some extra utils

1 files changed, 22 insertions, 0 deletions

diff --git a/utils/point2d.ts b/utils/point2d.ts
index 3d07569..45bee2e 100644
--- a/utils/point2d.ts
+++ b/utils/point2d.ts
@@ -7,3 +7,25 @@ export const l2Norm = (p1: Vec2, p2: Vec2) =>
   Math.sqrt(Math.pow(p2.x - p1.x, 2) + Math.pow(p2.y - p1.y, 2));
 
 export const isDiagAdj = (p1: Vec2, p2: Vec2) => l2Norm(p1, p2) <= Math.sqrt(2);
+
+export const neighbors = (p1: Vec2, max: Vec2) => {
+  const ns: Vec2[] = [];
+  const { x, y } = p1;
+  for (let dy = -1; dy <= 1; dy++) {
+    for (let dx = -1; dx <= 1; dx++) {
+      const [newX, newY] = [dx + x, dy + y];
+      if (
+        !(dy === dx && dy === 0) &&
+        newX >= 0 &&
+        newX < max.x &&
+        newY < max.y &&
+        newY >= 0
+      ) {
+        ns.push({ x: newX, y: newY });
+      }
+    }
+  }
+  return ns;
+};
+
+export const;