simplify borders management

A region's boundary is simply composed of the set of the cells that are farthest away from the pivot, but that are always inside of the region.

Author: danieledapo

src/main.rs

@@ -15,16 +15,14 @@ fn main() {
  let cm = ColorMap::color(&m).unwrap();
  let regions = &m.regions;
 
- let c1 = " ".on_red().to_string();
- let c2 = " ".on_blue().to_string();
- let c3 = " ".on_green().to_string();
- let c4 = " ".on_yellow().to_string();
+ let c1 = " ".on_red().dimmed().to_string();
+ let c2 = " ".on_blue().dimmed().to_string();
+ let c3 = " ".on_green().dimmed().to_string();
+ let c4 = " ".on_yellow().dimmed().to_string();
  let p1 = "X".on_red().to_string();
  let p2 = "X".on_blue().to_string();
  let p3 = "X".on_green().to_string();
  let p4 = "X".on_yellow().to_string();
- let pb = "X".on_black().to_string();
- let b = " ".on_black().to_string();
 
  let mut dbg_display = vec![vec![" "; usize::from(dim.0)]; usize::from(dim.1)];
  for (y, row) in m.raster.iter().enumerate() {
@@ -38,20 +36,26 @@ fn main() {
  }
  }
 
- for r in regions.iter() {
- for (x, y) in &r.boundary {
- dbg_display[y.floor() as usize][x.floor() as usize] = &b;
- }
- }
+ // print boundaries
+ // let b1 = "*".on_red().to_string();
+ // let b2 = "*".on_blue().to_string();
+ // let b3 = "*".on_green().to_string();
+ // let b4 = "*".on_yellow().to_string();
+ // for (rid, r) in regions.iter().enumerate() {
+ // for (x, y) in &r.boundary {
+ // dbg_display[usize::from(*y)][usize::from(*x)] = match cm.color_of_region(rid) {
+ // Color::C1 => &b1,
+ // Color::C2 => &b2,
+ // Color::C3 => &b3,
+ // Color::C4 => &b4,
+ // };
+ // }
+ // }
+
  for (rid, r) in regions.iter().enumerate() {
  let x = usize::from(r.pivot.0);
  let y = usize::from(r.pivot.1);
 
- if dbg_display[y][x] == b {
- dbg_display[y][x] = &pb;
- continue;
- }
-
  dbg_display[y][x] = match cm.color_of_region(rid) {
  Color::C1 => &p1,
  Color::C2 => &p2,

src/map.rs

@@ -2,7 +2,7 @@ use std::collections::HashSet;
 
 use rand::prelude::*;
 
-pub type Point = (f32, f32);
+pub type Point = (u16, u16);
 pub type RegionId = usize;
 
 #[derive(Debug)]
@@ -13,22 +13,27 @@ pub struct Map {
 
 #[derive(Debug)]
 pub struct Region {
- pub pivot: (u16, u16),
+ /// seed point of the region
+ pub pivot: Point,
+
+ /// the farthest points of the region that are still part of the region
  pub boundary: Vec<Point>,
+
+ /// all the regions that share a border this region
  pub neighbors: HashSet<RegionId>,
 }
 
 impl Map {
- pub fn voronoi_like(rng: &mut impl Rng, (w, h): (u8, u8), npivots: usize) -> Self {
- assert!(w > 2);
- assert!(h > 2);
+ pub fn voronoi_like(rng: &mut impl Rng, (w, h): (u16, u16), npivots: usize) -> Self {
+ assert!(w > 0);
+ assert!(h > 0);
 
  // TODO: find a better way to generate distinct pivot points
  let mut regions = (0..npivots)
  .map(|_| Region {
  pivot: {
- let x = rng.gen_range(1, u16::from(w) - 1);
- let y = rng.gen_range(1, u16::from(h) - 1);
+ let x = rng.gen_range(0, w);
+ let y = rng.gen_range(0, h);
  (x, y)
  },
  boundary: vec![],
@@ -48,9 +53,6 @@ impl Map {
  canvas[y][x] = region_id;
  }
 
- // TODO: it seems boundaries are a bit too thick in some cases, try to stick to boundaries
- // of 1pix so that it's easier to generate non piexelated boundaries in case of svg output
- // or similar
  loop {
  let mut changed = false;
 
@@ -62,16 +64,7 @@ impl Map {
  let ox = i32::from(p.0);
  let oy = i32::from(p.1);
 
- [
- // (ox - 1, oy - 1),
- // (ox - 1, oy + 1),
- // (ox + 1, oy - 1),
- // (ox + 1, oy + 1),
- (ox - 1, oy),
- (ox, oy - 1),
- (ox, oy + 1),
- (ox + 1, oy),
- ]
+ [(ox - 1, oy), (ox, oy - 1), (ox, oy + 1), (ox + 1, oy)]
  };
 
  for &(x, y) in &neighbors {
@@ -81,10 +74,9 @@ impl Map {
  let x = x as u16;
  let y = y as u16;
 
- let on_boundary =
- x == 0 || x == u16::from(w) - 1 || y == 0 || y == u16::from(h) - 1;
+ let on_boundary = x == 0 || x == w - 1 || y == 0 || y == h - 1;
 
- let mut closest_rid = canvas[y as usize][x as usize];
+ let mut closest_rid = canvas[usize::from(y)][usize::from(x)];
  if closest_rid >= regions.len() {
  canvas[usize::from(y)][usize::from(x)] = region_id;
  closest_rid = region_id;
@@ -94,14 +86,9 @@ impl Map {
  if closest_rid != region_id {
  regions[region_id].neighbors.insert(closest_rid);
  regions[closest_rid].neighbors.insert(region_id);
- regions[region_id].boundary.push((
- (f32::from(x) + f32::from(p.0)) / 2.0,
- (f32::from(y) + f32::from(p.1)) / 2.0,
- ));
+ regions[region_id].boundary.push(*p);
  } else if on_boundary {
- regions[region_id]
- .boundary
- .push((f32::from(x), f32::from(y)));
+ regions[region_id].boundary.push((x, y));
  }
  }
  }