Catleap 🐱

Free, open-source macOS game launcher for running Windows games via Apple's Game Porting Toolkit. Click Play, your game runs.

Status: alpha. The first-run installer downloads a custom Wine build from this repo's GitHub Releases. No Homebrew required for end users.

Features

• Zero Homebrew — Catleap downloads its own Wine on first run; users never touch brew.
• Steam library detection — automatically scans your installed Steam games.
• GPTK D3DMetal integration — mount Apple's GPTK DMG once, Catleap copies the libraries into its data dir and wires them into every game launch (DirectX 11/12 → Metal).
• Compatibility database — curated env vars and DLL overrides for popular games.
• Manual game support — add any Windows .exe outside Steam.
• Isolated Wine prefixes — per-game, no cross-contamination.

Requirements

• macOS 14 (Sonoma) or newer
• Apple Silicon (M1 or later)
• ~500 MB free disk for the Wine binary (downloaded automatically)
• Free Apple Developer account (sign in at developer.apple.com) to download the GPTK DMG once

How it works

~/Library/Application Support/Catleap/
├── wine/                  ← downloaded from GitHub Releases on first run
│   ├── bin/wine64
│   └── lib/wine/...
├── gptk/lib/              ← copied from your mounted Apple GPTK DMG
│   ├── D3DMetal.framework/
│   └── external/*.dylib
└── prefixes/<game_id>/    ← created on demand at game launch

At launch, Catleap sets DYLD_FALLBACK_LIBRARY_PATH to the GPTK libs and runs wine64 under arch -x86_64. The Wine binary is compiled from Apple's official GPTK Wine sources (CodeWeavers 22.1.1 + Apple's patch) — no third-party Wine forks.

First run

1. Install Catleap (release coming; for now, build from source).
2. Click Continue through the welcome screen.
3. Wait ~1 minute for Catleap to download Wine (~150 MB).
4. Open developer.apple.com/games/game-porting-toolkit/, sign in with your Apple ID, download the GPTK DMG.
5. Mount the DMG. Catleap detects it automatically and imports the D3DMetal libraries (~20 MB).
6. Catleap scans your Steam library. Done.

If you skip step 4–5, games still launch but without Apple's DirectX-to-Metal translation — performance will be limited. You can import GPTK later from Settings.

Development

pnpm install
pnpm tauri dev      # run with hot reload
pnpm tauri build    # produce a distributable .app

The frontend is React + TypeScript + Tailwind v4. The backend is Rust + Tauri v2. Run cargo test --lib from src-tauri/ for the backend test suite.

Building the Wine artifact

The wine-catleap-<version>.tar.xz artifact that the first-run installer downloads is built by the Build Wine GitHub Actions workflow on a native Intel runner (macos-15-intel).

To cut a new Wine release:

gh workflow run build-wine.yml -f version=1.0.1

…or push a tag matching wine-catleap-v*:

git tag wine-catleap-v1.0.1
git push origin wine-catleap-v1.0.1

The workflow takes ~60 minutes. When it completes:

• A GitHub Release is published with the .tar.xz and .sha256 attached.
• A PR is opened updating WINE_EXPECTED_VERSION, WINE_RELEASE_URL, and WINE_EXPECTED_SHA256 in src-tauri/src/wine/installer.rs. Merge it to ship the new build.

Building locally (fallback) — see tools/build-wine/README.md. Requires Intel Homebrew at /usr/local/ and Rosetta 2.

Architecture

• src-tauri/src/wine/installer.rs — streaming download, SHA256 verify, tar.xz extract, ad-hoc codesign, atomic staging promote.
• src-tauri/src/wine/gptk_import.rs — /Volumes watcher, GPTK DMG version parsing, ditto-based copy with stage-and-promote.
• src-tauri/src/wine/runner.rs + prefix.rs — game launch with arch -x86_64, GPTK env vars when D3DMetal libs are present.
• src-tauri/src/wine/bundled.rs — Wine binary discovery (bundled → CrossOver → PATH).
• src-tauri/src/commands/onboarding.rs — IPC commands consumed by the FirstRun state machine.
• src/pages/FirstRun.tsx — five-step state machine: welcome → wine → gptk → scan → done.
• tools/build-wine/build.sh — manual offline build pipeline (also driven by CI).

Acknowledgements

• Apple — for the Game Porting Toolkit (D3DMetal, the patched Wine, the original toolchain).
• CodeWeavers — for the upstream Wine sources Apple builds on top of.
• gcenx/game-porting-toolkit — Catleap's bundled wine64 is a repackaging of gcenx's actively-maintained build of the same Apple/CodeWeavers sources, kept compiling on current macOS toolchains.

License

MIT