woggioni
dd3b918561
- fix the no-op best-score update that ignored all but the first reply - alternate sides correctly with negamax and add alpha-beta pruning - score terminal wins and losses above material evaluations - treat depth zero as one ply instead of underflowing - guard relative_score against an empty board - add hanging-piece, recapture, terminal, and depth regression tests
131 lines
3.7 KiB
Markdown
131 lines
3.7 KiB
Markdown
# rdraught
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A draughts (checkers) engine written in Rust, with a `no_std` core library and
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several front ends.
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## Workspace
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| Crate | Description |
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| --- | --- |
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| `rdraught` | `no_std` game engine, move generation, AI, and undo/redo history. |
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| `rdraught-ui-common` | Small geometry and shared-state helpers used by the graphical front ends. |
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| `rdraught-gtk` | GTK4 desktop front end (the most complete one). |
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| `rdraught-wasm` | Browser front end using the Canvas 2D API and `wasm-bindgen`. |
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| `rdraught-w4` | WASM-4 front end. Work in progress. |
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| `rdraught-sdl` | SDL3 front end. Work in progress. |
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| `rdraught-cli` | Scratch `rustyline` program; not a playable CLI yet. |
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## Rules
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The rules implemented by the engine are an 8x8 draughts variant:
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- Each player starts with twelve men.
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- Captures are mandatory.
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- A multi-capture sequence must be completed with the same piece.
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- Men move one square diagonally forward.
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- Men cannot capture backwards in this implementation.
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- Kings move one square diagonally in any direction and can capture in any
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direction.
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- A man is promoted to a king when it reaches the opponent's back row.
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- Draw rules (repetition, move limits) are not implemented yet.
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## AI
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The engine exposes a fixed-depth negamax search with alpha-beta pruning through
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`DraughtsGame::get_best_move(max_depth)`. A depth of zero is treated as one ply.
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Wins and losses dominate material scoring, and faster wins are preferred. The
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search has no time or node budget and no draw/repetition detection, so choose a
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modest depth for positions with many pieces.
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## Requirements
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- Rust 1.87 or newer. The workspace uses edition 2024.
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- `rustfmt` and `clippy` for the checks described below.
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- GTK4 development packages (including Graphene and librsvg) for
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`rdraught-gtk`.
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- The `wasm32-unknown-unknown` target and [Trunk](https://trunkrs.dev/) for
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`rdraught-wasm`.
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- The WASM-4 toolchain for `rdraught-w4`.
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- A C/C++ toolchain for `rdraught-sdl`, which builds SDL3 from source.
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On Debian/Ubuntu, the GTK front end needs packages such as:
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```sh
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sudo apt install libgtk-4-dev libgraphene-1.0-dev librsvg2-dev pkg-config
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```
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## Building and testing
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The default workspace members are `rdraught` and `rdraught-ui-common`, so the
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common host-side checks do not require GTK or a wasm target:
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```sh
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cargo test
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cargo test -p rdraught --features std
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cargo fmt --check
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cargo clippy -p rdraught --features std --all-targets
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```
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The draughts and AI unit tests are gated behind the `std` feature because they
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use `std::collections::HashMap`.
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`cargo test --workspace` requires all front-end prerequisites (GTK libraries,
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the wasm target, and the SDL build toolchain). Use the per-front-end commands
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below instead.
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### GTK
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```sh
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cargo run -p rdraught-gtk
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```
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### Browser WASM
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```sh
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rustup target add wasm32-unknown-unknown
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cd rdraught-wasm
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trunk serve --open
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```
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The `.cargo/config.toml` inside `rdraught-wasm` is only read when Cargo runs
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from that directory.
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### WASM-4
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```sh
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cd rdraught-w4
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cargo build --release --target wasm32-unknown-unknown
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```
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Run Cargo from `rdraught-w4` so its linker configuration is applied. The
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resulting module is in `target/wasm32-unknown-unknown/release/`.
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### SDL3
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```sh
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cargo run -p rdraught-sdl
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```
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The first build compiles SDL3 from source and can take a while.
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### CLI scratch program
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```sh
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cargo run -p rdraught-cli --bin rustyline-test
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```
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## Dependencies
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`rdraught-ui-common` uses `rmath`, which is published in the author's Gitea
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Cargo registry. The required registry configuration is committed in
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`.cargo/config.toml`, so no extra local setup is needed:
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```toml
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[registries.gitea]
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index = "sparse+https://gitea.woggioni.net/api/packages/woggioni/cargo/"
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```
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## License
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MIT. See [LICENSE](LICENSE).
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