implements efficient equality comparators

.circleci/config.yml

@@ -3,7 +3,7 @@ version: 2.1
 defaults: &defaults
   working_directory: ~/repo
   docker:
-    - image: mcr.microsoft.com/dotnet/core/sdk:2.2
+    - image: mcr.microsoft.com/dotnet/core/sdk:3.0
       environment:
         DOTNET_SKIP_FIRST_TIME_EXPERIENCE: 1
         DOTNET_CLI_TELEMETRY_OPTOUT: 1

Structs/Position2D.cs

@@ -3,7 +3,7 @@ using Microsoft.Xna.Framework;
 
 namespace MoonTools.Core.Structs
 {
-    public struct Position2D
+    public struct Position2D : System.IEquatable<Position2D>
     {
         private Vector2 remainder;
 
@@ -146,5 +146,37 @@ namespace MoonTools.Core.Structs
         {
             return (int)Math.Floor(value);
         }
+
+        public override bool Equals(object other)
+        {
+            if (other is Position2D otherPosition)
+            {
+                return Equals(otherPosition);
+            }
+
+            return false;
+        }
+
+        public bool Equals(Position2D other)
+        {
+            return
+                X == other.X &&
+                Y == other.Y;
+        }
+
+        public override int GetHashCode()
+        {
+            return X.GetHashCode() ^ Y.GetHashCode();
+        }
+
+        public static bool operator ==(Position2D a, Position2D b)
+        {
+            return a.Equals(b);
+        }
+
+        public static bool operator !=(Position2D a, Position2D b)
+        {
+            return !(a == b);
+        }
     }
 }

Structs/Transform2D.cs

@@ -58,13 +58,16 @@ namespace MoonTools.Core.Structs
             }
         }
 
-        public static Transform2D DefaultTransform {
-            get {
+        public static Transform2D DefaultTransform
+        {
+            get
+            {
                 return _defaultTransform;
             }
         }
 
-        public Transform2D(Position2D position) {
+        public Transform2D(Position2D position)
+        {
             _position = position;
             _rotation = 0f;
             _scale = new Vector2(1, 1);
@@ -79,7 +82,8 @@ namespace MoonTools.Core.Structs
             TransformMatrix = CreateTransformMatrix(_position, _rotation, _scale);
         }
 
-        public Transform2D(Position2D position, float rotation) {
+        public Transform2D(Position2D position, float rotation)
+        {
             _position = position;
             _rotation = rotation;
             _scale = new Vector2(1, 1);
@@ -94,27 +98,25 @@ namespace MoonTools.Core.Structs
             TransformMatrix = CreateTransformMatrix(_position, _rotation, _scale);
         }
 
-        public Transform2D(Position2D position, float rotation, Vector2 scale) {
+        public Transform2D(Position2D position, float rotation, Vector2 scale)
+        {
             _position = position;
             _rotation = rotation;
             _scale = scale;
             TransformMatrix = CreateTransformMatrix(_position, _rotation, _scale);
         }
 
-        public Transform2D(Vector2 position, float rotation, Vector2 scale) {
+        public Transform2D(Vector2 position, float rotation, Vector2 scale)
+        {
             _position = new Position2D(position.X, position.Y);
             _rotation = rotation;
             _scale = scale;
             TransformMatrix = CreateTransformMatrix(_position, _rotation, _scale);
         }
 
-        public Transform2D Compose(Transform2D other) {
-            return new Transform2D(Position + other.Position, Rotation + other.Rotation, Scale * other.Scale);
-        }
-
-        public bool Equals(Transform2D other)
+        public Transform2D Compose(Transform2D other)
         {
-            return TransformMatrix == other.TransformMatrix;
+            return new Transform2D(Position + other.Position, Rotation + other.Rotation, Scale * other.Scale);
         }
 
         private static Matrix CreateTransformMatrix(Position2D translation, float rotationDegrees, Vector2 scale)
@@ -123,5 +125,35 @@ namespace MoonTools.Core.Structs
                 Matrix.CreateRotationZ(Microsoft.Xna.Framework.MathHelper.ToRadians(rotationDegrees)) *
                 Matrix.CreateTranslation(translation.X, translation.Y, 0);
         }
+
+        public override bool Equals(Object other)
+        {
+            if (other is Transform2D otherTransform)
+            {
+                return Equals(otherTransform);
+            }
+
+            return false;
+        }
+
+        public bool Equals(Transform2D other)
+        {
+            return TransformMatrix == other.TransformMatrix;
+        }
+
+        public override int GetHashCode()
+        {
+            return TransformMatrix.GetHashCode();
+        }
+
+        public static bool operator ==(Transform2D a, Transform2D b)
+        {
+            return a.Equals(b);
+        }
+
+        public static bool operator !=(Transform2D a, Transform2D b)
+        {
+            return !(a == b);
+        }
     }
 }

Tests/Position2DTest.cs

@@ -61,5 +61,41 @@ namespace Tests
             result.X.Should().BeApproximately(1.2f, 0.01f);
             result.Y.Should().BeApproximately(6.4f, 0.01f);
         }
+
+        [Test]
+        public void Equals()
+        {
+            var one = new Position2D(5.2f, 4.7f);
+            var two = new Position2D(5.1f, 4.4f);
+
+            one.Equals(two).Should().BeTrue();
+        }
+
+        [Test]
+        public void EqualsOperator()
+        {
+            var one = new Position2D(5.2f, 4.7f);
+            var two = new Position2D(5.1f, 4.4f);
+
+            (one == two).Should().BeTrue();
+        }
+
+        [Test]
+        public void NotEquals()
+        {
+            var one = new Position2D(5.2f, 4.7f);
+            var two = new Position2D(3.1f, 2.4f);
+
+            one.Equals(two).Should().BeFalse();
+        }
+
+        [Test]
+        public void NotEqualsOperator()
+        {
+            var one = new Position2D(5.2f, 4.7f);
+            var two = new Position2D(3.1f, 2.4f);
+
+            (one != two).Should().BeTrue();
+        }
     }
 }

Tests/Tests.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.2</TargetFramework>
+    <TargetFramework>netcoreapp3.0</TargetFramework>
     <IsPackable>false</IsPackable>
   </PropertyGroup>
   <ItemGroup>

Tests/Transform2DTest.cs

@@ -25,6 +25,24 @@ namespace Tests
             transformA.Should().NotBeEquivalentTo(transformB);
         }
 
+        [Test]
+        public void EqualsOperator()
+        {
+            var transformA = new Transform2D(new Position2D(0, 1), 4f, new Vector2(2, 1));
+            var transformB = new Transform2D(new Position2D(0, 1), 4f, new Vector2(2, 1));
+
+            (transformA == transformB).Should().BeTrue();
+        }
+
+        [Test]
+        public void NotEqualsOperator()
+        {
+            var transformA = new Transform2D(new Position2D(2, 3));
+            var transformB = new Transform2D(new Position2D(5, 1));
+
+            (transformA != transformB).Should().BeTrue();
+        }
+
         [Test]
         public void Compose()
         {