Remove unreachable areas

README.md

@@ -36,7 +36,7 @@ If you want to check how the maps look like, then:
     * [ ] Area exit point
     * [x] Area starting point
     * [x] Cellular automata
-    * [ ] Cull unreachable areas
+    * [x] Cull unreachable areas
     * [ ] Voronoi spawning
 
 
@@ -61,6 +61,21 @@ let gen = CellularAutomataGen::new(80, 50);
 let map = gen.generate_map(&mut rng)
 ```
 
+Use MapBuilder for chaining map generator and modifiers
+
+```rust
+use mapgen::dungeon::{
+    MapBuilder,
+    map::{Map, Point, TileType},
+    cellular_automata::CellularAutomataGen,
+    starting_point::{AreaStartingPosition, XStart, YStart},
+};
+
+let map = MapBuilder::new(Box::new(CellularAutomataGen::new(80, 50)))
+            .with(AreaStartingPosition::new(XStart::CENTER, YStart::CENTER))
+            .build_map();
+```
+
 For more information check the [doc](https://docs.rs/mapgen)
 
 # License

demo/src/main.rs

@@ -25,6 +25,7 @@ use mapgen::dungeon::{
     map::{Map, Point, TileType},
     cellular_automata::CellularAutomataGen,
     starting_point::{AreaStartingPosition, XStart, YStart},
+    cull_unreachable::CullUnreachable,
 };
 
 
@@ -83,6 +84,7 @@ fn init_camera(world: &mut World, transform: Transform, camera: Camera) -> Entit
 fn init_map(world: &mut World) {
     let map = MapBuilder::new(Box::new(CellularAutomataGen::new(80, 50)))
         .with(AreaStartingPosition::new(XStart::CENTER, YStart::CENTER))
+        .with(CullUnreachable::new())
         .build_map();
     world.insert(map); 
 }

src/dungeon/cull_unreachable.rs

@@ -0,0 +1,71 @@
+use rand::prelude::StdRng;
+use super::MapModifier;
+use super::map::{Map, TileType};
+use super::dijkstra::DijkstraMap;
+
+
+pub struct CullUnreachable {}
+
+impl MapModifier for CullUnreachable {
+    fn modify_map(&self, _: &mut StdRng, map: &Map)  -> Map {
+        self.build(map)
+    }
+}
+
+impl CullUnreachable {
+    #[allow(dead_code)]
+    pub fn new() -> Box<CullUnreachable> {
+        Box::new(CullUnreachable{})
+    }
+
+    fn build(&self, map: &Map) -> Map {
+        let mut new_map = map.clone();
+
+        let dijkstra_map = DijkstraMap::new(map);
+        for (i, tile) in new_map.tiles.iter_mut().enumerate() {
+            if *tile == TileType::Floor {
+                let distance_to_start = dijkstra_map.tiles[i];
+                // We can't get to this tile - so we'll make it a wall
+                if distance_to_start == std::f32::MAX {
+                    *tile = TileType::Wall;
+                }
+            }
+        }
+        new_map
+    }
+}
+
+/// ------------------------------------------------------------------------------------------------
+/// Module unit tests
+/// ------------------------------------------------------------------------------------------------
+#[cfg(test)]
+mod tests {
+    use rand::prelude::*;
+    use super::*;
+    use super::MapModifier;
+    use crate::dungeon::map::{Point, Map};
+
+    #[test]
+    fn test_culling() {
+        let map_str = "
+        ##########
+        #  #     #
+        ##########
+        ";
+        let mut map = Map::from_string(map_str);
+        map.starting_point = Some(Point::new(9, 1));
+        let expected_map_str = "
+        ##########
+        ####     #
+        ##########
+        ";
+        let expected_map = Map::from_string(expected_map_str);
+
+
+        let modifier = CullUnreachable::new();
+        let mut rng = StdRng::seed_from_u64(0);
+        let new_map = modifier.modify_map(&mut rng, &map);
+
+        assert_eq!(new_map.tiles, expected_map.tiles);
+    }
+}

src/dungeon/dijkstra copy.rs

@@ -0,0 +1,271 @@
+use std::collections::VecDeque;
+use std::f32::MAX;
+
+/// Representation of a Dijkstra flow map.
+/// map is a vector of floats, having a size equal to size_x * size_y (one per tile).
+/// size_x and size_y are stored for overflow avoidance.
+/// max_depth is the maximum number of iterations this search shall support.
+pub struct DijkstraMap {
+    pub map: Vec<f32>,
+    size_x: usize,
+    size_y: usize,
+    max_depth: f32,
+}
+
+impl DijkstraMap {
+    /// Construct a new Dijkstra map, ready to run. You must specify the map size, and link to an implementation
+    /// of a BaseMap trait that can generate exits lists. It then builds the map, giving you a result.
+    pub fn new<T>(
+        size_x: T,
+        size_y: T,
+        starts: &[usize],
+        map: &dyn BaseMap,
+        max_depth: f32,
+    ) -> DijkstraMap
+    where
+        T: TryInto<usize>,
+    {
+        let sz_x: usize = size_x.try_into().ok().unwrap();
+        let sz_y: usize = size_y.try_into().ok().unwrap();
+        let result: Vec<f32> = vec![MAX; sz_x * sz_y];
+        let mut d = DijkstraMap {
+            map: result,
+            size_x: sz_x,
+            size_y: sz_y,
+            max_depth,
+        };
+        DijkstraMap::build(&mut d, starts, map);
+        d
+    }
+
+    /// Creates an empty Dijkstra map node.
+    pub fn new_empty<T>(size_x: T, size_y: T, max_depth: f32) -> DijkstraMap
+    where
+        T: TryInto<usize>,
+    {
+        let sz_x: usize = size_x.try_into().ok().unwrap();
+        let sz_y: usize = size_y.try_into().ok().unwrap();
+        let result: Vec<f32> = vec![MAX; sz_x * sz_y];
+        DijkstraMap {
+            map: result,
+            size_x: sz_x,
+            size_y: sz_y,
+            max_depth,
+        }
+    }
+
+    /// Clears the Dijkstra map. Uses a parallel for each for performance.
+    #[cfg(feature = "threaded")]
+    pub fn clear(dm: &mut DijkstraMap) {
+        dm.map.par_iter_mut().for_each(|x| *x = MAX);
+    }
+
+    #[cfg(not(feature = "threaded"))]
+    pub fn clear(dm: &mut DijkstraMap) {
+        dm.map.iter_mut().for_each(|x| *x = MAX);
+    }
+
+    #[cfg(feature = "threaded")]
+    fn build_helper(dm: &mut DijkstraMap, starts: &[usize], map: &dyn BaseMap) -> RunThreaded {
+        if starts.len() >= THREADED_REQUIRED_STARTS {
+            DijkstraMap::build_parallel(dm, starts, map);
+            return RunThreaded::True;
+        }
+        RunThreaded::False
+    }
+
+    #[cfg(not(feature = "threaded"))]
+    fn build_helper(_dm: &mut DijkstraMap, _starts: &[usize], _map: &dyn BaseMap) -> RunThreaded {
+        RunThreaded::False
+    }
+
+    /// Builds the Dijkstra map: iterate from each starting point, to each exit provided by BaseMap's
+    /// exits implementation. Each step adds cost to the current depth, and is discarded if the new
+    /// depth is further than the current depth.
+    /// WARNING: Will give incorrect results when used with non-uniform exit costs. Much slower
+    /// algorithm required to support that.
+    /// Automatically branches to a parallel version if you provide more than 4 starting points
+    pub fn build(dm: &mut DijkstraMap, starts: &[usize], map: &dyn BaseMap) {
+        let threaded = DijkstraMap::build_helper(dm, starts, map);
+        if threaded == RunThreaded::True { return; }
+        let mapsize: usize = (dm.size_x * dm.size_y) as usize;
+        let mut open_list: VecDeque<(usize, f32)> = VecDeque::with_capacity(mapsize);
+
+        for start in starts {
+            open_list.push_back((*start, 0.0));
+        }
+
+        while let Some((tile_idx, depth)) = open_list.pop_front() {
+            let exits = map.get_available_exits(tile_idx);
+            for (new_idx, add_depth) in exits {
+                let new_depth = depth + add_depth;
+                let prev_depth = dm.map[new_idx];
+                if new_depth >= prev_depth { continue; }
+                if new_depth >= dm.max_depth { continue; }
+                dm.map[new_idx] = new_depth;
+                open_list.push_back((new_idx, new_depth));
+            }
+        }
+    }
+
+    /// Implementation of Parallel Dijkstra.
+    #[cfg(feature = "threaded")]
+    fn build_parallel(dm: &mut DijkstraMap, starts: &[usize], map: &dyn BaseMap) {
+        let mapsize: usize = (dm.size_x * dm.size_y) as usize;
+        let mut layers: Vec<ParallelDm> = Vec::with_capacity(starts.len());
+        for start_chunk in starts.chunks(rayon::current_num_threads()) {
+            let mut layer = ParallelDm {
+                map: vec![MAX; mapsize],
+                max_depth: dm.max_depth,
+                starts: Vec::new(),
+            };
+            layer
+                .starts
+                .extend(start_chunk.iter().copied().map(|x| x as usize));
+            layers.push(layer);
+        }
+
+        let exits: Vec<SmallVec<[(usize, f32); 10]>> = (0..mapsize)
+            .map(|idx| map.get_available_exits(idx))
+            .collect();
+
+        // Run each map in parallel
+        layers.par_iter_mut().for_each(|l| {
+            let mut open_list: VecDeque<(usize, f32)> = VecDeque::with_capacity(mapsize);
+
+            for start in l.starts.iter().copied() {
+                open_list.push_back((start, 0.0));
+            }
+
+            while let Some((tile_idx, depth)) = open_list.pop_front() {
+                let exits = &exits[tile_idx];
+                for (new_idx, add_depth) in exits {
+                    let new_idx = *new_idx;
+                    let new_depth = depth + add_depth;
+                    let prev_depth = l.map[new_idx];
+                    if new_depth >= prev_depth { continue; }
+                    if new_depth >= l.max_depth { continue; }
+                    l.map[new_idx] = new_depth;
+                    open_list.push_back((new_idx, new_depth));
+                }
+            }
+
+        });
+
+        // Recombine down to a single result
+        for l in layers {
+            for i in 0..mapsize {
+                dm.map[i] = f32::min(dm.map[i], l.map[i]);
+            }
+        }
+    }
+
+    /// Helper for traversing maps as path-finding. Provides the index of the lowest available
+    /// exit from the specified position index, or None if there isn't one.
+    /// You would use this for pathing TOWARDS a starting node.
+    #[cfg(feature = "threaded")]
+    pub fn find_lowest_exit(dm: &DijkstraMap, position: usize, map: &dyn BaseMap) -> Option<usize> {
+        let mut exits = map.get_available_exits(position);
+
+        if exits.is_empty() {
+            return None;
+        }
+
+        exits.par_sort_by(|a, b| {
+            dm.map[a.0 as usize]
+                .partial_cmp(&dm.map[b.0 as usize])
+                .unwrap()
+        });
+
+        Some(exits[0].0)
+    }
+
+    #[cfg(not(feature = "threaded"))]
+    pub fn find_lowest_exit(dm: &DijkstraMap, position: usize, map: &dyn BaseMap) -> Option<usize> {
+        let mut exits = map.get_available_exits(position);
+
+        if exits.is_empty() {
+            return None;
+        }
+
+        exits.sort_by(|a, b| {
+            dm.map[a.0 as usize]
+                .partial_cmp(&dm.map[b.0 as usize])
+                .unwrap()
+        });
+
+        Some(exits[0].0)
+    }
+
+    /// Helper for traversing maps as path-finding. Provides the index of the highest available
+    /// exit from the specified position index, or None if there isn't one.
+    /// You would use this for pathing AWAY from a starting node, for example if you are running
+    /// away.
+    #[cfg(feature = "threaded")]
+    pub fn find_highest_exit(
+        dm: &DijkstraMap,
+        position: usize,
+        map: &dyn BaseMap,
+    ) -> Option<usize> {
+        let mut exits = map.get_available_exits(position);
+
+        if exits.is_empty() {
+            return None;
+        }
+
+        exits.par_sort_by(|a, b| {
+            dm.map[b.0 as usize]
+                .partial_cmp(&dm.map[a.0 as usize])
+                .unwrap()
+        });
+
+        Some(exits[0].0)
+    }
+
+    #[cfg(not(feature = "threaded"))]
+    pub fn find_highest_exit(
+        dm: &DijkstraMap,
+        position: usize,
+        map: &dyn BaseMap,
+    ) -> Option<usize> {
+        let mut exits = map.get_available_exits(position);
+
+        if exits.is_empty() {
+            return None;
+        }
+
+        exits.sort_by(|a, b| {
+            dm.map[b.0 as usize]
+                .partial_cmp(&dm.map[a.0 as usize])
+                .unwrap()
+        });
+
+        Some(exits[0].0)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::prelude::*;
+    use bracket_algorithm_traits::prelude::*;
+    // 1 by 3 stripe of tiles
+    struct MiniMap;
+    impl BaseMap for MiniMap {
+        fn get_available_exits(&self, idx: usize) -> SmallVec<[(usize, f32); 10]> {
+            match idx {
+                0 => smallvec![(1, 1.)],
+                2 => smallvec![(1, 1.)],
+                _ => smallvec![(idx - 1, 1.), (idx + 1, 2.)],
+            }
+        }
+    }
+    #[test]
+    fn test_highest_exit() {
+        let map = MiniMap {};
+        let exits_map = DijkstraMap::new(3, 1, &[0], &map, 10.);
+        let target = DijkstraMap::find_highest_exit(&exits_map, 0, &map);
+        assert_eq!(target, Some(1));
+        let target = DijkstraMap::find_highest_exit(&exits_map, 1, &map);
+        assert_eq!(target, Some(2));
+    }
+}

src/dungeon/dijkstra.rs

@@ -0,0 +1,126 @@
+//! Calculate Dijkstra influence map
+//! 
+//! http://www.roguebasin.com/index.php?title=The_Incredible_Power_of_Dijkstra_Maps
+//! 
+//! This algorithm calculates cost (distance) of moving from the given starting point
+//! to the each point on the map. Point which are not reachable will get f32::MAX value.
+//! 
+//! Example generator usage:
+//! ---
+//! use rand::prelude::*;
+//! use mapgen::dungeon::{
+//!     MapModifier,
+//!     map::{Map, Point, TileType},
+//!     starting_point::{AreaStartingPosition, XStart, YStart}
+//! };
+//! 
+//! let mut rng = StdRng::seed_from_u64(100);
+//! let mut map = Map::new(80, 50);
+//! map.set_tile(10, 10, TileType::Floor);
+//! let modifier = AreaStartingPosition::new(XStart::LEFT, YStart::TOP);
+//! let new_map = modifier.modify_map(&mut rng, &map);
+//! 
+//! assert_eq!(new_map.starting_point, Some(Point::new(10, 10)));
+//! ---
+//! 
+
+use std::collections::VecDeque;
+use std::f32::MAX;
+use super::map::Map;
+
+
+/// Representation of a Dijkstra flow map.
+/// map is a vector of floats, having a size equal to size_x * size_y (one per tile).
+/// size_x and size_y are stored for overflow avoidance.
+/// max_depth is the maximum number of iterations this search shall support.
+pub struct DijkstraMap {
+    pub tiles: Vec<f32>,
+    size_x: usize,
+    size_y: usize,
+    max_depth: f32,
+}
+
+impl DijkstraMap {
+    /// Construct a new Dijkstra map, ready to run. You must specify the map size, and link to an implementation
+    /// of a BaseMap trait that can generate exits lists. It then builds the map, giving you a result.
+    pub fn new(map: &Map) -> DijkstraMap {
+        let len =  map.width * map.height;
+        let tiles = vec![MAX; len];
+        let mut d = DijkstraMap {
+            tiles: tiles,
+            size_x: map.width,
+            size_y: map.height,
+            max_depth: len as f32,
+        };
+        d.build(map);
+        d
+    }
+
+    /// Builds the Dijkstra map: iterate from each starting point, to each exit provided by BaseMap's
+    /// exits implementation. Each step adds cost to the current depth, and is discarded if the new
+    /// depth is further than the current depth.
+    /// WARNING: Will give incorrect results when used with non-uniform exit costs. Much slower
+    /// algorithm required to support that.
+    /// Automatically branches to a parallel version if you provide more than 4 starting points
+    fn build(self: &mut DijkstraMap, map: &Map) {
+        let mapsize: usize = (self.size_x * self.size_y) as usize;
+        let mut open_list: VecDeque<((usize, usize), f32)> = VecDeque::with_capacity(mapsize);
+
+        if let Some(pos) = map.starting_point {
+            open_list.push_back(((pos.x, pos.y), 0.0));
+        }
+
+        while let Some(((x, y), depth)) = open_list.pop_front() {
+            let exits = map.get_available_exits(x, y);
+            for (x, y, add_depth) in exits {
+                let idx = self.xy_idx(x, y);
+                let new_depth = depth + add_depth;
+                let prev_depth = self.tiles[idx];
+                if new_depth >= prev_depth { continue; }
+                if new_depth >= self.max_depth { continue; }
+                self.tiles[idx] = depth;
+                open_list.push_back(((x, y), new_depth));
+            }
+        }
+    }
+
+    fn xy_idx(&self, x: usize, y: usize) -> usize {
+        (y * self.size_x ) + x 
+    }
+
+
+}
+
+/// ------------------------------------------------------------------------------------------------
+/// Module unit tests
+/// ------------------------------------------------------------------------------------------------
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::dungeon::map::{Point, Map};
+
+    #[test]
+    fn test_culling() {
+        let map_str = "
+        ##########
+        # #      #
+        ##########
+        ";
+        let mut map = Map::from_string(map_str);
+        map.starting_point = Some(Point::new(9, 1));
+        let dm = DijkstraMap::new(&map);
+
+        assert_eq!(dm.size_x, 10);
+        assert_eq!(dm.size_y, 3);
+        for i in 0..10 {
+            assert_eq!(dm.tiles[i], MAX);
+            assert_eq!(dm.tiles[2*dm.size_x + i], MAX);
+            let idx = dm.size_x + i;
+            if i < 3 || i == 9 {
+                assert_eq!(dm.tiles[idx], MAX);
+            } else {
+                assert_eq!(dm.tiles[idx], (8 - i) as f32);
+            }
+        }
+    }
+}

src/dungeon/map.rs

@@ -7,11 +7,14 @@
 //! specific game.
 //! 
 
+use std::fmt;
+
+
 /// Position on the map
 #[derive(PartialEq, Copy, Clone, Debug, Eq, Hash)]
 pub struct Point {
-    x: usize,
-    y: usize
+    pub x: usize,
+    pub y: usize
 }
 
 impl Point {
@@ -58,12 +61,58 @@ impl Map {
         }
     }
 
+    /// Create map from given string
+    pub fn from_string(map_string: &str) -> Map {
+        let lines: Vec<&str> = map_string.split("\n")
+            .map(|l| l.trim())
+            .filter(|l| l.len() > 0)
+            .collect();
+        let cols = lines.iter().map(|l| l.len()).max().get_or_insert(1).to_owned();
+        let rows = lines.len();
+        let mut map = Map::new(cols, rows);
+
+        for i in 0..rows {
+            let line = lines[i].as_bytes();
+            for j in 0..line.len() {
+                if line[j] as char == ' ' {
+                    map.set_tile(j, i, TileType::Floor);
+                }
+            }
+        }
+        map
+    }
+
     /// Get TileType at the given location
     pub fn at(&self, x: usize, y: usize) -> TileType {
         let idx = y * self.width + x;
         self.tiles[idx]
     }
 
+    /// Get available exists from the given tile
+    pub fn get_available_exits(&self, x: usize, y: usize) -> Vec<(usize, usize, f32)> {
+        let mut exits = Vec::new();
+
+        // Cardinal directions
+        if self.is_exit_valid(x-1, y) { exits.push((x-1, y, 1.0)) };
+        if self.is_exit_valid(x+1, y) { exits.push((x+1, y, 1.0)) };
+        if self.is_exit_valid(x, y-1) { exits.push((x, y-1, 1.0)) };
+        if self.is_exit_valid(x, y+1) { exits.push((x, y+1, 1.0)) };
+
+        // Diagonals
+        if self.is_exit_valid(x-1, y-1) { exits.push((x-1, y-1, 1.45)); }
+        if self.is_exit_valid(x+1, y-1) { exits.push((x+1, y-1, 1.45)); }
+        if self.is_exit_valid(x-1, y+1) { exits.push((x-1, y+1, 1.45)); }
+        if self.is_exit_valid(x+1, y+1) { exits.push((x+1, y+1, 1.45)); }
+
+        exits
+    }    
+ 
+    // Check if given tile can be accessed
+    fn is_exit_valid(&self, x:usize, y:usize) -> bool {
+        if x < 1 || x > self.width-1 || y < 1 || y > self.height-1 { return false; }
+        self.at(x, y) == TileType::Floor
+    }
+
     /// Modify tile at the given location
     pub fn set_tile(&mut self, x: usize, y: usize, tile: TileType) {
         let idx = y * self.width + x;
@@ -71,6 +120,19 @@ impl Map {
     }
 }
 
+impl fmt::Display for Map {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for y in 0..self.height {
+            let bytes: Vec<u8> = (0..self.width)
+                .map(|x| if self.at(x, y) == TileType::Wall {'#'} else {' '} as u8)
+                .collect();
+            let line = String::from_utf8(bytes).expect("Can't convert map to string");
+            let _ = write!(f, "{}\n", line);
+        }
+        Ok(())
+    }
+}
+
 /// ------------------------------------------------------------------------------------------------
 /// Module unit tests
 /// ------------------------------------------------------------------------------------------------
@@ -95,4 +157,40 @@ mod tests {
             }
         }
     }
+
+    #[test]
+    fn test_from_string() {
+        let map_str = "
+        ##########
+        #        #
+        ##########
+        ";
+        let map = Map::from_string(map_str);
+
+        assert_eq!(map.width, 10);
+        assert_eq!(map.height, 3);
+        for i in 0..10 {
+            assert_eq!(map.at(i, 0), TileType::Wall);
+            assert_eq!(map.at(i, 2), TileType::Wall);
+            if i == 0 || i == 9 {
+                assert_eq!(map.at(i, 1), TileType::Wall);
+            } else {
+                assert_eq!(map.at(i, 1), TileType::Floor);
+            }
+        }
+    }
+
+    #[test]
+    fn test_exists() {
+        let map_str = "
+        ##########
+        #        #
+        #        #
+        ##########
+        ";
+        let map = Map::from_string(map_str);
+        let exists = map.get_available_exits(1, 1);
+        let expected_exists = vec![(2, 1, 1.0), (1, 2, 1.0), (2, 2, 1.45)];
+        assert_eq!(exists, expected_exists);
+    }
 }

src/dungeon/mod.rs

@@ -27,7 +27,9 @@
 
 pub mod map;
 pub mod cellular_automata;
+pub mod cull_unreachable;
 pub mod starting_point;
+mod dijkstra;
 
 use std::time::{SystemTime, UNIX_EPOCH};
 use rand::prelude::*;