Generate map with cellular automata, completes section 4.5

src/components.rs

@@ -5,7 +5,7 @@ use specs::prelude::*;
 use specs::saveload::{ConvertSaveload, Marker};
 use specs_derive::*;
 
-#[derive(Component, ConvertSaveload, Copy, Clone)]
+#[derive(Component, ConvertSaveload, Default, Copy, Clone)]
 pub struct Position {
     pub x: i32,
     pub y: i32,

src/map_builders/cellular_automata.rs

@@ -0,0 +1,196 @@
+use super::MapBuilder;
+use crate::{components::Position, spawner, Map, TileType, SHOW_MAPGEN_VISUALIZER};
+use rltk::RandomNumberGenerator;
+use specs::prelude::*;
+use std::collections::HashMap;
+
+pub struct CellularAutomataBuilder {
+    map: Map,
+    starting_position: Position,
+    depth: i32,
+    history: Vec<Map>,
+    noise_areas: HashMap<i32, Vec<usize>>,
+}
+
+impl MapBuilder for CellularAutomataBuilder {
+    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 CellularAutomataBuilder {
+    pub fn new(new_depth: i32) -> CellularAutomataBuilder {
+        CellularAutomataBuilder {
+            map: Map::new(new_depth),
+            starting_position: Position::default(),
+            depth: new_depth,
+            history: Vec::new(),
+            noise_areas: HashMap::new(),
+        }
+    }
+
+    fn build(&mut self) {
+        let mut rng = RandomNumberGenerator::new();
+
+        // First we completely randomize the map, setting 55% of it to be floor.
+        for y in 1..self.map.height - 1 {
+            for x in 1..self.map.width - 1 {
+                let roll = rng.roll_dice(1, 100);
+                let idx = self.map.xy_idx(x, y);
+
+                if roll > 55 {
+                    self.map.tiles[idx] = TileType::Floor
+                } else {
+                    self.map.tiles[idx] = TileType::Wall
+                }
+            }
+        }
+
+        self.take_snapshot();
+
+        // Now we iteratively apply cellular automata rules
+        for _i in 0..15 {
+            let mut newtiles = self.map.tiles.clone();
+
+            for y in 1..self.map.height - 1 {
+                for x in 1..self.map.width - 1 {
+                    let idx = self.map.xy_idx(x, y);
+                    let mut neighbors = 0;
+
+                    if self.map.tiles[idx - 1] == TileType::Wall {
+                        neighbors += 1;
+                    }
+                    if self.map.tiles[idx + 1] == TileType::Wall {
+                        neighbors += 1;
+                    }
+                    if self.map.tiles[idx - self.map.width as usize] == TileType::Wall {
+                        neighbors += 1;
+                    }
+                    if self.map.tiles[idx + self.map.width as usize] == TileType::Wall {
+                        neighbors += 1;
+                    }
+                    if self.map.tiles[idx - (self.map.width as usize - 1)] == TileType::Wall {
+                        neighbors += 1;
+                    }
+                    if self.map.tiles[idx - (self.map.width as usize + 1)] == TileType::Wall {
+                        neighbors += 1;
+                    }
+                    if self.map.tiles[idx + (self.map.width as usize - 1)] == TileType::Wall {
+                        neighbors += 1;
+                    }
+                    if self.map.tiles[idx + (self.map.width as usize + 1)] == TileType::Wall {
+                        neighbors += 1;
+                    }
+
+                    if neighbors > 4 || neighbors == 0 {
+                        newtiles[idx] = TileType::Wall;
+                    } else {
+                        newtiles[idx] = TileType::Floor;
+                    }
+                }
+            }
+
+            self.map.tiles = newtiles.clone();
+            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)
+        }
+
+        // Find all tiles we can reach from the starting point
+        let map_starts: Vec<usize> = vec![start_idx];
+        let dijkstra_map = rltk::DijkstraMap::new(
+            self.map.width,
+            self.map.height,
+            &map_starts,
+            &self.map,
+            200.0,
+        );
+        let mut exit_tile = (0, 0.0f32);
+        for (i, tile) in self.map.tiles.iter_mut().enumerate() {
+            if *tile == TileType::Floor {
+                let distance_to_start = dijkstra_map.map[i];
+
+                // We can't get to this tile - so we'll make it a wall
+                if distance_to_start == f32::MAX {
+                    *tile = TileType::Wall;
+                } else {
+                    // If it is further away than our current exit candidate, move the exit
+                    if distance_to_start > exit_tile.1 {
+                        exit_tile.0 = i;
+                        exit_tile.1 = distance_to_start;
+                    }
+                }
+            }
+        }
+        self.take_snapshot();
+
+        // Place the stairs
+        self.map.tiles[exit_tile.0] = TileType::DownStairs;
+        self.take_snapshot();
+
+        // Now we build a noise map for use in spawning entities later
+        let mut noise = rltk::FastNoise::seeded(rng.roll_dice(1, 65536) as u64);
+        noise.set_noise_type(rltk::NoiseType::Cellular);
+        noise.set_frequency(0.08);
+        noise.set_cellular_distance_function(rltk::CellularDistanceFunction::Manhattan);
+
+        for y in 1..self.map.height - 1 {
+            for x in 1..self.map.width - 1 {
+                let idx = self.map.xy_idx(x, y);
+                if self.map.tiles[idx] == TileType::Floor {
+                    let cell_value_f = noise.get_noise(x as f32, y as f32) * 10240.0;
+                    let cell_value = cell_value_f as i32;
+
+                    #[allow(clippy::map_entry)]
+                    if self.noise_areas.contains_key(&cell_value) {
+                        self.noise_areas.get_mut(&cell_value).unwrap().push(idx);
+                    } else {
+                        self.noise_areas.insert(cell_value, vec![idx]);
+                    }
+                }
+            }
+        }
+    }
+}

src/map_builders/mod.rs

@@ -1,11 +1,13 @@
 mod bsp_dungeon;
 mod bsp_interior;
+mod cellular_automata;
 mod common;
 mod simple_map;
 
 use crate::{Map, Position};
 use bsp_dungeon::BspDungeonBuilder;
 use bsp_interior::BspInteriorBuilder;
+use cellular_automata::CellularAutomataBuilder;
 use common::*;
 use simple_map::SimpleMapBuilder;
 use specs::prelude::*;
@@ -21,9 +23,10 @@ pub trait MapBuilder {
 
 pub fn random_builder(new_depth: i32) -> Box<dyn MapBuilder> {
     let mut rng = rltk::RandomNumberGenerator::new();
-    match rng.roll_dice(1, 3) {
+    match rng.roll_dice(1, 4) {
         1 => Box::new(BspDungeonBuilder::new(new_depth)),
         2 => Box::new(BspInteriorBuilder::new(new_depth)),
+        3 => Box::new(CellularAutomataBuilder::new(new_depth)),
         _ => Box::new(SimpleMapBuilder::new(new_depth)),
     }
 }

src/spawner.rs

@@ -1,5 +1,5 @@
 use crate::components::*;
-use crate::{map::MAP_WIDTH, random_table::RandomTable, Rect};
+use crate::{map::MAP_WIDTH, random_table::RandomTable, Map, Rect, TileType};
 use rltk::{RandomNumberGenerator, RGB};
 use specs::prelude::*;
 use specs::saveload::{MarkedBuilder, SimpleMarker};
@@ -57,35 +57,61 @@ fn room_table(map_depth: i32) -> RandomTable {
 /// fills a room with stuff!
 #[allow(clippy::map_entry)]
 pub fn spawn_room(ecs: &mut World, room: &Rect, map_depth: i32) {
+    let mut possible_targets: Vec<usize> = Vec::new();
+
+    // Borrow scope - to keep access to the map separated
+    {
+        let map = ecs.fetch::<Map>();
+        for y in room.y1 + 1..room.y2 {
+            for x in room.x1 + 1..room.x2 {
+                let idx = map.xy_idx(x, y);
+                if map.tiles[idx] == TileType::Floor {
+                    possible_targets.push(idx);
+                }
+            }
+        }
+    }
+
+    spawn_region(ecs, &possible_targets, map_depth);
+}
+
+pub fn spawn_region(ecs: &mut World, area: &[usize], map_depth: i32) {
     let spawn_table = room_table(map_depth);
     let mut spawn_points: HashMap<usize, String> = HashMap::new();
+    let mut areas: Vec<usize> = Vec::from(area);
 
     // Scope to keep the borrow checker happy
     {
         let mut rng = ecs.write_resource::<RandomNumberGenerator>();
-        let num_spawns = rng.roll_dice(1, MAX_MONSTERS + 3) + (map_depth - 1) - 3;
+        let num_spawns = i32::min(
+            areas.len() as i32,
+            rng.roll_dice(1, MAX_MONSTERS + 3) + (map_depth - 1) - 3,
+        );
+
+        if num_spawns == 0 {
+            return;
+        }
 
         for _i in 0..num_spawns {
-            let mut added = false;
+            let array_index = if areas.len() == 1 {
-            let mut tries = 0;
+                0usize
-
-            while !added && tries < 20 {
-                let x = (room.x1 + rng.roll_dice(1, i32::abs(room.x2 - room.x1))) as usize;
-                let y = (room.y1 + rng.roll_dice(1, i32::abs(room.y2 - room.y1))) as usize;
-                let idx = (y * MAP_WIDTH) + x;
-
-                if !spawn_points.contains_key(&idx) {
-                    spawn_points.insert(idx, spawn_table.roll(&mut rng));
-                    added = true;
             } else {
-                    tries += 1;
+                (rng.roll_dice(1, areas.len() as i32) - 1) as usize
-                }
+            };
-            }
+            let map_idx = areas[array_index];
+            spawn_points.insert(map_idx, spawn_table.roll(&mut rng));
+            areas.remove(array_index);
         }
     }
 
-    // Actually spawn stuff
+    // Actually spawn the monsters
     for spawn in spawn_points.iter() {
+        spawn_entity(ecs, &spawn);
+    }
+}
+
+/// Spawns a named entity (name in tuple.1) at the location in (tuple.0)
+fn spawn_entity(ecs: &mut World, spawn: &(&usize, &String)) {
     let x = (*spawn.0 % MAP_WIDTH) as i32;
     let y = (*spawn.0 / MAP_WIDTH) as i32;
 
@@ -105,7 +131,6 @@ pub fn spawn_room(ecs: &mut World, room: &Rect, map_depth: i32) {
         "Bear Trap" => bear_trap(ecs, x, y),
         _ => {}
     }
-    }
 }
 
 fn orc(ecs: &mut World, x: i32, y: i32) {