optimize away a dictionary lookup in SpatialHash

Bonk/BroadPhase/SpatialHash.cs

@@ -12,7 +12,7 @@ namespace MoonTools.Core.Bonk
     {
         private readonly int cellSize;
 
-        private readonly Dictionary<int, Dictionary<int, HashSet<T>>> hashDictionary = new Dictionary<int, Dictionary<int, HashSet<T>>>();
+        private readonly Dictionary<long, HashSet<T>> hashDictionary = new Dictionary<long, HashSet<T>>();
         private readonly Dictionary<T, (IShape2D, Transform2D)> IDLookup = new Dictionary<T, (IShape2D, Transform2D)>();
 
         public SpatialHash(int cellSize)
@@ -41,17 +41,13 @@ namespace MoonTools.Core.Bonk
             {
                 for (int j = minHash.Item2; j <= maxHash.Item2; j++)
                 {
-                    if (!hashDictionary.ContainsKey(i))
+                    var key = LongHelper.MakeLong(i, j);
+                    if (!hashDictionary.ContainsKey(key))
                     {
-                        hashDictionary.Add(i, new Dictionary<int, HashSet<T>>());
+                        hashDictionary.Add(key, new HashSet<T>());
                     }
 
-                    if (!hashDictionary[i].ContainsKey(j))
+                    hashDictionary[key].Add(id);
-                    {
-                        hashDictionary[i].Add(j, new HashSet<T>());
-                    }
-
-                    hashDictionary[i][j].Add(id);
                     IDLookup[id] = (shape, transform2D);
                 }
             }
@@ -70,9 +66,10 @@ namespace MoonTools.Core.Bonk
             {
                 for (int j = minHash.Item2; j <= maxHash.Item2; j++)
                 {
-                    if (hashDictionary.ContainsKey(i) && hashDictionary[i].ContainsKey(j))
+                    var key = LongHelper.MakeLong(i, j);
+                    if (hashDictionary.ContainsKey(key))
                     {
-                        foreach (var t in hashDictionary[i][j])
+                        foreach (var t in hashDictionary[key])
                         {
                             var (otherShape, otherTransform) = IDLookup[t];
                             if (!id.Equals(t)) { yield return (t, otherShape, otherTransform); }
@@ -87,12 +84,9 @@ namespace MoonTools.Core.Bonk
         /// </summary>
         public void Clear()
         {
-            foreach (var innerDict in hashDictionary.Values)
+            foreach (var hash in hashDictionary.Values)
             {
-                foreach (var set in innerDict.Values)
+                hash.Clear();
-                {
-                    set.Clear();
-                }
             }
 
             IDLookup.Clear();

Bonk/LongHelper.cs

@@ -0,0 +1,10 @@
+namespace MoonTools.Core.Bonk
+{
+    public static class LongHelper
+    {
+        public static long MakeLong(int left, int right)
+        {
+            return ((long)left << 32) | ((uint)right);
+        }
+    }
+}

Test/SpatialHashTest.cs

@@ -13,28 +13,28 @@ namespace Tests
         {
             var spatialHash = new SpatialHash<int>(16);
 
-            var rectA = new MoonTools.Core.Bonk.Rectangle(-2, -2, 2, 2);
+            var rectA = new Rectangle(-2, -2, 2, 2);
             var rectATransform = new Transform2D(new Vector2(-8, -8));
 
-            var rectB = new MoonTools.Core.Bonk.Rectangle(-2, -2, 2, 2);
+            var rectB = new Rectangle(-2, -2, 2, 2);
             var rectBTransform = new Transform2D(new Vector2(8, 8));
 
-            var rectC = new MoonTools.Core.Bonk.Rectangle(-2, -2, 2, 2);
+            var rectC = new Rectangle(-2, -2, 2, 2);
             var rectCTransform = new Transform2D(new Vector2(24, -4));
 
-            var rectD = new MoonTools.Core.Bonk.Rectangle(-2, -2, 2, 2);
+            var rectD = new Rectangle(-2, -2, 2, 2);
             var rectDTransform = new Transform2D(new Vector2(24, 24));
 
-            var circleA = new MoonTools.Core.Bonk.Circle(2);
+            var circleA = new Circle(2);
             var circleATransform = new Transform2D(new Vector2(24, -8));
 
-            var circleB = new MoonTools.Core.Bonk.Circle(8);
+            var circleB = new Circle(8);
             var circleBTransform = new Transform2D(new Vector2(16, 16));
 
-            var line = new MoonTools.Core.Bonk.Line(new Position2D(20, -4), new Position2D(22, -12));
+            var line = new Line(new Position2D(20, -4), new Position2D(22, -12));
             var lineTransform = new Transform2D(new Vector2(0, 0));
 
-            var point = new MoonTools.Core.Bonk.Point(8, 8);
+            var point = new Point(8, 8);
             var pointTransform = Transform2D.DefaultTransform;
 
             spatialHash.Insert(0, rectA, rectATransform);
@@ -63,13 +63,13 @@ namespace Tests
         {
             var spatialHash = new SpatialHash<int>(16);
 
-            var rectA = new MoonTools.Core.Bonk.Rectangle(-2, -2, 2, 2);
+            var rectA = new Rectangle(-2, -2, 2, 2);
             var rectATransform = new Transform2D(new Vector2(-8, -8));
 
-            var rectB = new MoonTools.Core.Bonk.Rectangle(-2, -2, 2, 2);
+            var rectB = new Rectangle(-2, -2, 2, 2);
             var rectBTransform = new Transform2D(new Vector2(-8, -8));
 
-            var rectC = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var rectC = new Rectangle(-1, -1, 1, 1);
             var rectCTransform = new Transform2D(new Vector2(-8, -8));
 
             spatialHash.Insert(0, rectA, rectATransform);
@@ -84,10 +84,10 @@ namespace Tests
         {
             var spatialHash = new SpatialHash<int>(16);
 
-            var rectA = new MoonTools.Core.Bonk.Rectangle(-2, -2, 2, 2);
+            var rectA = new Rectangle(-2, -2, 2, 2);
             var rectATransform = new Transform2D(new Vector2(-8, -8));
 
-            var rectB = new MoonTools.Core.Bonk.Rectangle(-2, -2, 2, 2);
+            var rectB = new Rectangle(-2, -2, 2, 2);
             var rectBTransform = new Transform2D(new Vector2(8, 8));
 
             spatialHash.Insert(0, rectA, rectATransform);