Stole @tocchan's ivec2 class

With his blessing. Ran Rider's formatter on it and tweaked a few things, but otherwise it's all his.

src/Util/Vec2.cs

@@ -0,0 +1,162 @@
+namespace aoc2022.Util;
+
+public struct ivec2 : IEquatable<ivec2>, IComparable<ivec2>, IComparable
+{
+    public int x = 0;
+    public int y = 0;
+
+    public static readonly ivec2 ZERO = new ivec2(0, 0);
+    public static readonly ivec2 ONE = new ivec2(1, 1);
+
+    public static readonly ivec2 LEFT = new ivec2(-1, 0);
+    public static readonly ivec2 RIGHT = new ivec2(1, 0);
+    public static readonly ivec2 UP = new ivec2(0, -1);
+    public static readonly ivec2 DOWN = new ivec2(0, 1);
+    public static readonly ivec2[] FOURWAY = {RIGHT, LEFT, UP, DOWN};
+    public static readonly ivec2[] EIGHTWAY = {UP, UP + RIGHT, RIGHT, RIGHT + DOWN, DOWN, DOWN + LEFT, LEFT, LEFT + UP};
+
+    public ivec2(int xv, int yv)
+    {
+        x = xv;
+        y = yv;
+    }
+
+    public bool IsZero() => x == 0 && y == 0;
+    public int Sum => x + y;
+    public int Product => x * y;
+    public int MaxElement => System.Math.Max(x, y);
+
+    public ivec2 GetRotatedLeft() => new ivec2(y, -x);
+    public void RotateLeft() => this = GetRotatedLeft();
+
+    public ivec2 GetRotatedRight() => new ivec2(-y, x);
+    public void RotateRight() => this = GetRotatedRight();
+
+    public int Dot(ivec2 v) => (x * v.x) + (y * v.y);
+    public int LengthSquared => (x * x) + (y * y);
+    public float Length => MathF.Sqrt(LengthSquared);
+
+    public int ManhattanDistance => Abs(this).Sum;
+    public int ManhattanDistanceTo(ivec2 other) => (this - other).ManhattanDistance;
+
+    public ivec2 GetBestDirectionTo(ivec2 p)
+    {
+        ivec2 diff = p - this;
+        if (diff.IsZero())
+        {
+            return ZERO;
+        }
+
+        ivec2 dir = diff / Abs(diff).MaxElement;
+        return Sign(dir);
+    }
+
+    // get a point in the 8 cells around me closest to p
+    public ivec2 GetNearestNeighbor(ivec2 p)
+    {
+        ivec2 dir = GetBestDirectionTo(p);
+        return this + dir;
+    }
+
+    public int this[int i]
+    {
+        get => (i == 0) ? x : y;
+        set
+        {
+            if (i == 0)
+            {
+                x = value;
+            }
+            else
+            {
+                y = value;
+            }
+        }
+    }
+
+    public static ivec2 operator +(ivec2 v) => v;
+    public static ivec2 operator -(ivec2 v) => new ivec2(-v.x, -v.y);
+    public static ivec2 operator +(ivec2 a, ivec2 b) => new ivec2(a.x + b.x, a.y + b.y);
+    public static ivec2 operator -(ivec2 a, ivec2 b) => new ivec2(a.x - b.x, a.y - b.y);
+    public static ivec2 operator *(ivec2 a, ivec2 b) => new ivec2(a.x * b.x, a.y * b.y);
+    public static ivec2 operator *(int a, ivec2 v) => new ivec2(a * v.x, a * v.y);
+    public static ivec2 operator *(ivec2 v, int a) => new ivec2(a * v.x, a * v.y);
+    public static ivec2 operator /(ivec2 v, int a) => new ivec2(v.x / a, v.y / a);
+    public static bool operator ==(ivec2 a, ivec2 b) => (a.x == b.x) && (a.y == b.y);
+    public static bool operator !=(ivec2 a, ivec2 b) => (a.x != b.x) || (a.y != b.y);
+    public static bool operator <(ivec2 a, ivec2 b) => (a.x < b.x) && (a.y < b.y);
+    public static bool operator <=(ivec2 a, ivec2 b) => (a.x <= b.x) && (a.y <= b.y);
+    public static bool operator >(ivec2 a, ivec2 b) => (a.x > b.x) && (a.y > b.y);
+    public static bool operator >=(ivec2 a, ivec2 b) => (a.x >= b.x) && (a.y >= b.y);
+
+    public bool Equals(ivec2 other)
+    {
+        return x == other.x && y == other.y;
+    }
+
+    public override bool Equals(object? obj)
+    {
+        return obj is ivec2 other && Equals(other);
+    }
+
+    public int CompareTo(ivec2 other)
+    {
+        if (this < other)
+        {
+            return -1;
+        }
+
+        if (this > other)
+        {
+            return 1;
+        }
+
+        return 0;
+    }
+
+    public int CompareTo(object? obj)
+    {
+        if (ReferenceEquals(null, obj)) return 1;
+        return obj is ivec2 other ? CompareTo(other) : throw new ArgumentException($"Object must be of type {nameof(ivec2)}");
+    }
+
+    public static ivec2 Sign(ivec2 v) => new ivec2(System.Math.Sign(v.x), System.Math.Sign(v.y));
+    public static ivec2 Min(ivec2 a, ivec2 b) => new ivec2(System.Math.Min(a.x, b.x), System.Math.Min(a.y, b.y));
+    public static ivec2 Max(ivec2 a, ivec2 b) => new ivec2(System.Math.Max(a.x, b.x), System.Math.Max(a.y, b.y));
+
+    public static ivec2 Clamp(ivec2 v, ivec2 lh, ivec2 rh) => Min(rh, Max(lh, v));
+
+    public static ivec2 Abs(ivec2 v) => new ivec2(System.Math.Abs(v.x), System.Math.Abs(v.y));
+
+    public static ivec2 Mod(ivec2 val, int den)
+    {
+        int x = val.x % den;
+        int y = val.y % den;
+
+        if (x < 0)
+        {
+            x += den;
+        }
+
+        if (y < 0)
+        {
+            y += den;
+        }
+
+        return new ivec2(x, y);
+    }
+
+    public static int Dot(ivec2 a, ivec2 b) => (a.x * b.x) + (a.y * b.y);
+
+    public static ivec2 Parse(string s)
+    {
+        string[] parts = s.Split(',', 2);
+        int x = int.Parse(parts[0]);
+        int y = int.Parse(parts[1]);
+        return new ivec2(x, y);
+    }
+
+    public override int GetHashCode() => HashCode.Combine(x, y);
+
+    public override string ToString() => $"{x},{y}";
+}