new multishape pattern

Bonk/BroadPhase/SpatialHash.cs

@@ -14,7 +14,7 @@ namespace MoonTools.Core.Bonk
         private readonly int cellSize;
 
         private readonly Dictionary<long, HashSet<T>> hashDictionary = new Dictionary<long, HashSet<T>>();
-        private readonly Dictionary<T, (IShape2D, Transform2D)> IDLookup = new Dictionary<T, (IShape2D, Transform2D)>();
+        private readonly Dictionary<T, (IHasAABB2D, Transform2D)> IDLookup = new Dictionary<T, (IHasAABB2D, Transform2D)>();
 
         public SpatialHash(int cellSize)
         {
@@ -32,7 +32,7 @@ namespace MoonTools.Core.Bonk
         /// <param name="id">A unique ID for the shape-transform pair.</param>
         /// <param name="shape"></param>
         /// <param name="transform2D"></param>
-        public void Insert(T id, IShape2D shape, Transform2D transform2D)
+        public void Insert(T id, IHasAABB2D shape, Transform2D transform2D)
         {
             var box = shape.TransformedAABB(transform2D);
             var minHash = Hash(box.Min);
@@ -57,7 +57,7 @@ namespace MoonTools.Core.Bonk
         /// <summary>
         /// Retrieves all the potential collisions of a shape-transform pair. Excludes any shape-transforms with the given ID.
         /// </summary>
-        public IEnumerable<(T, IShape2D, Transform2D)> Retrieve(T id, IShape2D shape, Transform2D transform2D)
+        public IEnumerable<(T, IHasAABB2D, Transform2D)> Retrieve(T id, IHasAABB2D shape, Transform2D transform2D)
         {
             var box = shape.TransformedAABB(transform2D);
             var minHash = Hash(box.Min);

Bonk/IHasAABB2D.cs

@@ -0,0 +1,17 @@
+using System;
+using MoonTools.Core.Structs;
+
+namespace MoonTools.Core.Bonk
+{
+    public interface IHasAABB2D
+    {
+        AABB AABB { get; }
+
+        /// <summary>
+        /// Returns a bounding box based on the shape.
+        /// </summary>
+        /// <param name="transform">A Transform for transforming the shape vertices.</param>
+        /// <returns>Returns a bounding box based on the shape.</returns>
+        AABB TransformedAABB(Transform2D transform);
+    }
+}

Bonk/IMultiShape2D.cs

@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+using MoonTools.Core.Structs;
+
+namespace MoonTools.Core.Bonk
+{
+    public interface IMultiShape2D : IHasAABB2D
+    {
+        IEnumerable<(IShape2D, Transform2D)> ShapeTransformPairs { get; }
+    }
+}

Bonk/IShape2D.cs

@@ -4,10 +4,8 @@ using MoonTools.Core.Structs;
 
 namespace MoonTools.Core.Bonk
 {
-    public interface IShape2D : IEquatable<IShape2D>
+    public interface IShape2D : IHasAABB2D, IEquatable<IShape2D>
     {
-        AABB AABB { get; }
-
         /// <summary>
         /// A Minkowski support function. Gives the farthest point on the edge of a shape along the given direction.
         /// </summary>
@@ -15,12 +13,5 @@ namespace MoonTools.Core.Bonk
         /// <param name="transform">A Transform for transforming the shape vertices.</param>
         /// <returns>The farthest point on the edge of the shape along the given direction.</returns>
         Vector2 Support(Vector2 direction, Transform2D transform);
-
-        /// <summary>
-        /// Returns a bounding box based on the shape.
-        /// </summary>
-        /// <param name="transform">A Transform for transforming the shape vertices.</param>
-        /// <returns>Returns a bounding box based on the shape.</returns>
-        AABB TransformedAABB(Transform2D transform);
     }
 }

Bonk/MinkowskiDifference.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Numerics;
 using MoonTools.Core.Structs;
 
@@ -56,4 +56,4 @@ namespace MoonTools.Core.Bonk
             return !(a == b);
         }
     }
-}
+}

Bonk/MultiShapes/MultiRectangle.cs

@@ -0,0 +1,65 @@
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using MoonTools.Core.Structs;
+
+namespace MoonTools.Core.Bonk
+{
+    public struct MultiRectangle : IMultiShape2D
+    {
+        private ImmutableArray<(Rectangle, Transform2D)> Rectangles { get; }
+
+        public IEnumerable<(IShape2D, Transform2D)> ShapeTransformPairs
+        {
+            get
+            {
+                foreach (var rectangle in Rectangles) { yield return rectangle; }
+            }
+        }
+
+        public AABB AABB { get; }
+
+        public MultiRectangle(ImmutableArray<(Rectangle, Transform2D)> rectangles)
+        {
+            Rectangles = rectangles;
+
+            AABB = AABBFromRectangles(rectangles);
+        }
+
+        public AABB TransformedAABB(Transform2D transform)
+        {
+            return AABB.Transformed(AABB, transform);
+        }
+
+        private static AABB AABBFromRectangles(IEnumerable<(Rectangle, Transform2D)> rectangles)
+        {
+            var minX = float.MaxValue;
+            var minY = float.MaxValue;
+            var maxX = float.MinValue;
+            var maxY = float.MinValue;
+
+            foreach (var (rectangle, transform) in rectangles)
+            {
+                var transformedAABB = rectangle.TransformedAABB(transform);
+
+                if (transformedAABB.Min.X < minX)
+                {
+                    minX = transformedAABB.Min.X;
+                }
+                if (transformedAABB.Min.Y < minY)
+                {
+                    minY = transformedAABB.Min.Y;
+                }
+                if (transformedAABB.Max.X > maxX)
+                {
+                    maxX = transformedAABB.Max.X;
+                }
+                if (transformedAABB.Max.Y > maxY)
+                {
+                    maxY = transformedAABB.Max.Y;
+                }
+            }
+
+            return new AABB(minX, minY, maxX, maxY);
+        }
+    }
+}

Bonk/NarrowPhase/NarrowPhase.cs

@@ -35,6 +35,63 @@ namespace MoonTools.Core.Bonk
             return FindCollisionSimplex(shapeA, transformA, shapeB, transformB).Item1;
         }
 
+        /// <summary>
+        /// Tests if a multishape-transform and shape-transform pair are overlapping. 
+        /// Note that this must perform pairwise comparison so the worst-case performance of this method will vary inversely with the amount of shapes in the multishape.
+        /// </summary>
+        /// <param name="multiShape"></param>
+        /// <param name="multiShapeTransform"></param>
+        /// <param name="shape"></param>
+        /// <param name="shapeTransform"></param>
+        /// <returns></returns>
+        public static bool TestCollision(IMultiShape2D multiShape, Transform2D multiShapeTransform, IShape2D shape, Transform2D shapeTransform)
+        {
+            foreach (var (otherShape, otherTransform) in multiShape.ShapeTransformPairs)
+            {
+                if (TestCollision(shape, shapeTransform, otherShape, multiShapeTransform.Compose(otherTransform))) { return true; }
+            }
+            return false;
+        }
+
+        /// <summary>
+        /// Tests if a multishape-transform and shape-transform pair are overlapping. 
+        /// Note that this must perform pairwise comparison so the worst-case performance of this method will vary inversely with the amount of shapes in the multishape.
+        /// </summary>
+        /// <param name="multiShape"></param>
+        /// <param name="multiShapeTransform"></param>
+        /// <param name="shape"></param>
+        /// <param name="shapeTransform"></param>
+        /// <returns></returns>
+        public static bool TestCollision(IShape2D shape, Transform2D shapeTransform, IMultiShape2D multiShape, Transform2D multiShapeTransform)
+        {
+            foreach (var (otherShape, otherTransform) in multiShape.ShapeTransformPairs)
+            {
+                if (TestCollision(shape, shapeTransform, otherShape, multiShapeTransform.Compose(otherTransform))) { return true; }
+            }
+            return false;
+        }
+
+        /// <summary>
+        /// Tests if two multishape-transform pairs are overlapping. 
+        /// Note that this must perform pairwise comparison so the worst-case performance of this method will vary inversely with the amount of shapes in the multishapes.
+        /// </summary>
+        /// <param name="multiShapeA"></param>
+        /// <param name="transformA"></param>
+        /// <param name="multiShapeB"></param>
+        /// <param name="transformB"></param>
+        /// <returns></returns>
+        public static bool TestCollision(IMultiShape2D multiShapeA, Transform2D transformA, IMultiShape2D multiShapeB, Transform2D transformB)
+        {
+            foreach (var (shapeA, shapeTransformA) in multiShapeA.ShapeTransformPairs)
+            {
+                foreach (var (shapeB, shapeTransformB) in multiShapeB.ShapeTransformPairs)
+                {
+                    if (TestCollision(shapeA, transformA.Compose(shapeTransformA), shapeB, transformB.Compose(shapeTransformB))) { return true; }
+                }
+            }
+            return false;
+        }
+
         /// <summary>
         /// Fast path for axis-aligned rectangles. If the transforms have non-zero rotation this will be inaccurate.
         /// </summary>

Bonk/Shapes/Polygon.cs

@@ -59,7 +59,7 @@ namespace MoonTools.Core.Bonk
 
         public bool Equals(IShape2D other)
         {
-            return (other is Polygon otherPolygon && Equals(otherPolygon)) || (other is Rectangle rectangle && Equals(rectangle));
+            return (other is Polygon otherPolygon && Equals(otherPolygon));
         }
 
         public bool Equals(Polygon other)
@@ -82,11 +82,6 @@ namespace MoonTools.Core.Bonk
             return true;
         }
 
-        public bool Equals(Rectangle rectangle)
-        {
-            return RectanglePolygonComparison.Equals(this, rectangle);
-        }
-
         public override int GetHashCode()
         {
             return HashCode.Combine(Vertices);

Bonk/Shapes/Rectangle.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.Numerics;
 using MoonTools.Core.Structs;
 
@@ -10,47 +9,33 @@ namespace MoonTools.Core.Bonk
     /// </summary>
     public struct Rectangle : IShape2D, IEquatable<Rectangle>
     {
-        /// <summary>
-        /// The minimum position of the rectangle. Note that we assume y-down coordinates.
-        /// </summary>
-        /// <value></value>
-        public Position2D Min { get; }
-        /// <summary>
-        /// The maximum position of the rectangle. Note that we assume y-down coordinates.
-        /// </summary>
-        /// <value></value>
-        public Position2D Max { get; }
         public AABB AABB { get; }
-
-        public int Left { get { return Min.X; } }
-        public int Right { get { return Max.X; } }
-        public int Top { get { return Min.Y; } }
-        public int Bottom { get { return Max.Y; } }
-
         public int Width { get; }
         public int Height { get; }
 
-        public Position2D TopRight { get { return new Position2D(Right, Top); } }
+        public float Right { get; }
-        public Position2D BottomLeft { get { return new Position2D(Left, Bottom); } }
+        public float Left { get; }
+        public float Top { get; }
+        public float Bottom { get; }
+        public Vector2 BottomLeft { get; }
+        public Vector2 TopRight { get; }
 
-        public IEnumerable<Position2D> Vertices
+        public Vector2 Min { get; }
-        {
+        public Vector2 Max { get; }
-            get
-            {
-                yield return new Position2D(Min.X, Min.Y);
-                yield return new Position2D(Min.X, Max.Y);
-                yield return new Position2D(Max.X, Min.Y);
-                yield return new Position2D(Max.X, Max.Y);
-            }
-        }
 
-        public Rectangle(int minX, int minY, int maxX, int maxY)
+        public Rectangle(int width, int height)
         {
-            Min = new Position2D(minX, minY);
+            Width = width;
-            Max = new Position2D(maxX, maxY);
+            Height = height;
-            AABB = new AABB(minX, minY, maxX, maxY);
+            AABB = new AABB(-width / 2f, -height / 2f, width / 2f, height / 2f);
-            Width = Max.X - Min.X;
+            Right = AABB.Right;
-            Height = Max.Y - Min.Y;
+            Left = AABB.Left;
+            Top = AABB.Top;
+            Bottom = AABB.Bottom;
+            BottomLeft = new Vector2(Left, Bottom);
+            TopRight = new Vector2(Top, Right);
+            Min = AABB.Min;
+            Max = AABB.Max;
         }
 
         private Vector2 Support(Vector2 direction)
@@ -97,7 +82,7 @@ namespace MoonTools.Core.Bonk
 
         public bool Equals(IShape2D other)
         {
-            return (other is Rectangle rectangle && Equals(rectangle)) || (other is Polygon polygon && Equals(polygon));
+            return (other is Rectangle rectangle && Equals(rectangle));
         }
 
         public bool Equals(Rectangle other)
@@ -105,11 +90,6 @@ namespace MoonTools.Core.Bonk
             return Min == other.Min && Max == other.Max;
         }
 
-        public bool Equals(Polygon other)
-        {
-            return RectanglePolygonComparison.Equals(other, this);
-        }
-
         public override int GetHashCode()
         {
             return HashCode.Combine(Min, Max);

Bonk/Shapes/RectanglePolygonComparison.cs

@@ -1,25 +0,0 @@
-using MoonTools.Core.Structs;
-
-namespace MoonTools.Core.Bonk
-{
-    internal static class RectanglePolygonComparison
-    {
-        public static bool Equals(Polygon polygon, Rectangle rectangle)
-        {
-            if (polygon.VertexCount != 4) { return false; }
-
-            int? minIndex = null;
-            for (var i = 0; i < 4; i++)
-            {
-                if (polygon.Vertices[i] == rectangle.Min) { minIndex = i; break; }
-            }
-
-            if (!minIndex.HasValue) { return false; }
-
-            return
-                polygon.Vertices[(minIndex.Value + 1) % 4] == rectangle.TopRight &&
-                polygon.Vertices[(minIndex.Value + 2) % 4] == rectangle.Max &&
-                polygon.Vertices[(minIndex.Value + 3) % 4] == rectangle.BottomLeft;
-        }
-    }
-}

Test/AABBTest.cs

@@ -14,6 +14,11 @@ namespace Tests
             var b = new AABB(new Vector2(0, 0), new Vector2(2, 2));
 
             AABB.TestOverlap(a, b).Should().BeTrue();
+
+            var c = new AABB(-2, -2, 2, 1);
+            var d = new AABB(-2, -2, 2, 2);
+
+            AABB.TestOverlap(c, d).Should().BeTrue();
         }
 
         [Test]

Test/EPA2DTest.cs

@@ -13,9 +13,9 @@ namespace Tests
         [Test]
         public void RectangleOverlap()
         {
-            var squareA = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var squareA = new Rectangle(2, 2);
             var transformA = Transform2D.DefaultTransform;
-            var squareB = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var squareB = new Rectangle(2, 2);
             var transformB = new Transform2D(new Vector2(1.5f, 0));
 
             var (result, simplex) = NarrowPhase.FindCollisionSimplex(squareA, transformA, squareB, transformB);
@@ -62,7 +62,7 @@ namespace Tests
         {
             var line = new Line(new Position2D(-4, -4), new Position2D(4, 4));
             var transformA = Transform2D.DefaultTransform;
-            var square = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var square = new Rectangle(2, 2);
             var transformB = Transform2D.DefaultTransform;
 
             var (result, simplex) = NarrowPhase.FindCollisionSimplex(line, transformA, square, transformB);

Test/Equality.cs

@@ -140,8 +140,8 @@ namespace Tests
             [Test]
             public void RectangleEqual()
             {
-                var a = new Rectangle(0, 0, 3, 3);
+                var a = new Rectangle(3, 3);
-                var b = new Rectangle(0, 0, 3, 3);
+                var b = new Rectangle(3, 3);
 
                 a.Equals(b).Should().BeTrue();
             }
@@ -149,8 +149,8 @@ namespace Tests
             [Test]
             public void RectangleEqualOperator()
             {
-                var a = new Rectangle(0, 0, 3, 3);
+                var a = new Rectangle(3, 3);
-                var b = new Rectangle(0, 0, 3, 3);
+                var b = new Rectangle(3, 3);
 
                 (a == b).Should().BeTrue();
             }
@@ -158,8 +158,8 @@ namespace Tests
             [Test]
             public void RectangleNotEqual()
             {
-                var a = new Rectangle(0, 0, 3, 3);
+                var a = new Rectangle(3, 3);
-                var b = new Rectangle(-1, -1, 5, 5);
+                var b = new Rectangle(6, 6);
 
                 a.Equals(b).Should().BeFalse();
             }
@@ -167,8 +167,8 @@ namespace Tests
             [Test]
             public void RectangleNotEqualOperator()
             {
-                var a = new Rectangle(0, 0, 3, 3);
+                var a = new Rectangle(3, 3);
-                var b = new Rectangle(-1, -1, 5, 5);
+                var b = new Rectangle(6, 6);
 
                 (a != b).Should().BeTrue();
             }
@@ -283,70 +283,6 @@ namespace Tests
 
                 (a != b).Should().BeTrue();
             }
-
-            [Test]
-            public void PolygonRectangleEqual()
-            {
-                var a = new Polygon(ImmutableArray.Create(
-                    new Position2D(-1, -1),
-                    new Position2D(1, -1),
-                    new Position2D(1, 1),
-                    new Position2D(-1, 1)
-                ));
-
-                var b = new Rectangle(-1, -1, 1, 1);
-
-                a.Equals(b).Should().BeTrue();
-                b.Equals(a).Should().BeTrue();
-            }
-
-            [Test]
-            public void PolygonRectangleNotEqual()
-            {
-                var a = new Polygon(ImmutableArray.Create(
-                    new Position2D(-2, -1),
-                    new Position2D(1, -1),
-                    new Position2D(1, 1),
-                    new Position2D(-2, 1)
-                ));
-
-                var b = new Rectangle(-1, -1, 1, 1);
-
-                a.Equals(b).Should().BeFalse();
-                b.Equals(a).Should().BeFalse();
-            }
-
-            [Test]
-            public void PolygonRectangleEqualOperator()
-            {
-                var a = new Polygon(ImmutableArray.Create(
-                    new Position2D(-1, -1),
-                    new Position2D(1, -1),
-                    new Position2D(1, 1),
-                    new Position2D(-1, 1)
-                ));
-
-                var b = new Rectangle(-1, -1, 1, 1);
-
-                (a == b).Should().BeTrue();
-                (b == a).Should().BeTrue();
-            }
-
-            [Test]
-            public void PolygonRectangleNotEqualOperator()
-            {
-                var a = new Polygon(ImmutableArray.Create(
-                    new Position2D(2, 1),
-                    new Position2D(1, -1),
-                    new Position2D(-1, -1),
-                    new Position2D(-2, 1)
-                ));
-
-                var b = new Rectangle(-1, -1, 1, 1);
-
-                (a != b).Should().BeTrue();
-                (b != a).Should().BeTrue();
-            }
         }
 
         public class SimplexTests

Test/NarrowPhaseTest.cs

@@ -7,7 +7,7 @@ using System.Collections.Immutable;
 
 namespace Tests
 {
-    public class GJK2DTest
+    public class NarrowPhaseTest
     {
         [Test]
         public void PointLineOverlapping()
@@ -55,7 +55,7 @@ namespace Tests
         public void PointRectangleOverlapping()
         {
             var point = new Point();
-            var rectangle = new Rectangle(-2, -2, 2, 2);
+            var rectangle = new Rectangle(4, 4);
 
             NarrowPhase.TestCollision(point, Transform2D.DefaultTransform, rectangle, Transform2D.DefaultTransform).Should().BeTrue();
         }
@@ -65,7 +65,7 @@ namespace Tests
         {
             var point = new Point();
             var pointTransform = new Transform2D(new Position2D(5, 5));
-            var rectangle = new Rectangle(-2, -2, 2, 2);
+            var rectangle = new Rectangle(4, 4);
 
             NarrowPhase.TestCollision(point, pointTransform, rectangle, Transform2D.DefaultTransform).Should().BeFalse();
         }
@@ -354,10 +354,10 @@ namespace Tests
         [Test]
         public void RectanglesNotOverlapping()
         {
-            var rectangleA = new MoonTools.Core.Bonk.Rectangle(-6, -6, 6, 6);
+            var rectangleA = new Rectangle(12, 12);
             var transformA = new Transform2D(new Position2D(39, 249));
 
-            var rectangleB = new MoonTools.Core.Bonk.Rectangle(0, 0, 16, 16);
+            var rectangleB = new Rectangle(16, 16);
             var transformB = new Transform2D(new Position2D(16, 240));
 
             NarrowPhase.TestCollision(rectangleA, transformA, rectangleB, transformB).Should().BeFalse();
@@ -366,10 +366,10 @@ namespace Tests
         [Test]
         public void RotatedRectanglesOverlapping()
         {
-            var rectangleA = new MoonTools.Core.Bonk.Rectangle(-1, -1, 2, 2);
+            var rectangleA = new Rectangle(3, 3);
             var transformA = new Transform2D(new Vector2(-1, 0), -90f);
 
-            var rectangleB = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var rectangleB = new Rectangle(2, 2);
             var transformB = new Transform2D(new Vector2(1, 0));
 
             NarrowPhase.TestCollision(rectangleA, transformA, rectangleB, transformB).Should().BeTrue();
@@ -378,10 +378,10 @@ namespace Tests
         [Test]
         public void RectanglesTouchingGJK2D()
         {
-            var rectangleA = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var rectangleA = new Rectangle(2, 2);
             var transformA = new Transform2D(new Position2D(-1, 0));
 
-            var rectangleB = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var rectangleB = new Rectangle(2, 2);
             var transformB = new Transform2D(new Vector2(1, 0));
 
             NarrowPhase.TestCollision(rectangleA, transformA, rectangleB, transformB).Should().BeTrue();
@@ -390,10 +390,10 @@ namespace Tests
         [Test]
         public void RectanglesOverlappingGJK2D()
         {
-            var rectangleA = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var rectangleA = new Rectangle(2, 2);
             var transformA = new Transform2D(new Position2D(0, 0));
 
-            var rectangleB = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var rectangleB = new Rectangle(2, 2);
             var transformB = new Transform2D(new Vector2(1, 0));
 
             NarrowPhase.TestCollision(rectangleA, transformA, rectangleB, transformB).Should().BeTrue();
@@ -402,10 +402,10 @@ namespace Tests
         [Test]
         public void RectanglesTouchingOverlap()
         {
-            var rectangleA = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var rectangleA = new Rectangle(2, 2);
             var transformA = new Transform2D(new Position2D(-1, 0));
 
-            var rectangleB = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var rectangleB = new Rectangle(2, 2);
             var transformB = new Transform2D(new Vector2(1, 0));
 
             NarrowPhase.TestRectangleOverlap(rectangleA, transformA, rectangleB, transformB).Should().BeTrue();
@@ -414,13 +414,61 @@ namespace Tests
         [Test]
         public void RectanglesOverlappingOverlap()
         {
-            var rectangleA = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var rectangleA = new Rectangle(2, 2);
             var transformA = new Transform2D(new Position2D(0, 0));
 
-            var rectangleB = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
+            var rectangleB = new Rectangle(2, 2);
             var transformB = new Transform2D(new Vector2(1, 0));
 
             NarrowPhase.TestRectangleOverlap(rectangleA, transformA, rectangleB, transformB).Should().BeTrue();
         }
+
+        [Test]
+        public void MultiRectanglesOverlapping()
+        {
+            var multiRectangleA = new MultiRectangle(
+                ImmutableArray.Create(
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(-5, 0))),
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(-5, 1))),
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(-5, 2)))
+                )
+            );
+            var transformA = new Transform2D(new Position2D(5, 0));
+
+            var multiRectangleB = new MultiRectangle(
+                ImmutableArray.Create(
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(4, -1))),
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(4, 0))),
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(4, 1)))
+                )
+            );
+            var transformB = new Transform2D(new Position2D(0, 3));
+
+            NarrowPhase.TestCollision(multiRectangleA, transformA, multiRectangleB, transformB).Should().BeTrue();
+        }
+
+        [Test]
+        public void MultiRectanglesNotOverlapping()
+        {
+            var multiRectangleA = new MultiRectangle(
+                ImmutableArray.Create(
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(-5, 0))),
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(-5, 1))),
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(-5, 2)))
+                )
+            );
+            var transformA = new Transform2D(new Position2D(5, 0));
+
+            var multiRectangleB = new MultiRectangle(
+                ImmutableArray.Create(
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(4, -1))),
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(4, 0))),
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(4, 1)))
+                )
+            );
+            var transformB = new Transform2D(new Position2D(0, -3));
+
+            NarrowPhase.TestCollision(multiRectangleA, transformA, multiRectangleB, transformB).Should().BeFalse();
+        }
     }
 }

Test/SpatialHashTest.cs

@@ -3,6 +3,7 @@ using NUnit.Framework;
 using MoonTools.Core.Structs;
 using MoonTools.Core.Bonk;
 using System.Numerics;
+using System.Collections.Immutable;
 
 namespace Tests
 {
@@ -13,16 +14,16 @@ namespace Tests
         {
             var spatialHash = new SpatialHash<int>(16);
 
-            var rectA = new Rectangle(-2, -2, 2, 2);
+            var rectA = new Rectangle(4, 4);
             var rectATransform = new Transform2D(new Vector2(-8, -8));
 
-            var rectB = new Rectangle(-2, -2, 2, 2);
+            var rectB = new Rectangle(4, 4);
             var rectBTransform = new Transform2D(new Vector2(8, 8));
 
-            var rectC = new Rectangle(-2, -2, 2, 2);
+            var rectC = new Rectangle(4, 4);
             var rectCTransform = new Transform2D(new Vector2(24, -4));
 
-            var rectD = new Rectangle(-2, -2, 2, 2);
+            var rectD = new Rectangle(4, 4);
             var rectDTransform = new Transform2D(new Vector2(24, 24));
 
             var circleA = new Circle(2);
@@ -37,25 +38,38 @@ namespace Tests
             var point = new Point();
             var pointTransform = new Transform2D(new Position2D(8, 8));
 
+            var multiRectangle = new MultiRectangle(
+                ImmutableArray.Create(
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(-2, -2))),
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(-2, -1))),
+                    (new Rectangle(4, 1), new Transform2D(new Position2D(-2, 0)))
+                )
+            );
+            var multiRectangleTransform = new Transform2D(new Position2D(8, 8));
+
             spatialHash.Insert(0, rectA, rectATransform);
             spatialHash.Insert(1, rectB, rectBTransform);
             spatialHash.Insert(2, rectC, rectCTransform);
             spatialHash.Insert(3, rectD, rectDTransform);
             spatialHash.Insert(4, circleA, circleATransform);
-            spatialHash.Insert(1, circleB, circleBTransform);
+            spatialHash.Insert(9, circleB, circleBTransform);
             spatialHash.Insert(6, line, lineTransform);
             spatialHash.Insert(7, point, pointTransform);
+            spatialHash.Insert(8, multiRectangle, multiRectangleTransform);
 
             spatialHash.Retrieve(0, rectA, rectATransform).Should().BeEmpty();
             spatialHash.Retrieve(1, rectB, rectBTransform).Should().NotContain((1, circleB, circleBTransform));
             spatialHash.Retrieve(1, rectB, rectBTransform).Should().Contain((7, point, pointTransform));
+            spatialHash.Retrieve(1, rectB, rectBTransform).Should().Contain((8, multiRectangle, multiRectangleTransform));
             spatialHash.Retrieve(2, rectC, rectCTransform).Should().Contain((6, line, lineTransform)).And.Contain((4, circleA, circleATransform));
-            spatialHash.Retrieve(3, rectD, rectDTransform).Should().Contain((1, circleB, circleBTransform));
+            spatialHash.Retrieve(3, rectD, rectDTransform).Should().Contain((9, circleB, circleBTransform));
 
             spatialHash.Retrieve(4, circleA, circleATransform).Should().Contain((6, line, lineTransform)).And.Contain((2, rectC, rectCTransform));
             spatialHash.Retrieve(1, circleB, circleBTransform).Should().NotContain((1, rectB, rectBTransform)).And.Contain((3, rectD, rectDTransform));
 
             spatialHash.Retrieve(6, line, lineTransform).Should().Contain((4, circleA, circleATransform)).And.Contain((2, rectC, rectCTransform));
+
+            spatialHash.Retrieve(8, multiRectangle, multiRectangleTransform).Should().Contain((1, rectB, rectBTransform));
         }
 
         [Test]
@@ -63,13 +77,13 @@ namespace Tests
         {
             var spatialHash = new SpatialHash<int>(16);
 
-            var rectA = new Rectangle(-2, -2, 2, 2);
+            var rectA = new Rectangle(4, 4);
             var rectATransform = new Transform2D(new Vector2(-8, -8));
 
-            var rectB = new Rectangle(-2, -2, 2, 2);
+            var rectB = new Rectangle(4, 4);
             var rectBTransform = new Transform2D(new Vector2(-8, -8));
 
-            var rectC = new Rectangle(-1, -1, 1, 1);
+            var rectC = new Rectangle(2, 2);
             var rectCTransform = new Transform2D(new Vector2(-8, -8));
 
             spatialHash.Insert(0, rectA, rectATransform);
@@ -84,10 +98,10 @@ namespace Tests
         {
             var spatialHash = new SpatialHash<int>(16);
 
-            var rectA = new Rectangle(-2, -2, 2, 2);
+            var rectA = new Rectangle(4, 4);
             var rectATransform = new Transform2D(new Vector2(-8, -8));
 
-            var rectB = new Rectangle(-2, -2, 2, 2);
+            var rectB = new Rectangle(4, 4);
             var rectBTransform = new Transform2D(new Vector2(8, 8));
 
             spatialHash.Insert(0, rectA, rectATransform);