A clone of Zachtronics' Sawayama Solitaire (the single-pass Klondike variant from Last Call BBS), built in C++20 with SDL3. It runs natively on desktop and on the web as an installable PWA. Rendering is procedural (no image assets) and sound effects are synthesized at runtime, so SDL3 is the only third-party library; text uses the bundled single-header stb_truetype with a small embedded Inter subset (SIL OFL 1.1 — see assets/).

See docs/sawayama-solitaire.md for the full rules.

How to play

All tableau cards are face up. Build columns down in alternating colors.
Drag a card or an ordered run onto another column; any card or run may go into an empty column.
Click the stock to draw three at a time — there is only one pass, no reset. When the stock runs out, that slot becomes a single free cell.
Cards advance to the foundations automatically (a conservative auto-mover); double-click a card to force it up.
RE-DEAL starts a new (always winnable) game at any time. The speaker icon toggles sound. Lifetime wins are shown top-right and persisted.

Winnable deals

Every deal the game presents is guaranteed solvable. Roughly a quarter of random Sawayama layouts are unwinnable from the start, which isn't much fun, so deals are drawn from a pre-computed pool of seeds that an exhaustive solver proved winnable (src/pool_data.h, a compact bitmap). The deal RNG is xoshiro256** seeded via splitmix64 with an integer-only Fisher–Yates shuffle, so a given seed reproduces a byte-identical deal on every platform — which is exactly what lets a seed proven winnable by the native solver reproduce that same winnable deal in the wasm build.

The solver (tools/solver.cpp, native-only, built alongside the game) doubles as a Monte-Carlo winnability estimator. To regenerate the pool:

cmake --build build --target solver
# scan seeds [0, --bits) at a per-deal node budget; rewrite the bitmap header
./build/solver --genpool --bits 131072 --budget 2000000 --threads 16 --out src/pool_data.h
cmake --build build   # rebuild the game against the new pool

A higher --budget proves more of the harder deals winnable (less selection bias toward easy deals) at the cost of generation time; --bits sets the seed range scanned. Without --genpool, the solver runs the Monte-Carlo estimate instead (--deals N --budget B --threads T).

Build — native

Requires CMake ≥ 3.24 and a C++20 compiler. SDL3 is fetched automatically over HTTPS (pinned by SHA256) and linked statically.

cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build
./build/solitaire

Build — web (Emscripten)

Requires the Emscripten SDK (emcc on PATH).

emcmake cmake -B build-web -DCMAKE_BUILD_TYPE=Release
cmake --build build-web
# serve the output (a service worker requires http://, not file://)
python3 -m http.server -d build-web 8000
# open http://localhost:8000/index.html

The build emits index.html / index.js / index.wasm plus the PWA support files (manifest.webmanifest, sw.js, icons), so the page is installable and works offline after the first load. The service worker's cache name is stamped with a hash of the wasm at build time, so each deploy supersedes the old cache.

To deploy, install the complete site to any static HTTPS host (e.g. a GitHub Pages worktree):

cmake --install build-web --prefix /path/to/gh-pages-worktree

Pushing to master deploys automatically: the Deploy PWA GitHub Action (.github/workflows/deploy.yml) builds the PWA with Emscripten and force-pushes the installed site to the gh-pages branch. It can also be run on demand from the Actions tab (workflow_dispatch). Any existing gh-pages CNAME is preserved.

This copies the seven deployable files (including the stamped sw.js) into the prefix; all asset paths are relative, so subdirectory hosting works too.

Licenses

This project's own code is released into the public domain (see UNLICENSE). It bundles the following third-party components, whose licenses must accompany binary distributions:

SDL3 — zlib license (statically linked). https://www.libsdl.org/
Inter (embedded font subset, src/font_data.h) — SIL Open Font License 1.1. Copyright The Inter Project Authors. Full text in assets/Inter-LICENSE.txt.
stb_truetype (third_party/stb_truetype.h) — public domain.

The rules and presentation reimplement Sawayama Solitaire by Zachtronics; this is an independent fan project and is not affiliated with or endorsed by them.