Switch to Vector2

Gameboard.ShogiUI.BoardState/Array2D.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Numerics;
 
 namespace Gameboard.ShogiUI.BoardState
 {
@@ -24,6 +25,11 @@ namespace Gameboard.ShogiUI.BoardState
       get => array[y * width + x];
       set => array[y * width + x] = value;
     }
+    public T this[float x, float y]
+    {
+      get => array[(int)y * width + (int)x];
+      set => array[(int)y * width + (int)x] = value;
+    }
 
     public void ForEach(ForEachDelegate callback)
     {
@@ -48,15 +54,14 @@ namespace Gameboard.ShogiUI.BoardState
       }
     }
 
-    // TODO: Figure out a better return type, or make this class specific to ShogiBoard.
-    public BoardVector IndexOf(Predicate<T> predicate)
+    public Vector2? IndexOf(Predicate<T> predicate)
     {
       for (var x = 0; x < width; x++)
         for (var y = 0; y < height; y++)
         {
           if (this[x, y] != null && predicate(this[x, y]))
           {
-            return new BoardVector(x, y);
+            return new Vector2(x, y);
           }
         }
       return null;