add Update and Remove to SpatialHash2D

src/Collision/AABB2D.cs

@@ -142,7 +142,7 @@ namespace MoonWorks.Collision
 
 		public static bool TestOverlap(AABB2D a, AABB2D b)
 		{
-			return a.Left <= b.Right && a.Right >= b.Left && a.Top <= b.Bottom && a.Bottom >= b.Top;
+			return a.Left < b.Right && a.Right > b.Left && a.Top < b.Bottom && a.Bottom > b.Top;
 		}
 
 		public override bool Equals(object obj)

src/Collision/SpatialHash2D.cs

@@ -44,11 +44,8 @@ namespace MoonWorks.Collision
 			var minHash = Hash(box.Min);
 			var maxHash = Hash(box.Max);
 
-			for (var i = minHash.Item1; i <= maxHash.Item1; i++)
+			foreach (var key in Keys(minHash.Item1, minHash.Item2, maxHash.Item1, maxHash.Item2))
 			{
-				for (var j = minHash.Item2; j <= maxHash.Item2; j++)
-				{
-					var key = MakeLong(i, j);
 				if (!hashDictionary.ContainsKey(key))
 				{
 					hashDictionary.Add(key, new HashSet<T>());
@@ -57,7 +54,6 @@ namespace MoonWorks.Collision
 				hashDictionary[key].Add(id);
 				IDLookup[id] = (shape, transform2D, collisionGroups);
 			}
-			}
 
 			MinX = System.Math.Min(MinX, minHash.Item1);
 			MinY = System.Math.Min(MinY, minHash.Item2);
@@ -81,11 +77,8 @@ namespace MoonWorks.Collision
 			if (minY < MinY) { minY = MinY; }
 			if (maxY > MaxY) { maxY = MaxY; }
 
-			for (var i = minX; i <= maxX; i++)
+			foreach (var key in Keys(minX, minY, maxX, maxY))
 			{
-				for (var j = minY; j <= maxY; j++)
-				{
-					var key = MakeLong(i, j);
 				if (hashDictionary.ContainsKey(key))
 				{
 					foreach (var t in hashDictionary[key])
@@ -102,7 +95,6 @@ namespace MoonWorks.Collision
 					}
 				}
 			}
-			}
 
 			FreeHashSet(returned);
 		}
@@ -125,11 +117,8 @@ namespace MoonWorks.Collision
 			if (minY < MinY) { minY = MinY; }
 			if (maxY > MaxY) { maxY = MaxY; }
 
-			for (var i = minX; i <= maxX; i++)
+			foreach (var key in Keys(minX, minY, maxX, maxY))
 			{
-				for (var j = minY; j <= maxY; j++)
-				{
-					var key = MakeLong(i, j);
 				if (hashDictionary.ContainsKey(key))
 				{
 					foreach (var t in hashDictionary[key])
@@ -145,17 +134,36 @@ namespace MoonWorks.Collision
 					}
 				}
 			}
-			}
 
 			FreeHashSet(returned);
 		}
 
+		public void Update(T id, ICollidable shape, Transform2D transform2D, uint collisionGroups = uint.MaxValue)
+		{
+			Remove(id);
+			Insert(id, shape, transform2D, collisionGroups);
+		}
+
 		/// <summary>
 		/// Removes a specific ID from the SpatialHash.
 		/// </summary>
 		public void Remove(T id)
 		{
+			var (shape, transform, collisionGroups) = IDLookup[id];
 
+			var box = shape.TransformedAABB(transform);
+			var minHash = Hash(box.Min);
+			var maxHash = Hash(box.Max);
+
+			foreach (var key in Keys(minHash.Item1, minHash.Item2, maxHash.Item1, maxHash.Item2))
+			{
+				if (hashDictionary.ContainsKey(key))
+				{
+					hashDictionary[key].Remove(id);
+				}
+			}
+
+			IDLookup.Remove(id);
 		}
 
 		/// <summary>
@@ -176,6 +184,17 @@ namespace MoonWorks.Collision
 			return ((long) left << 32) | ((uint) right);
 		}
 
+		private IEnumerable<long> Keys(int minX, int minY, int maxX, int maxY)
+		{
+			for (var i = minX; i <= maxX; i++)
+			{
+				for (var j = minY; j <= maxY; j++)
+				{
+					yield return MakeLong(i, j);
+				}
+			}
+		}
+
 		private HashSet<T> AcquireHashSet()
 		{
 			if (hashSetPool.Count == 0)