feat(generator): add maze backtracking generator

Cargo.lock

@@ -2,6 +2,29 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "byteorder"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fd0f2584146f6f2ef48085050886acf353beff7305ebd1ae69500e27c67f64b"
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "getrandom"
+version = "0.2.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4567c8db10ae91089c99af84c68c38da3ec2f087c3f82960bcdbf3656b6f4d7"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
 [[package]]
 name = "glam"
 version = "0.27.0"
@@ -16,6 +39,7 @@ name = "hexlab"
 version = "0.1.0"
 dependencies = [
  "hexx",
+ "rand",
  "serde",
  "serde_json",
 ]
@@ -36,12 +60,27 @@ version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49f1f14873335454500d59611f1cf4a4b0f786f9ac11f4312a78e4cf2566695b"
 
+[[package]]
+name = "libc"
+version = "0.2.161"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e9489c2807c139ffd9c1794f4af0ebe86a828db53ecdc7fea2111d0fed085d1"
+
 [[package]]
 name = "memchr"
 version = "2.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77957b295656769bb8ad2b6a6b09d897d94f05c41b069aede1fcdaa675eaea04"
+dependencies = [
+ "zerocopy",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.89"
@@ -60,6 +99,36 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rand"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+dependencies = [
+ "getrandom",
+]
+
 [[package]]
 name = "ryu"
 version = "1.0.18"
@@ -114,3 +183,30 @@ name = "unicode-ident"
 version = "1.0.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e91b56cd4cadaeb79bbf1a5645f6b4f8dc5bde8834ad5894a8db35fda9efa1fe"
+
+[[package]]
+name = "wasi"
+version = "0.11.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
+
+[[package]]
+name = "zerocopy"
+version = "0.7.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b9b4fd18abc82b8136838da5d50bae7bdea537c574d8dc1a34ed098d6c166f0"
+dependencies = [
+ "byteorder",
+ "zerocopy-derive",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.7.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa4f8080344d4671fb4e831a13ad1e68092748387dfc4f55e356242fae12ce3e"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]

Cargo.toml

@@ -7,6 +7,7 @@ license = "MIT OR Apache-2.0"
 
 [dependencies]
 hexx = { version = "0.18" }
+rand = "0.8"
 serde = { version = "1.0", features = ["derive"], optional = true }
 
 [features]

src/generator.rs

@@ -0,0 +1,89 @@
+use std::collections::HashSet;
+
+use hexx::{EdgeDirection, Hex};
+use rand::{rngs::ThreadRng, seq::SliceRandom, thread_rng};
+
+use crate::HexMaze;
+
+#[derive(Debug, Clone, Copy)]
+pub enum GeneratorType {
+    BackTracking,
+}
+
+impl HexMaze {
+    pub fn generate(&mut self, generator_type: GeneratorType) {
+        match generator_type {
+            GeneratorType::BackTracking => self.generate_backtracking(),
+        }
+    }
+
+    pub fn generate_backtracking(&mut self) {
+        if self.is_empty() {
+            return;
+        }
+        let start = *self.tiles().keys().next().unwrap();
+
+        let mut visited = HashSet::new();
+        let mut rng = thread_rng();
+        self.recursive_backtrack(start, &mut visited, &mut rng);
+    }
+
+    fn recursive_backtrack(
+        &mut self,
+        current: Hex,
+        visited: &mut HashSet<Hex>,
+        rng: &mut ThreadRng,
+    ) {
+        visited.insert(current);
+
+        let mut directions = EdgeDirection::ALL_DIRECTIONS;
+        directions.shuffle(rng);
+
+        for direction in directions {
+            let neighbor = current + direction;
+
+            if let Some(_) = self.get_tile(&neighbor) {
+                if !visited.contains(&neighbor) {
+                    self.remove_tile_wall(&current, direction);
+                    self.remove_tile_wall(&neighbor, direction.const_neg());
+
+                    self.recursive_backtrack(neighbor, visited, rng);
+                }
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use hexx::HexLayout;
+
+    use super::*;
+
+    #[test]
+    fn backtracking_generation() {
+        let mut maze = HexMaze::default().with_radius(2);
+
+        // Before generation
+        for tile in maze.tiles.values() {
+            assert_eq!(tile.walls.as_bits(), 0b111111);
+        }
+
+        // Generate using backtracking
+        maze.generate(GeneratorType::BackTracking);
+
+        // After generation
+        let all_walls = maze
+            .tiles
+            .values()
+            .all(|tile| tile.walls.as_bits() == 0b111111);
+        assert!(!all_walls, "Some walls should be removed");
+    }
+
+    #[test]
+    fn empty_maze() {
+        let mut maze = HexMaze::with_layout(HexLayout::default());
+        maze.generate(GeneratorType::BackTracking);
+        assert!(maze.is_empty(), "Empty maze should remain empty");
+    }
+}

src/lib.rs

@@ -1,3 +1,4 @@
+mod generator;
 mod maze;
 mod tile;
 mod walls;

src/maze.rs

@@ -8,7 +8,7 @@ use super::{HexTile, Walls};
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 #[derive(Debug, Clone, Default)]
 pub struct HexMaze {
-    tiles: HashMap<Hex, HexTile>,
+    pub tiles: HashMap<Hex, HexTile>,
     layout: HexLayout,
 }
 
@@ -83,8 +83,8 @@ impl HexMaze {
 
     /// Returns an iterator over all tiles
     #[inline]
-    pub fn tiles(&self) -> impl Iterator<Item = (&Hex, &HexTile)> {
+    pub fn tiles(&self) -> &HashMap<Hex, HexTile> {
-        self.tiles.iter()
+        &self.tiles
     }
 
     /// Returns the number of tiles in the maze
@@ -98,6 +98,13 @@ impl HexMaze {
     pub fn is_empty(&self) -> bool {
         self.tiles.is_empty()
     }
+
+    #[inline]
+    pub fn remove_tile_wall(&mut self, coord: &Hex, direction: EdgeDirection) {
+        if let Some(tile) = self.tiles.get_mut(coord) {
+            tile.walls.remove(direction);
+        }
+    }
 }
 
 #[cfg(test)]
@@ -165,7 +172,11 @@ mod tests {
         }
 
         // Test iterator
-        let collected = maze.tiles().map(|(_, tile)| tile).collect::<Vec<_>>();
+        let collected = maze
+            .tiles()
+            .iter()
+            .map(|(_, tile)| tile)
+            .collect::<Vec<_>>();
         assert_eq!(
             collected.len(),
             coords.len(),
@@ -248,7 +259,11 @@ mod tests {
         }
 
         // Verify iterator
-        let iter_coords = maze.tiles().map(|(coord, _)| *coord).collect::<Vec<_>>();
+        let iter_coords = maze
+            .tiles()
+            .iter()
+            .map(|(coord, _)| *coord)
+            .collect::<Vec<_>>();
         assert_eq!(
             iter_coords.len(),
             coords.len(),

src/walls.rs

@@ -17,13 +17,13 @@ impl Walls {
     /// Adds a wall in the specified direction
     #[inline]
     pub fn add(&mut self, direction: EdgeDirection) {
-        self.0 |= Self::from(direction).0
+        self.0 |= Self::from(direction).0;
     }
 
     /// Removes a wall in the specified direction
     #[inline]
     pub fn remove(&mut self, direction: EdgeDirection) {
-        self.0 &= !Self::from(direction).0
+        self.0 &= !Self::from(direction).0;
     }
 
     /// Returns true if there is a wall in the specified direction