spacewalk

The geometry instrument for operations conducted on a lattice, such as board games, tactics games, and tile maps: cells, directions, distance, sight, regions, and routes. Pieces, terrain, players, and the game clock remain under the command of your application.

🚀 Quick start

[dependencies]
spacewalk = "0.3"

use spacewalk::{Adjacency, FullGrid, Grid, Movement, Sq};

let grid = FullGrid::square(8, 8, Adjacency::Four);
let mud = [Sq::new(3, 3), Sq::new(3, 4)];

let movement = Movement::cell_cost(&grid, |cell| {
    Some(if mud.contains(&cell) { 30 } else { 10 })
});

let (from, to) = (grid.at(Sq::new(0, 0)), grid.at(Sq::new(7, 7)));
let route = grid
    .path(from, to, &movement)
    .expect("the route should be open");

assert_eq!(route.len(), 14);
assert_eq!(route.cells(&grid).count(), 15); // the start is included

👨‍🚀 Mission Objectives

Code written against the Grid trait runs on a board you built (FullGrid) or on a borrowed region of one (SubGrid) without a change of course.
Square, hex, disc, and tile-map hex rectangles ship as constructors. A custom Coord implementation opens anything else, including three-dimensional boards.
A step's cost belongs to the cell entered and the direction of arrival, so a river, a conveyor, or a one-way ledge needs no special case. A*, budget-bounded Dijkstra, and reverse reachability search the graph with deterministic tie-breaking. A Graph runs the same searches over nodes you name yourself, from a plain list of edges, with no grid at all.
Range, ring, component, and field-of-view queries return a SubGrid, so the thing you highlight is also the thing you path over.
Elevation lives in a CellMap beside your terrain. height::height_gate says what a hill hides and height::climb_gate what a ledge refuses, and both compose with the closures you already pass.
Pathfinding is integer arithmetic, so a replay reproduces. Floats exist only in the screen-layout layer, and no float ever reaches a cost, a metric, or a step.

👨‍🚀 Requirements and features

Rust 1.88 or newer, edition 2024.
#![no_std] with alloc; one runtime dependency (hashbrown).
serde feature: serialization for the plain-data types and CellMap. Grids rebuild from their cells; serialize coordinates, never indices.
Safety caps bound untrusted map files: MAX_CELLS is 2²⁴ cells and MAX_SIGHT is 64. Panicking constructors have try_ counterparts.

🧑‍🚀 More examples and documentation

API documentation: rustdoc is the manual, with the Grid vocabulary, cost models, metrics, index identity, and layouts.
tests/: public-API missions, from square tactics, checkers, hex capture, and three-dimensional chess to field of view, directed threats, save and load, and robustness at hostile numeric limits.
CHANGELOG
Issue tracker

👩‍⚖️ License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.