tasty restructuring

Bonk/GJK2D.cs

@@ -1,75 +1,61 @@
 using Microsoft.Xna.Framework;
 using MoonTools.Core.Structs;
-using System;
 using MoonTools.Core.Bonk.Extensions;
 
 namespace MoonTools.Core.Bonk
 {
-
-
     public static class GJK2D
     {
         public static bool TestCollision(IShape2D shapeA, Transform2D transformA, IShape2D shapeB, Transform2D transformB)
         {
             var minkowskiDifference = new MinkowskiDifference(shapeA, transformA, shapeB, transformB);
-            return OriginInside(minkowskiDifference);
-        }
-
-        public static (bool, Simplex) CollisionAndSimplex(IShape2D shapeA, Transform2D transformA, IShape2D shapeB, Transform2D transformB)
-        {
-            var minkowskiDifference = new MinkowskiDifference(shapeA, transformA, shapeB, transformB);
-            var (collision, a, b) = OriginInsideWithSimplex(minkowskiDifference);
-            var polytope = new Simplex(minkowskiDifference, a, b);
-            return (collision, polytope);
-        }
-
-        private static Vector2 MinkowskiDifference(Vector2 direction, IShape2D shapeA, Transform2D transformA, IShape2D shapeB, Transform2D transformB)
-        {
-            return shapeA.Support(direction, transformA) - shapeB.Support(-direction, transformB);
-        }
-
-        private static bool OriginInside(MinkowskiDifference minkowskiDifference)
-        {
             var a = minkowskiDifference.Support(Vector2.UnitX);
             var b = minkowskiDifference.Support(-a);
 
-            return Vector2.Dot(a, b) > 0 ? false : CheckSimplex(minkowskiDifference.Support, a, b);
+            return Vector2.Dot(a, b) > 0 ? false : CheckSimplex(new Simplex(minkowskiDifference, a, b));
         }
 
-        private static (bool, Vector2, Vector2) OriginInsideWithSimplex(MinkowskiDifference minkowskiDifference)
+        private static bool CheckSimplex(Simplex simplex)
         {
-            var a = minkowskiDifference.Support(Vector2.UnitX);
+            var a = simplex.DirectionA;
-            var b = minkowskiDifference.Support(-a);
+            var b = simplex.DirectionB;
 
-            return Vector2.Dot(a, b) > 0 ? (false, a, b) : Simplex(minkowskiDifference.Support, a, b);
-        }
-
-        private static bool CheckSimplex(Func<Vector2, Vector2> support, Vector2 a, Vector2 b)
-        {
             var axb = a.Cross(b);
-            var c = support((b - a).Perpendicular());
+            var c = simplex.Support((b - a).Perpendicular());
             var axc = a.Cross(c);
             var bxc = b.Cross(c);
             var cxb = -bxc;
 
-            return (b - a) == Vector2.Zero || (axb.Y > 0 != bxc.Y > 0 ? CheckSimplex(support, b, c) : (axc.Y > 0 != cxb.Y > 0 ? CheckSimplex(support, a, c) : true));
+            return (b - a) == Vector2.Zero || (axb.Y > 0 != bxc.Y > 0 ? CheckSimplex(simplex.WithDirections(b, c)) : (axc.Y > 0 != cxb.Y > 0 ? CheckSimplex(simplex.WithDirections(a, c)) : true));
         }
 
-        private static (bool, Vector2, Vector2) Simplex(Func<Vector2, Vector2> support, Vector2 a, Vector2 b)
+        public static (bool, Simplex) FindCollisionSimplex(IShape2D shapeA, Transform2D transformA, IShape2D shapeB, Transform2D transformB)
         {
+            var minkowskiDifference = new MinkowskiDifference(shapeA, transformA, shapeB, transformB);
+            var a = minkowskiDifference.Support(Vector2.UnitX);
+            var b = minkowskiDifference.Support(-a);
+
+            return Vector2.Dot(a, b) > 0 ? (false, default(Simplex)) : Simplex(new Simplex(minkowskiDifference, a, b));
+        }
+
+        private static (bool, Simplex) Simplex(Simplex simplex)
+        {
+            var a = simplex.DirectionA;
+            var b = simplex.DirectionB;
+
             if ((b - a) == Vector2.Zero)
             {
-                return (false, a, b);
+                return (false, simplex.WithDirections(a, b));
             }
             else
             {
-                var c = support((b - a).Perpendicular());
+                var c = simplex.Support((b - a).Perpendicular());
                 var axb = a.Cross(b);
                 var bxc = b.Cross(c);
 
                 if (axb.Y > 0 != bxc.Y > 0)
                 {
-                    return Simplex(support, b, c);
+                    return Simplex(simplex.WithDirections(b, c));
                 }
                 else
                 {
@@ -78,11 +64,11 @@ namespace MoonTools.Core.Bonk
 
                     if (axc.Y > 0 != cxb.Y > 0)
                     {
-                        return Simplex(support, a, b);
+                        return Simplex(simplex.WithDirections(a, b));
                     }
                     else
                     {
-                        return (true, a, b);
+                        return (true, simplex.WithDirections(a, b));
                     }
                 }
             }

Bonk/Shapes/Simplex.cs

@@ -11,6 +11,9 @@ namespace MoonTools.Core.Bonk
         Vector2 directionA;
         Vector2 directionB;
 
+        public Vector2 DirectionA { get { return directionA; } }
+        public Vector2 DirectionB { get { return directionB; } }
+
         public Simplex(MinkowskiDifference minkowskiDifference, Vector2 directionA, Vector2 directionB)
         {
             this.minkowskiDifference = minkowskiDifference;
@@ -18,6 +21,11 @@ namespace MoonTools.Core.Bonk
             this.directionB = directionB;
         }
 
+        public Simplex WithDirections(Vector2 a, Vector2 b)
+        {
+            return new Simplex(minkowskiDifference, a, b);
+        }
+
         public IEnumerable<Position2D> Vertices
         {
             get

Test/EPA2DTest.cs

@@ -18,7 +18,7 @@ namespace Tests
             var squareB = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
             var transformB = new Transform2D(new Vector2(1.5f, 0));
 
-            var (result, simplex) = GJK2D.CollisionAndSimplex(squareA, transformA, squareB, transformB);
+            var (result, simplex) = GJK2D.FindCollisionSimplex(squareA, transformA, squareB, transformB);
 
             result.Should().BeTrue();
 
@@ -36,7 +36,7 @@ namespace Tests
             var circleB = new Circle(1);
             var transformB = new Transform2D(new Vector2(1, 1));
 
-            var (result, simplex) = GJK2D.CollisionAndSimplex(circleA, transformA, circleB, transformB);
+            var (result, simplex) = GJK2D.FindCollisionSimplex(circleA, transformA, circleB, transformB);
 
             result.Should().BeTrue();
 
@@ -57,7 +57,7 @@ namespace Tests
             var square = new MoonTools.Core.Bonk.Rectangle(-1, -1, 1, 1);
             var transformB = Transform2D.DefaultTransform;
 
-            var (result, simplex) = GJK2D.CollisionAndSimplex(line, transformA, square, transformB);
+            var (result, simplex) = GJK2D.FindCollisionSimplex(line, transformA, square, transformB);
 
             result.Should().BeTrue();