Add a layout solver to the waveform_collapse map builder

src/map_builders/waveform_collapse/mod.rs

@@ -1,12 +1,18 @@
+mod common;
+mod constraints;
 mod image_loader;
-use image_loader::*;
+mod solver;
 
 use super::common::{
     generate_voronoi_spawn_regions, remove_unreachable_areas_returning_most_distant,
 };
 use super::MapBuilder;
 use crate::{spawner, Map, Position, TileType, SHOW_MAPGEN_VISUALIZER};
+use common::*;
+use constraints::*;
+use image_loader::*;
 use rltk::RandomNumberGenerator;
+use solver::*;
 use specs::prelude::*;
 use std::collections::HashMap;
 
@@ -66,19 +72,42 @@ impl WaveformCollapseBuilder {
     fn build(&mut self) {
         let mut rng = RandomNumberGenerator::new();
 
-        self.map = load_rex_map(self.depth, &rltk::XpFile::from_resource("../resources/wfc-demo1.xp").unwrap());
+        const CHUNK_SIZE: i32 = 7;
+
+        self.map = load_rex_map(
+            self.depth,
+            &rltk::XpFile::from_resource("../resources/wfc-demo2.xp").unwrap(),
+        );
         self.take_snapshot();
 
+        let patterns = build_patterns(&self.map, CHUNK_SIZE, true, true);
+        let constraints = patterns_to_constraints(patterns, CHUNK_SIZE);
+        self.render_tile_gallery(&constraints, CHUNK_SIZE);
+
+        self.map = Map::new(self.depth);
+        loop {
+            let mut solver = Solver::new(constraints.clone(), CHUNK_SIZE, &self.map);
+            while !solver.iteration(&mut self.map, &mut rng) {
+                self.take_snapshot();
+            }
+            self.take_snapshot();
+            if solver.possible {
+                break;
+            } // If it has hit an impossible condition, try again
+        }
+
         // 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);
-        }
+        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
@@ -92,4 +121,34 @@ impl WaveformCollapseBuilder {
         // Now we build a noise map for use in spawning entities later
         self.noise_areas = generate_voronoi_spawn_regions(&self.map, &mut rng);
     }
+
+    fn render_tile_gallery(&mut self, constraints: &Vec<MapChunk>, chunk_size: i32) {
+        self.map = Map::new(0);
+        let mut counter = 0;
+        let mut x = 1;
+        let mut y = 1;
+
+        while counter < constraints.len() {
+            render_pattern_to_map(&mut self.map, &constraints[counter], chunk_size, x, y);
+
+            x += chunk_size + 1;
+            if x + chunk_size > self.map.width {
+                // Move to the next row
+                x = 1;
+                y += chunk_size + 1;
+
+                if y + chunk_size > self.map.height {
+                    // Move to the next page
+                    self.take_snapshot();
+                    self.map = Map::new(0);
+
+                    x = 1;
+                    y = 1;
+                }
+            }
+
+            counter += 1;
+        }
+        self.take_snapshot();
+    }
 }

src/map_builders/waveform_collapse/solver.rs

@@ -0,0 +1,225 @@
+use super::common::MapChunk;
+use crate::Map;
+use std::collections::HashSet;
+
+pub struct Solver {
+    constraints: Vec<MapChunk>,
+    chunk_size: i32,
+    chunks: Vec<Option<usize>>,
+    chunks_x: usize,
+    chunks_y: usize,
+    remaining: Vec<(usize, i32)>, // (index, # of neighbors)
+    pub possible: bool,
+}
+
+impl Solver {
+    pub fn new(constraints: Vec<MapChunk>, chunk_size: i32, map: &Map) -> Solver {
+        let chunks_x = (map.width / chunk_size) as usize;
+        let chunks_y = (map.height / chunk_size) as usize;
+        let mut remaining: Vec<(usize, i32)> = Vec::new();
+        for i in 0..(chunks_x * chunks_y) {
+            remaining.push((i, 0));
+        }
+
+        Solver {
+            constraints,
+            chunk_size,
+            chunks: vec![None; chunks_x * chunks_y],
+            chunks_x,
+            chunks_y,
+            remaining,
+            possible: true,
+        }
+    }
+
+    fn chunk_idx(&self, x: usize, y: usize) -> usize {
+        ((y * self.chunks_x) + x) as usize
+    }
+
+    fn count_neighbors(&self, chunk_x: usize, chunk_y: usize) -> i32 {
+        let mut neighbors = 0;
+
+        if chunk_x > 0 {
+            let left_idx = self.chunk_idx(chunk_x - 1, chunk_y);
+            if let Some(_) = self.chunks[left_idx] {
+                neighbors += 1;
+            }
+        }
+
+        if chunk_x < self.chunks_x - 1 {
+            let right_idx = self.chunk_idx(chunk_x + 1, chunk_y);
+            if let Some(_) = self.chunks[right_idx] {
+                neighbors += 1;
+            }
+        }
+
+        if chunk_y > 0 {
+            let up_idx = self.chunk_idx(chunk_x, chunk_y - 1);
+            if let Some(_) = self.chunks[up_idx] {
+                neighbors += 1;
+            }
+        }
+
+        if chunk_y < self.chunks_y - 1 {
+            let down_idx = self.chunk_idx(chunk_x, chunk_y + 1);
+            if let Some(_) = self.chunks[down_idx] {
+                neighbors += 1;
+            }
+        }
+
+        neighbors
+    }
+
+    pub fn iteration(&mut self, map: &mut Map, rng: &mut rltk::RandomNumberGenerator) -> bool {
+        if self.remaining.is_empty() {
+            return true;
+        }
+
+        // Populate the neighbor count of the remaining list
+        let mut remain_copy = self.remaining.clone();
+        let mut neighbors_exist = false;
+        for r in remain_copy.iter_mut() {
+            let idx = r.0;
+            let chunk_x = idx % self.chunks_x;
+            let chunk_y = idx / self.chunks_x;
+            let neighbor_count = self.count_neighbors(chunk_x, chunk_y);
+            if neighbor_count > 0 {
+                neighbors_exist = true;
+            }
+
+            *r = (r.0, neighbor_count);
+        }
+        remain_copy.sort_by(|a, b| b.1.cmp(&a.1));
+        self.remaining = remain_copy;
+
+        // Pick a random chunk we haven't dealt with yet and get its index, remove from remaining list
+        let remaining_index = if !neighbors_exist {
+            (rng.roll_dice(1, self.remaining.len() as i32) - 1) as usize
+        } else {
+            0_usize
+        };
+        let chunk_index = self.remaining[remaining_index].0;
+        self.remaining.remove(remaining_index);
+
+        let chunk_x = chunk_index % self.chunks_x;
+        let chunk_y = chunk_index / self.chunks_x;
+
+        let mut neighbors = 0;
+        let mut options: Vec<Vec<usize>> = Vec::new();
+
+        if chunk_x > 0 {
+            let left_idx = self.chunk_idx(chunk_x - 1, chunk_y);
+            match self.chunks[left_idx] {
+                None => {}
+                Some(nt) => {
+                    neighbors += 1;
+                    options.push(self.constraints[nt].compatible_with[3].clone());
+                }
+            }
+        }
+
+        if chunk_x < self.chunks_x - 1 {
+            let right_idx = self.chunk_idx(chunk_x + 1, chunk_y);
+            match self.chunks[right_idx] {
+                None => {}
+                Some(nt) => {
+                    neighbors += 1;
+                    options.push(self.constraints[nt].compatible_with[2].clone());
+                }
+            }
+        }
+
+        if chunk_y > 0 {
+            let up_idx = self.chunk_idx(chunk_x, chunk_y - 1);
+            match self.chunks[up_idx] {
+                None => {}
+                Some(nt) => {
+                    neighbors += 1;
+                    options.push(self.constraints[nt].compatible_with[1].clone());
+                }
+            }
+        }
+
+        if chunk_y < self.chunks_y - 1 {
+            let down_idx = self.chunk_idx(chunk_x, chunk_y + 1);
+            match self.chunks[down_idx] {
+                None => {}
+                Some(nt) => {
+                    neighbors += 1;
+                    options.push(self.constraints[nt].compatible_with[0].clone());
+                }
+            }
+        }
+
+        if neighbors == 0 {
+            // There is nothing nearby, so we can have anything!
+            let new_chunk_idx = (rng.roll_dice(1, self.constraints.len() as i32) - 1) as usize;
+            self.chunks[chunk_index] = Some(new_chunk_idx);
+            let left_x = chunk_x as i32 * self.chunk_size;
+            let right_x = (chunk_x + 1) as i32 * self.chunk_size;
+            let top_y = chunk_y as i32 * self.chunk_size;
+            let bottom_y = (chunk_y + 1) as i32 * self.chunk_size;
+
+            let mut i = 0_usize;
+            for y in top_y..bottom_y {
+                for x in left_x..right_x {
+                    let mapidx = map.xy_idx(x, y);
+                    let tile = self.constraints[new_chunk_idx].pattern[i];
+                    map.tiles[mapidx] = tile;
+                    i += 1;
+                }
+            }
+        } else {
+            // There are neighbors, so we try to be compatible with them
+            let mut options_to_check: HashSet<usize> = HashSet::new();
+            for o in options.iter() {
+                for i in o.iter() {
+                    options_to_check.insert(*i);
+                }
+            }
+
+            let mut possible_options: Vec<usize> = Vec::new();
+            for new_chunk_idx in options_to_check.iter() {
+                let mut possible = true;
+                for o in options.iter() {
+                    if !o.contains(new_chunk_idx) {
+                        possible = false;
+                    }
+                }
+                if possible {
+                    possible_options.push(*new_chunk_idx);
+                }
+            }
+
+            if possible_options.is_empty() {
+                rltk::console::log("Oh no! It's not possible!");
+                self.possible = false;
+
+                return true;
+            }
+
+            let new_chunk_idx = if possible_options.len() == 1 {
+                0
+            } else {
+                rng.roll_dice(1, possible_options.len() as i32) - 1
+            };
+            self.chunks[chunk_index] = Some(new_chunk_idx as usize);
+            let left_x = chunk_x as i32 * self.chunk_size;
+            let right_x = (chunk_x + 1) as i32 * self.chunk_size;
+            let top_y = chunk_y as i32 * self.chunk_size;
+            let bottom_y = (chunk_y + 1) as i32 * self.chunk_size;
+
+            let mut i = 0_usize;
+            for y in top_y..bottom_y {
+                for x in left_x..right_x {
+                    let mapidx = map.xy_idx(x, y);
+                    let tile = self.constraints[new_chunk_idx as usize].pattern[i];
+                    map.tiles[mapidx] = tile;
+                    i += 1;
+                }
+            }
+        }
+
+        false
+    }
+}