer - `scripts/umu-uninstall.nu`: removes a game's desktop entry and, after confirmation, its directory - `scripts/common.nu`: name, symlink and sandbox-path helpers shared by both - `scripts/templates/*.tpl`: non-executable templates; placeholders use `@NAME@` - `scripts/tests/test_install.py`: offline regression tests ## Layout Host paths; inside the sandbox drop the `Gaming/`. - `~/Gaming`: the sandbox's `$HOME`, shared with the other game launchers (umu runtime, Steam, Heroic, saves written to `$HOME`) - `~/Gaming/Games/global.conf`: optional, sourced by every game before its own `conf` - `~/Gaming/Games//prefix`: the Wine prefix (`WINEPREFIX`) - `~/Gaming/Games//conf`: optional per-game overrides (`ENABLE_MANGOHUD=0`, ...) - `~/Gaming/Games//prelaunch`: optional executable, run before every launch - `~/Gaming/Games//run`: generated launcher - `~/Gaming/Games//exec`: generated helper: `umu-sandbox ~/Games//exec ` - `~/Gaming/Games//.desktop`: generated desktop entry Run, from the repo root: `nu .agents/skills/nix-config-umu-game/scripts/umu-install.nu [gameid] [setup-args...]` `` is relative to the prefix and `GAMEID` defaults to `umu-default`. A `` outside `~/Gaming` is copied into the game directory first; `-` skips the installer and only rewrites `run`, `exec` and the desktop entry. At install, `PROTONPATH` resolves from `$PROTONPATH`, `$UMU_PROTONPATH` (the Nix-provided DW-Proton), then Steam's per-user `compatibilitytools.d` in the sandbox home; it must be a store path or under `~/Gaming`. `run`, `exec` and the desktop entry hold sandbox paths. At launch, the generated `run` script checks the current `$PROTONPATH` and `$UMU_PROTONPATH` before its saved default. A game's `conf` is sourced after those defaults, so set `PROTONPATH` there to pin a particular installed version across launches. ## Procedure 1. **Research first.** Mandatory before inventing any fix: a documented fix beats a custom patch every time. Check the game's Lutris installer YAML as data only (`https://lutris.net/api/installers/` encodes `winetricks` verbs, `write_file` content, and `prelaunch_command`; do not install or run Lutris), then ProtonDB (`protondb.com/app/`), Steam Community / r/linux_gaming threads, and GitHub issues for the launcher and Proton. Record whether reports require a Proton family and exact release. If no exact release is required, use the Nix-provided DW-Proton default. If one is required, inspect `$UMU_PROTONPATH`, the Nix GE-Proton (`nix build --no-link --print-out-paths .#nixosConfigurations..pkgs.proton-ge-bin.steamcompattool`) and installed Steam tools under `~/Gaming/.local/share/Steam/compatibilitytools.d/` (the sandbox's `~/.local/share/Steam/compatibilitytools.d/`); select the matching installed path with `PROTONPATH`. Prefix the installer command with `PROTONPATH=""` and set its sandbox path (a store path as is; under `~/Gaming`, drop the `Gaming/`) in the game's `conf` to pin it across launches; otherwise the runtime Nix `UMU_PROTONPATH` may take precedence. If the required release is absent from Nix and Steam, stop and ask the user before downloading it from elsewhere. Do not substitute a different release or use ProtonPlus/Lutris to fetch one: a host-side downloader writes outside `~/Gaming`, where the sandbox cannot see it, and a store path cannot be modified by a game. 2. **Slug.** Pick a lowercase `` (e.g. `wuthering-waves`). 3. **GAMEID.** The umu database maps a title to a `GAMEID` whose protonfixes add CJK fonts, drop the `SteamOS`/`SteamDeck` vars, and keep Wine's `Documents` inside the prefix. **Without it some games save into the host home or the wrong prefix.** Fetch `https://raw.githubusercontent.com/Open-Wine-Components/umu-database/main/umu-database.csv`, match the title, and use its `umu-`; if nothing matches, leave the default. 4. **Download.** `curl -fL -o ~/Gaming/Games//setup.exe`. The CN store pages are JS/token driven, so the user normally supplies the URL or the file itself. 5. **Install.** Run the bundled script. The first run also downloads umu's Steam runtime and the protonfix fonts, so it is slow. The installer is usually a GUI the user clicks through, but **extra args after `[gameid]` go to `setup.exe`**, so try a silent flag first (`/S`, `/quiet`, `--silent`); if it ignores them, fall back to clicking. On some CN installers the last page auto-starts the launcher. The script writes `run`/`exec` even if the installer exits non-zero, so a killed installer is not fatal. 6. **Find the launcher.** If `` is only known after install, locate it under `~/Gaming/Games//prefix/drive_c` and set `LAUNCHER` in `~/Gaming/Games//conf`. Re-running the installer script invokes `setup.exe` again; only do so if that installer is known to handle reruns. 7. **Per-game fix.** Port step 1 findings into `~/Gaming/Games//prelaunch` (bash, `chmod +x`): `winetricks` verbs via `~/Games//exec winetricks `, file patches or registry tweaks via `~/Games//exec`. `prelaunch` runs in the sandbox, so it uses sandbox paths and calls `exec` directly; from a host shell, prefix it with `umu-sandbox`. Never commit the fix to this repo. 8. **Re-run every launch, not once.** A launcher that self-updates overwrites files it patches, so those patches belong in `prelaunch`. 9. **Verify.** `umu-sandbox ~/Games//run` must open a visible launcher window. MangoHud is enabled by default with FPS and frame time at the top-left; set `ENABLE_MANGOHUD=0` in `conf` to disable it, or override `MANGOHUD_CONFIG`. Re-running `prelaunch` must be idempotent. The launcher may then download the game body itself (tens of GB) -- that is the launcher's job, not this skill's, so the install is **done** once the window is usable. A crawl usually means the proxy: the launcher probes the CDN itself and mihomo routes that probe through a distant node, so the download starts from a far mirror; routing is in the [mihomo README](../../../modules/nixos/desktop/networking/mihomo/README.md). `ENABLE_LOG=1` captures `last-run.log` when something misbehaves. ## Invisible / transparent launcher window A WebView2/.NET (WPF) launcher that shows an empty or fully transparent window is rendering with `AllowsTransparency`. Fix the DLL, not Wine: 1. `find ~/Gaming/Games//prefix/drive_c -iname 'launcher_main.dll'` (usually under a `X.Y.Z.W` version dir). 2. Rename that WPF property in place, keeping the byte length so PE offsets stay valid: `bbe -e 's/\x12AllowsTransparency/\x09IsEnabled\x1bA\x00\x03AAAAA/' `. `bbe` exists only in the sandbox: prefix it with `umu-sandbox` from a host shell. 3. Put it in `~/Gaming/Games//prelaunch` so it is re-applied on every launch, because a launcher self-update restores the original DLL. Restart the launcher after patching. ## Half-width tile instead of fullscreen Niri tiles a new window into a column of `default-column-width { proportion 0.500000; }` (50%), and a launcher that only opens a large borderless window cannot take over the screen by itself: with a 4K panel at `scale 1.5` Niri's logical space is 2560x1440, so a window asking for the physical 3840x2160 becomes an ordinary half-width tile. Nothing is broken -- the umu app-id is just not covered by a rule. Every umu/Proton game reports `steam_app_`. In this repo `home/linux/gui/niri/conf/windowrules.kdl` matches `app-id="^steam_app_[0-9]+$"` and sets `open-fullscreen true`, so games open fullscreen without a per-game rule. `niri validate` checks the live config, `Mod+Shift+F` (`fullscreen-window`) toggles an already-open window, and setting the in-game resolution to the compositor's logical size (2560x1440 here) avoids the mismatch too. A launcher shares that app id with its game, so the rule also catches the launcher's own windows: a helper that is still untitled while it maps, and the announcement popup (公告 / Announcement), which on this launcher renders as a pure white rectangle. Fullscreening either one buries the UI that opened it, so both are excluded. A window rule applies when a window opens, so an already-open offender needs `Mod+Shift+F` on it or a relaunch; drop `open-fullscreen true` altogether if a launcher keeps surprising you -- the game then costs one `Mod+Shift+F` per session instead. ## Mojibake that is not a missing font Latin-looking garbage such as `我已阅读` where the launcher should say 我已阅读并同意, while other Chinese on the same window renders fine, is UTF-8 decoded as Windows-1252. Confirm the pattern: ```bash python3 -c "print('我已阅读并同意'.encode('utf-8').decode('cp1252','replace'))" ``` If that prints exactly what the launcher shows, the bug is identified and you can stop here. The string itself is fine and so are the fonts: the same launcher renders 请输入手机号 and 登录 correctly, and the garbled label exists as correct UTF-16 in `KRSDKEx.dll`. The bytes are simply decoded with a single-byte Western codepage. **This is not the prefix locale.** Setting `LANG=zh_CN.UTF-8` in `~/Gaming/Games//conf` does change the prefix (verified in this repo: `"ACP"` went `1252` -> `936` and `"LocaleName"` `en-US` -> `zh-CN`), and the garbling stayed **byte-for-byte identical**. The launcher decodes those bytes as Latin-1 no matter what Windows codepage it is told to use, so this is an upstream bug in its own text pipeline: report it, or accept it -- the launcher still works. `LANG` is nevertheless the lever for the prefix locale, not `LC_ALL`: Proton clears `LC_ALL` unless `HOST_LC_ALL` is set. So: check the bytes first, do not install more CJK fonts, and do not promise a locale fix. ## Silent install `umu-install.nu /S` passes `/S` to the installer. Not all installers honour it; try `/quiet` or `--silent` too, then fall back to the GUI. ## Desktop entry and persistence The script also writes `~/.local/share/applications/.desktop` (and a copy at `~/Gaming/Games//.desktop`), so the game shows up in the desktop launcher. The host copy is written by the installer on the host; the sandbox cannot see or change it. Under an impermanence setup both `~/Gaming` and `~/.local/share/applications` must be in the host's `preservation.preserveAt` list, in `hosts//preservation.nix`. ## Uninstall From the repo root: `nu .agents/skills/nix-config-umu-game/scripts/umu-uninstall.nu ` It removes the desktop entry, but only one whose `Exec` is the generated `umu-sandbox ~/Games//run`, and then asks before deleting `~/Gaming/Games/` (prefix + game files). To keep the game and only drop the menu entry, delete the `.desktop` file by hand. ## Games installed before the sandbox After deploying the sandbox and with every game closed, move `~/Games` to `~/Gaming/Games` and the old `~/.local/share/umu` to `~/Gaming/.local/share/umu` (umu can also download its runtime again). On a normal host that is a plain `mv`. On an impermanence host each preserved directory is its own bind mount, and after the deploy the old ones are no longer mounted, so move them under the persistent root instead, where both are renames: ```bash mkdir -p /persistent/home//Gaming/.local/share mv /persistent/home//Games /persistent/home//Gaming/Games mv /persistent/home//.local/share/umu /persistent/home//Gaming/.local/share/umu ``` `/persistent` is the host's `preservation.preserveAt` root. If a target already exists, `mv` would nest the source inside it: move the game directories one by one instead, and drop the old umu runtime. Paths inside the game directories stay valid, because the sandbox sees them at the old `~/Games/`. The old desktop entries execute `run` on the host, and an old `uninstall` script is host-executed too, so rewrite the launchers without re-running the installer, passing the `LAUNCHER` and `GAMEID` from the old `run`: `nu .agents/skills/nix-config-umu-game/scripts/umu-install.nu - ` This also deletes the old `uninstall`. ## Optimize the launch `~/Gaming/Games//conf` (or `~/Gaming/Games/global.conf`) is a shell file the generated `run` sources. Defaults are `ENABLE_MANGOHUD=1`, `MANGOHUD_CONFIG="fps=1,frametime=1,position=top-left"`, `ENABLE_GAMEMODE=0`, `ENABLE_GAMESCOPE=0`, `GAMESCOPE_ARGS="-f"`, and `ENABLE_LOG=0`. Set `ENABLE_MANGOHUD=0` to hide the overlay, `ENABLE_GAMESCOPE=1` + `GAMESCOPE_ARGS="-f -w 3840 -h 2160"` for the handheld / multi-monitor case, and `ENABLE_LOG=1` to capture the run. Gamescope runs inside the sandbox without `CAP_SYS_NICE`, so it cannot raise its own priority. `ENABLE_GAMEMODE=1` has no effect: `gamemoderun` is not in the sandbox, whose PID namespace and D-Bus filter keep `gamemoded` from managing the game. A host wrapper such as `nvidia-offload` does not work either, because the sandbox clears the environment; export its variables (`__NV_PRIME_RENDER_OFFLOAD=1`, ...) in `conf` instead. Shader caches are kept in `~/Gaming/Games//shader-cache`. ## Escape hatches - `umu-sandbox ~/Games//exec [args...]` runs anything in the prefix with the right env: an absolute path to a game exe or repair tool, or a bare Wine tool (`winecfg`, `explorer`, `regedit`, `uninstaller`), which it runs as `umu-run `. Both forms are handed to `umu-run`, so they execute inside umu's Steam runtime container -- that is what makes them work on a non-FHS distro like NixOS, where Proton's wine cannot start on its own. - `umu-sandbox ~/Games//run ` passes extra args to the launcher. - Kill a stuck prefix with `pkill -f '/Games//prefix'`, or `rm -f ~/Gaming/Games//prefix/pfx.lock`. ## Common mistakes - Launching again while the first launch after a Proton update or a moved umu runtime shows no window: it is preparing steamrt4 and upgrading the prefix, which can take a minute, and a second launch blocks on the same locks. Wait, or `pkill -f '/Games//prefix'` and launch once. - Committing a game name, URL, or patch to this repo instead of `~/Gaming/Games//`. - Patching once instead of in `prelaunch` -- the next launcher self-update undoes it. - Dropping the `GAMEID` -- the in-game CJK fonts and the save location go wrong. - Installing more CJK fonts when the text is mojibake -- decode the bytes first (see above). - Expecting umu to fetch DW-Proton: it only auto-manages GE-Proton / UMU-Proton; use Nix or Steam installed paths. Ask the user before obtaining a required release from elsewhere. - Running a Wine tool without umu. `umu-run winecfg` does not work -- umu only special-cases `winetricks` -- and `$PROTONPATH/files/bin/wine winecfg` fails on any non-FHS distro (on NixOS the 32-bit loader it needs lives only inside the Steam runtime container). Use `umu-sandbox ~/Games//exec winecfg`; `exec` goes through `umu-run`, which provides that container. - Running `run`, `exec` or `prelaunch` from a host shell, or adding a host-side helper that executes a file under `~/Gaming`: games can rewrite those files. Go through `umu-sandbox`. - Pointing `PROTONPATH`, a launcher or an installer at a host path outside `~/Gaming`: the sandbox cannot see it. Inside `conf` and `prelaunch`, write sandbox paths (`~/Games/`). - Waiting for the game download before calling the install done: the launcher's own download is out of scope here. - On NixOS a game needing 32-bit or Vulkan needs `hardware.graphics.enable32Bit`, which `modules/nixos/desktop/gaming.nix` sets. Steam is a sandboxed package like umu: `hardening/nixpaks/steam.nix`. ## Regression tests From the repo root: ```bash python3 .agents/skills/nix-config-umu-game/scripts/tests/test_install.py ``` Requires `python3`, `nu`, `bash`, and `shellcheck`; the symlink-swap test also needs `unshare` and unprivileged user namespaces, and is skipped without them. Uses temporary homes and stub `umu-run` and `umu-sandbox`; no game downloads, Wine windows, or changes to existing games. It checks template permissions, rendered shell syntax and lint, installer arguments and failures, configuration precedence, prelaunch, logging, launch wrappers, literal paths, runtime Proton overrides, tool routing, uninstall confirmation and foreign desktop entries, the sandbox guard, host-to-sandbox path translation, refusal to write through planted symlinks, and that a symlink swapped in after that check cannot redirect a write outside `~/Gaming`.