1 files changed, 156 insertions, 0 deletions
diff --git a/src/dungeon/mod.rs b/src/dungeon/mod.rs
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+++ b/src/dungeon/mod.rs
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+//! Turn-based dungeons: the map, field of view, derelict-ship generation,
+//! and the rules of a crawl. Drawing lives in `scenes::derelict`.
+
+pub mod crawl;
+pub mod fov;
+pub mod ship;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct Pos {
+    pub x: i32,
+    pub y: i32,
+}
+
+impl Pos {
+    pub const fn new(x: i32, y: i32) -> Pos {
+        Pos { x, y }
+    }
+
+    pub const fn offset(self, dx: i32, dy: i32) -> Pos {
+        Pos::new(self.x + dx, self.y + dy)
+    }
+
+    /// Steps from here to `other` when diagonal moves are allowed.
+    pub fn steps_to(self, other: Pos) -> i32 {
+        (self.x - other.x).abs().max((self.y - other.y).abs())
+    }
+
+    /// The eight cells around this one.
+    pub fn neighbours(self) -> impl Iterator<Item = Pos> {
+        const DIRS: [(i32, i32); 8] =
+            [(-1, -1), (0, -1), (1, -1), (-1, 0), (1, 0), (-1, 1), (0, 1), (1, 1)];
+        DIRS.into_iter().map(move |(dx, dy)| self.offset(dx, dy))
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Tile {
+    /// Outside the ship.
+    Void,
+    /// The outer skin of the ship.
+    Hull,
+    /// An inside wall.
+    Wall,
+    Floor,
+    /// Floor strewn with wreckage. Walkable; it just looks different.
+    Debris,
+    Door {
+        open: bool,
+    },
+    /// The way out: the airlock your own ship is docked to.
+    Airlock,
+}
+
+impl Tile {
+    /// Whether you can step onto it. Closed doors open when bumped instead,
+    /// and stepping into the airlock leaves the ship.
+    pub fn walkable(self) -> bool {
+        matches!(self, Tile::Floor | Tile::Debris | Tile::Door { open: true })
+    }
+
+    pub fn blocks_sight(self) -> bool {
+        matches!(
+            self,
+            Tile::Void | Tile::Hull | Tile::Wall | Tile::Door { open: false } | Tile::Airlock
+        )
+    }
+}
+
+/// A named area of the map, shown to the player while they stand in it.
+pub struct Room {
+    pub name: &'static str,
+}
+
+pub struct Map {
+    pub width: i32,
+    pub height: i32,
+    tiles: Vec<Tile>,
+    room_of: Vec<Option<u16>>,
+    pub rooms: Vec<Room>,
+}
+
+impl Map {
+    pub fn new(width: i32, height: i32, fill: Tile) -> Map {
+        let cells = (width * height) as usize;
+        Map {
+            width,
+            height,
+            tiles: vec![fill; cells],
+            room_of: vec![None; cells],
+            rooms: Vec::new(),
+        }
+    }
+
+    pub fn contains(&self, p: Pos) -> bool {
+        p.x >= 0 && p.y >= 0 && p.x < self.width && p.y < self.height
+    }
+
+    /// Index into a per-cell `Vec` laid out like the map. Panics off the map.
+    pub fn index(&self, p: Pos) -> usize {
+        assert!(self.contains(p), "{p:?} is off the map");
+        (p.y * self.width + p.x) as usize
+    }
+
+    /// The tile at `p`; everything off the map is `Void`.
+    pub fn tile(&self, p: Pos) -> Tile {
+        if self.contains(p) { self.tiles[self.index(p)] } else { Tile::Void }
+    }
+
+    pub fn set(&mut self, p: Pos, tile: Tile) {
+        let i = self.index(p);
+        self.tiles[i] = tile;
+    }
+
+    pub fn room_at(&self, p: Pos) -> Option<&Room> {
+        if !self.contains(p) {
+            return None;
+        }
+        self.room_of[self.index(p)].map(|r| &self.rooms[usize::from(r)])
+    }
+
+    pub fn add_room(&mut self, name: &'static str) -> u16 {
+        self.rooms.push(Room { name });
+        (self.rooms.len() - 1) as u16
+    }
+
+    pub fn set_room(&mut self, p: Pos, room: Option<u16>) {
+        let i = self.index(p);
+        self.room_of[i] = room;
+    }
+
+    pub fn positions(&self) -> impl Iterator<Item = Pos> + use<> {
+        let (w, h) = (self.width, self.height);
+        (0..h).flat_map(move |y| (0..w).map(move |x| Pos::new(x, y)))
+    }
+
+    /// Steps from `from` to every cell reachable through walkable tiles and
+    /// closed doors, moving diagonally too; `None` where unreachable.
+    pub fn distances_from(&self, from: Pos) -> Vec<Option<u32>> {
+        let mut dist = vec![None; self.tiles.len()];
+        let mut queue = std::collections::VecDeque::from([from]);
+        dist[self.index(from)] = Some(0);
+        while let Some(p) = queue.pop_front() {
+            let d = dist[self.index(p)].unwrap();
+            for n in p.neighbours() {
+                let tile = self.tile(n);
+                if (tile.walkable() || tile == (Tile::Door { open: false }))
+                    && dist[self.index(n)].is_none()
+                {
+                    dist[self.index(n)] = Some(d + 1);
+                    queue.push_back(n);
+                }
+            }
+        }
+        dist
+    }
+}