Files
rdraught/README.md
T
woggioni f17d328ed5 fix frontend board mapping, game-over handling, and WASM-4
- fix Xform yx and add a shared view-aware board_position helper
- add GTK automatic game-over, restart, status, and multi-capture selection
- pin librsvg to the 2.60 series to match GTK4/glib 0.20
- add WASM orientation, undo/redo/new/flip controls, and winner overlay
- replace WASM crown images with canvas paths and remove dead files/deps
- make WASM-4 playable with mouse input, crowns, winner handling, and correct mapping
- move the WASM-4 release profile to the workspace root
- clean up frontend dead code and update the README
2026-10-19 20:38:32 +00:00

4.5 KiB

rdraught

A draughts (checkers) engine written in Rust, with a no_std core library and several front ends.

Workspace

Crate Description
rdraught no_std game engine, move generation, AI, and undo/redo history.
rdraught-ui-common Small geometry and shared-state helpers used by the graphical front ends.
rdraught-gtk Playable GTK4 desktop front end.
rdraught-wasm Playable browser front end using the Canvas 2D API and wasm-bindgen.
rdraught-w4 Playable WASM-4 front end.
rdraught-sdl SDL3 prototype; not wired to the game yet.
rdraught-cli Scratch rustyline program; not a playable CLI yet.

The GTK, WASM, and WASM-4 front ends are currently hot-seat games: both sides are played by people. The core AI is available but is not wired into a frontend yet.

Rules

The rules implemented by the engine are an 8x8 draughts variant:

  • Each player starts with twelve men.
  • Captures are mandatory.
  • A multi-capture sequence must be completed with the same piece.
  • Men move one square diagonally forward.
  • Men cannot capture backwards in this implementation.
  • Kings move one square diagonally in any direction and can capture in any direction.
  • A man is promoted to a king when it reaches the opponent's back row.
  • Draw rules (repetition, move limits) are not implemented yet.

AI

The engine exposes a fixed-depth negamax search with alpha-beta pruning through DraughtsGame::get_best_move(max_depth). A depth of zero is treated as one ply. Wins and losses dominate material scoring, and faster wins are preferred. The search has no time or node budget and no draw/repetition detection, so choose a modest depth for positions with many pieces. The current frontends do not use the AI; they are hot-seat games.

Requirements

  • Rust 1.87 or newer. The workspace uses edition 2024.
  • rustfmt and clippy for the checks described below.
  • GTK4 development packages (including Graphene and librsvg) for rdraught-gtk.
  • The wasm32-unknown-unknown target and Trunk for rdraught-wasm.
  • The WASM-4 toolchain for rdraught-w4.
  • A C/C++ toolchain for rdraught-sdl, which builds SDL3 from source.

On Debian/Ubuntu, the GTK front end needs packages such as:

sudo apt install libgtk-4-dev libgraphene-1.0-dev librsvg2-dev pkg-config

Building and testing

The default workspace members are rdraught and rdraught-ui-common, so the common host-side checks do not require GTK or a wasm target:

cargo test
cargo test -p rdraught --features std
cargo fmt --check
cargo clippy -p rdraught --features std --all-targets

The draughts and AI unit tests are gated behind the std feature because they use std::collections::HashMap.

cargo test --workspace requires all front-end prerequisites (GTK libraries, the wasm target, and the SDL build toolchain). Use the per-front-end commands below instead.

GTK

cargo run -p rdraught-gtk

Use the board orientation selector at startup, click a piece to select it, and click a highlighted destination to move. The header bar has undo, redo, and New Game buttons. The game-over dialog appears automatically; use New Game to start another game.

Browser WASM

rustup target add wasm32-unknown-unknown
cd rdraught-wasm
trunk serve --open

Click a piece and then a highlighted destination. Keyboard controls:

  • Ctrl+Z — undo
  • Ctrl+Y or Ctrl+Shift+Z — redo
  • N — new game
  • F — flip the board orientation

The .cargo/config.toml inside rdraught-wasm is only read when Cargo runs from that directory.

WASM-4

cd rdraught-w4
cargo build --release --target wasm32-unknown-unknown

Run Cargo from rdraught-w4 so its linker configuration is applied. The module is written to ../target/wasm32-unknown-unknown/release/rdraught_w4.wasm.

Use the mouse to select a piece and click a highlighted destination to move. After a win, click to start a new game. The board is shown in a fixed orientation for hot-seat play.

SDL3

cargo run -p rdraught-sdl

The first build compiles SDL3 from source and can take a while.

CLI scratch program

cargo run -p rdraught-cli --bin rustyline-test

Dependencies

rdraught-ui-common uses rmath, which is published in the author's Gitea Cargo registry. The required registry configuration is committed in .cargo/config.toml, so no extra local setup is needed:

[registries.gitea]
index = "sparse+https://gitea.woggioni.net/api/packages/woggioni/cargo/"

License

MIT. See LICENSE.