Complete section 4.10

src/map_builders/mod.rs

@@ -6,6 +6,7 @@ mod dla;
 mod drunkard;
 mod maze;
 mod simple_map;
+mod voronoi;
 
 use crate::{Map, Position};
 use bsp_dungeon::BspDungeonBuilder;
@@ -17,6 +18,7 @@ use drunkard::DrunkardsWalkBuilder;
 use maze::MazeBuilder;
 use simple_map::SimpleMapBuilder;
 use specs::prelude::*;
+use voronoi::VoronoiCellBuilder;
 
 pub trait MapBuilder {
     fn build_map(&mut self);
@@ -29,7 +31,7 @@ pub trait MapBuilder {
 
 pub fn random_builder(new_depth: i32) -> Box<dyn MapBuilder> {
     let mut rng = rltk::RandomNumberGenerator::new();
-    match rng.roll_dice(1, 14) {
+    match rng.roll_dice(1, 16) {
         1 => Box::new(BspDungeonBuilder::new(new_depth)),
         2 => Box::new(BspInteriorBuilder::new(new_depth)),
         3 => Box::new(CellularAutomataBuilder::new(new_depth)),
@@ -43,6 +45,8 @@ pub fn random_builder(new_depth: i32) -> Box<dyn MapBuilder> {
         11 => Box::new(DLABuilder::walk_outwards(new_depth)),
         12 => Box::new(DLABuilder::central_attractor(new_depth)),
         13 => Box::new(DLABuilder::insectoid(new_depth)),
+        14 => Box::new(VoronoiCellBuilder::pythagoras(new_depth)),
+        15 => Box::new(VoronoiCellBuilder::manhattan(new_depth)),
         _ => Box::new(SimpleMapBuilder::new(new_depth)),
     }
 }

src/map_builders/voronoi.rs

@@ -0,0 +1,187 @@
+use super::common::{
+    generate_voronoi_spawn_regions, remove_unreachable_areas_returning_most_distant,
+};
+use super::MapBuilder;
+use crate::{components::Position, spawner, Map, TileType, SHOW_MAPGEN_VISUALIZER};
+use rltk::RandomNumberGenerator;
+use specs::prelude::*;
+use std::collections::HashMap;
+
+#[derive(PartialEq, Copy, Clone)]
+#[allow(dead_code)]
+pub enum DistanceAlgorithm {
+    Pythagoras,
+    Manhattan,
+    Chebyshev,
+}
+
+pub struct VoronoiCellBuilder {
+    map: Map,
+    starting_position: Position,
+    depth: i32,
+    history: Vec<Map>,
+    noise_areas: HashMap<i32, Vec<usize>>,
+    n_seeds: usize,
+    distance_algorithm: DistanceAlgorithm,
+}
+
+impl MapBuilder for VoronoiCellBuilder {
+    fn build_map(&mut self) {
+        self.build();
+    }
+
+    fn spawn_entities(&mut self, ecs: &mut World) {
+        for area in self.noise_areas.iter() {
+            spawner::spawn_region(ecs, area.1, self.depth);
+        }
+    }
+
+    fn get_map(&self) -> Map {
+        self.map.clone()
+    }
+
+    fn get_starting_position(&self) -> Position {
+        self.starting_position
+    }
+
+    fn get_snapshot_history(&self) -> Vec<Map> {
+        self.history.clone()
+    }
+
+    fn take_snapshot(&mut self) {
+        if SHOW_MAPGEN_VISUALIZER {
+            let mut snapshot = self.map.clone();
+            for v in snapshot.revealed_tiles.iter_mut() {
+                *v = true;
+            }
+            self.history.push(snapshot);
+        }
+    }
+}
+
+impl VoronoiCellBuilder {
+    pub fn new(new_depth: i32) -> VoronoiCellBuilder {
+        VoronoiCellBuilder {
+            map: Map::new(new_depth),
+            starting_position: Position::default(),
+            depth: new_depth,
+            history: Vec::new(),
+            noise_areas: HashMap::new(),
+            n_seeds: 64,
+            distance_algorithm: DistanceAlgorithm::Pythagoras,
+        }
+    }
+
+    pub fn pythagoras(new_depth: i32) -> VoronoiCellBuilder {
+        VoronoiCellBuilder::new(new_depth)
+    }
+
+    pub fn manhattan(new_depth: i32) -> VoronoiCellBuilder {
+        VoronoiCellBuilder {
+            distance_algorithm: DistanceAlgorithm::Manhattan,
+            ..VoronoiCellBuilder::new(new_depth)
+        }
+    }
+
+    #[allow(clippy::map_entry)]
+    fn build(&mut self) {
+        let mut rng = RandomNumberGenerator::new();
+
+        // Make a Voronoi diagram. We'll do this the hard way to learn about the technique!
+        let mut voronoi_seeds: Vec<(usize, rltk::Point)> = Vec::new();
+
+        while voronoi_seeds.len() < self.n_seeds {
+            let vx = rng.roll_dice(1, self.map.width - 1);
+            let vy = rng.roll_dice(1, self.map.height - 1);
+            let vidx = self.map.xy_idx(vx, vy);
+            let candidate = (vidx, rltk::Point::new(vx, vy));
+            if !voronoi_seeds.contains(&candidate) {
+                voronoi_seeds.push(candidate);
+            }
+        }
+
+        let mut voronoi_distance = vec![(0, 0.0f32); self.n_seeds];
+        let mut voronoi_membership: Vec<i32> =
+            vec![0; self.map.width as usize * self.map.height as usize];
+        for (i, vid) in voronoi_membership.iter_mut().enumerate() {
+            let x = i as i32 % self.map.width;
+            let y = i as i32 / self.map.width;
+
+            for (seed, pos) in voronoi_seeds.iter().enumerate() {
+                let distance;
+                match self.distance_algorithm {
+                    DistanceAlgorithm::Pythagoras => {
+                        distance = rltk::DistanceAlg::PythagorasSquared
+                            .distance2d(rltk::Point::new(x, y), pos.1);
+                    }
+                    DistanceAlgorithm::Manhattan => {
+                        distance =
+                            rltk::DistanceAlg::Manhattan.distance2d(rltk::Point::new(x, y), pos.1);
+                    }
+                    DistanceAlgorithm::Chebyshev => {
+                        distance =
+                            rltk::DistanceAlg::Chebyshev.distance2d(rltk::Point::new(x, y), pos.1);
+                    }
+                }
+                voronoi_distance[seed] = (seed, distance);
+            }
+
+            voronoi_distance.sort_by(|a, b| a.1.partial_cmp(&b.1).unwrap());
+
+            *vid = voronoi_distance[0].0 as i32;
+        }
+
+        for y in 1..self.map.height - 1 {
+            for x in 1..self.map.width - 1 {
+                let mut neighbors = 0;
+                let my_idx = self.map.xy_idx(x, y);
+                let my_seed = voronoi_membership[my_idx];
+
+                if voronoi_membership[self.map.xy_idx(x - 1, y)] != my_seed {
+                    neighbors += 1;
+                }
+                if voronoi_membership[self.map.xy_idx(x + 1, y)] != my_seed {
+                    neighbors += 1;
+                }
+                if voronoi_membership[self.map.xy_idx(x, y - 1)] != my_seed {
+                    neighbors += 1;
+                }
+                if voronoi_membership[self.map.xy_idx(x, y + 1)] != my_seed {
+                    neighbors += 1;
+                }
+
+                if neighbors < 2 {
+                    self.map.tiles[my_idx] = TileType::Floor;
+                }
+            }
+            self.take_snapshot();
+        }
+
+        // Find a starting point; start at the middle and walk left until we find an open tile
+        self.starting_position = Position {
+            x: self.map.width / 2,
+            y: self.map.height / 2,
+        };
+        let mut start_idx = self
+            .map
+            .xy_idx(self.starting_position.x, self.starting_position.y);
+        while self.map.tiles[start_idx] != TileType::Floor {
+            self.starting_position.x -= 1;
+            start_idx = self
+                .map
+                .xy_idx(self.starting_position.x, self.starting_position.y);
+        }
+        self.take_snapshot();
+
+        // Find all tiles we can reach from the starting point
+        let exit_tile = remove_unreachable_areas_returning_most_distant(&mut self.map, start_idx);
+        self.take_snapshot();
+
+        // Place the stairs
+        self.map.tiles[exit_tile] = TileType::DownStairs;
+        self.take_snapshot();
+
+        // Now we build a noise map for use in spawning entities later
+        self.noise_areas = generate_voronoi_spawn_regions(&self.map, &mut rng);
+    }
+}