From 2e4fba61e481612df78f8734e8de2390ce819104 Mon Sep 17 00:00:00 2001
From: klangner <klangner@gmail.com>
Date: Thu, 19 Nov 2020 20:53:34 +0100
Subject: [PATCH] implemented Voronoi Hive. Fixed: 30

---
 README.md             |  2 +-
 src/filter/mod.rs     |  2 +
 src/filter/voronoi.rs | 98 +++++++++++++++++++++++++++++++++++++++++++
 src/map.rs            |  6 ++-
 4 files changed, 106 insertions(+), 2 deletions(-)
 create mode 100644 src/filter/voronoi.rs

diff --git a/README.md b/README.md
index 3b8618c..c5d9ed5 100644
--- a/README.md
+++ b/README.md
@@ -26,7 +26,7 @@ This library consists of different map filters which can be combined to create c
   * [ ] Prefabs
   * [x] Room corridors nearest
   * [x] Simple rooms
-  * [ ] Voronoi hive
+  * [x] Voronoi hive
   * [ ] Wave Function Collapse
 
 
diff --git a/src/filter/mod.rs b/src/filter/mod.rs
index 0c191a6..5df3895 100644
--- a/src/filter/mod.rs
+++ b/src/filter/mod.rs
@@ -12,6 +12,7 @@ pub mod noise_generator;
 pub mod simple_rooms;
 pub mod rooms_corridors_nearest;
 pub mod starting_point;
+pub mod voronoi;
 
 pub use bsp_interior::BspInterior;
 pub use bsp_rooms::BspRooms;
@@ -24,4 +25,5 @@ pub use noise_generator::NoiseGenerator;
 pub use simple_rooms::SimpleRooms;
 pub use rooms_corridors_nearest::NearestCorridors;
 pub use starting_point::{AreaStartingPosition, XStart, YStart};
+pub use voronoi::VoronoiHive;
 
diff --git a/src/filter/voronoi.rs b/src/filter/voronoi.rs
new file mode 100644
index 0000000..b7777cf
--- /dev/null
+++ b/src/filter/voronoi.rs
@@ -0,0 +1,98 @@
+//! Example generator usage:
+//! ```
+//! use rand::prelude::*;
+//! use mapgen::{Map, MapFilter};
+//! use mapgen::filter::VoronoiHive;
+//! 
+//! let mut rng = StdRng::seed_from_u64(100);
+//! let gen = VoronoiHive::new();
+//! let map = gen.modify_map(&mut rng, &Map::new(80, 50));
+//! 
+//! assert_eq!(map.width, 80);
+//! assert_eq!(map.height, 50);
+//! ```
+//! 
+
+use rand::prelude::*;
+use crate::MapFilter;
+use crate::{
+    map::{Map, TileType},
+    random::Rng,
+    geometry::Point,
+};
+
+
+pub struct VoronoiHive {
+    n_seeds: usize,
+}
+
+
+impl MapFilter for VoronoiHive {
+    fn modify_map(&self, rng: &mut StdRng, map: &Map)  -> Map {
+        self.build(rng, map)
+    }
+}
+
+impl VoronoiHive {
+    pub fn new() -> Box<VoronoiHive> {
+        Box::new(VoronoiHive{
+            n_seeds: 64,
+        })
+    }
+
+    fn build(&self, rng: &mut StdRng, map: &Map) -> Map {
+        let mut new_map = map.clone();
+        let seeds = self.generate_seeds(rng, map.width, map.height);
+
+        let mut voronoi_distance = vec![(0, 0.0f32) ; self.n_seeds];
+        let mut voronoi_membership : Vec<i32> = vec![0 ; map.width as usize * map.height as usize];
+        for (i, vid) in voronoi_membership.iter_mut().enumerate() {
+            let x = i % map.width;
+            let y = i / map.width;
+
+            for (seed, pos) in seeds.iter().enumerate() {
+                let distance = pos.distance_to(&Point::new(x, y));
+                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..new_map.height-1 {
+            for x in 1..new_map.width-1 {
+                let mut neighbors = 0;
+                let my_idx = new_map.xy_idx(x, y);
+                let my_seed = voronoi_membership[my_idx];
+                if voronoi_membership[new_map.xy_idx(x-1, y)] != my_seed { neighbors += 1; }
+                if voronoi_membership[new_map.xy_idx(x+1, y)] != my_seed { neighbors += 1; }
+                if voronoi_membership[new_map.xy_idx(x, y-1)] != my_seed { neighbors += 1; }
+                if voronoi_membership[new_map.xy_idx(x, y+1)] != my_seed { neighbors += 1; }
+
+                if neighbors < 2 {
+                    new_map.set_tile(x, y, TileType::Floor);
+                }
+            }
+        }
+
+        new_map
+    }    
+    
+    /// Generate random seeds
+    fn generate_seeds(&self, rng: &mut StdRng, width: usize, height: usize) -> Vec<Point> {
+        let mut seeds: Vec<Point> = Vec::new();
+
+        while seeds.len() < self.n_seeds {
+            let vx = rng.roll_dice(1, width-1);
+            let vy = rng.roll_dice(1, height-1);
+            let candidate = Point::new(vx, vy);
+            if !seeds.contains(&candidate) {
+                seeds.push(candidate);
+            }
+        }
+
+        seeds
+    }
+
+}
\ No newline at end of file
diff --git a/src/map.rs b/src/map.rs
index 149dad3..085057b 100644
--- a/src/map.rs
+++ b/src/map.rs
@@ -106,10 +106,14 @@ impl Map {
     /// Modify tile at the given location
     pub fn set_tile(&mut self, x: usize, y: usize, tile: TileType) {
         if x < self.width && y < self.height {
-            let idx = (y as usize) * self.width + (x as usize);
+            let idx = self.xy_idx(x as usize, y as usize);
             self.tiles[idx] = tile;
         }
     }
+
+    pub fn xy_idx(&self, x: usize, y: usize) -> usize {
+        y * self.width + x        
+    }
     
     /// Create room on the map at given location
     /// Room is created by setting all tiles in the room to the Floor