.

packages/demo/demo.rust.ts

@@ -9,8 +9,6 @@ import { grid } from "./sample";
 
 	const freeCells = api.iget_free_cell(g);
 
-	console.log(freeCells);
-
 	{
 		const { canvas, draw, highlightCell } = createCanvas(g);
 		document.body.appendChild(canvas);

packages/solver-r/Cargo.lock

@@ -33,6 +33,16 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "console_log"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be8aed40e4edbf4d3b4431ab260b63fdc40f5780a4766824329ea0f1eefe3c0f"
+dependencies = [
+ "log",
+ "web-sys",
+]
+
 [[package]]
 name = "js-sys"
 version = "0.3.77"
@@ -109,7 +119,9 @@ name = "snk-solver-rust"
 version = "1.0.0"
 dependencies = [
  "console_error_panic_hook",
+ "console_log",
  "js-sys",
+ "log",
  "wasm-bindgen",
  "wasm-bindgen-test",
 ]

packages/solver-r/Cargo.toml

@@ -13,6 +13,8 @@ default = ["console_error_panic_hook"]
 [dependencies]
 wasm-bindgen = "0.2.100"
 js-sys = "0.3.77"
+console_log = "1.0.0"
+log = "0.4"
 
 # The `console_error_panic_hook` crate provides better debugging of panics by
 # logging them with `console.error`. This is great for development, but requires

packages/solver-r/src/lib.rs

@@ -6,6 +6,9 @@ use js_sys;
 use solver::get_free_cell;
 use wasm_bindgen::prelude::*;
 
+use log::info;
+use log::Level;
+
 #[wasm_bindgen]
 extern "C" {
     fn alert(s: &str);

packages/solver-r/src/solver.rs

@@ -6,13 +6,21 @@ pub fn get_free_cell(grid: &Grid, walkable: Cell) -> HashSet<Point> {
     let mut free: HashSet<Point> = HashSet::new();
     let mut open_list: HashSet<Point> = HashSet::new();
 
-    for x in -1..((grid.width as i8) + 1) {
+    for x in 0..(grid.width as i8) {
         open_list.insert(Point { x, y: 0 });
         open_list.insert(Point {
             x,
             y: (grid.height as i8) - 1,
         });
     }
+    for y in 0..(grid.height as i8) {
+        open_list.insert(Point { x: 0, y });
+        open_list.insert(Point {
+            x: (grid.width as i8) - 1,
+            y,
+        });
+    }
+    open_list.retain(|p| grid.get_cell(&p) <= walkable);
 
     let directions = [
         Point { x: 1, y: 0 },
@@ -24,25 +32,9 @@ pub fn get_free_cell(grid: &Grid, walkable: Cell) -> HashSet<Point> {
     while let Some(p) = open_list.iter().next().cloned() {
         open_list.remove(&p);
 
-        let exit_count: u8 = directions.iter().fold(0, |sum, dir| {
+        let has_enough_free_exits = {
-            let neighbour = Point {
+            let mut exit_count = 0;
-                x: p.x + dir.x,
+            let mut visited: HashSet<Point> = HashSet::new();
-                y: p.y + dir.y,
-            };
-
-            if !grid.is_inside(&neighbour) {
-                sum + 2
-            } else if free.contains(&neighbour) {
-                sum + 1
-            } else {
-                sum
-            }
-        });
-
-        if exit_count >= 2 {
-            if grid.is_inside(&p) && grid.get_cell(&p) <= walkable {
-                free.insert(p);
-            }
 
             for dir in directions {
                 let neighbour = Point {
@@ -50,9 +42,56 @@ pub fn get_free_cell(grid: &Grid, walkable: Cell) -> HashSet<Point> {
                     y: p.y + dir.y,
                 };
 
-                if grid.is_inside(&neighbour)
+                if !visited.contains(&neighbour)
-                    && (grid.get_cell(&neighbour) <= walkable)
+                    && (free.contains(&neighbour) || !grid.is_inside(&neighbour))
-                    && !free.contains(&neighbour)
+                {
+                    visited.insert(neighbour);
+                    exit_count += 1;
+                }
+
+                if grid.is_inside(&neighbour) && grid.get_cell(&neighbour) <= walkable {
+                    for alt in [-1, 1] {
+                        let corner = {
+                            if neighbour.x != 0 {
+                                Point {
+                                    x: neighbour.x,
+                                    y: neighbour.y + alt,
+                                }
+                            } else {
+                                Point {
+                                    x: neighbour.x + alt,
+                                    y: neighbour.y,
+                                }
+                            }
+                        };
+
+                        if !visited.contains(&neighbour)
+                            && !visited.contains(&corner)
+                            && (free.contains(&corner) || !grid.is_inside(&corner))
+                        {
+                            visited.insert(neighbour);
+                            visited.insert(corner);
+                            exit_count += 1;
+                        }
+                    }
+                }
+            }
+
+            exit_count >= 2
+        };
+
+        if has_enough_free_exits {
+            free.insert(p);
+
+            for dir in directions {
+                let neighbour = Point {
+                    x: p.x + dir.x,
+                    y: p.y + dir.y,
+                };
+
+                if !free.contains(&neighbour)
+                    && grid.is_inside(&neighbour)
+                    && grid.get_cell(&neighbour) <= walkable
                 {
                     open_list.insert(neighbour);
                 }