feat(Extension): add vector direction extension

A Direction extension method for Vector2 and Vector3 will get the
direction vector between a source point and a target point.

Runtime/Extension/Vector2Extensions.cs

@@ -61,5 +61,18 @@ public static Vector2 UnsignedEulerToSignedEuler(this Vector2 eulerAngles)
         {
             return new Vector2(eulerAngles.x.GetSignedDegree(), eulerAngles.y.GetSignedDegree());
         }
+
+        /// <summary>
+        /// Gets the direction from a source to a target.
+        /// </summary>
+        /// <param name="source">The starting point.</param>
+        /// <param name="target">The finishing point.</param>
+        /// <param name="isNormalized">Whether to normalize the direction.</param>
+        /// <returns>The direction that the target is in from the source.</returns>
+        public static Vector2 Direction(this Vector2 source, Vector2 target, bool isNormalized = false)
+        {
+            Vector3 heading = target - source;
+            return heading / (isNormalized ? heading.magnitude : 1f);
+        }
     }
 }

Runtime/Extension/Vector3Extensions.cs

@@ -61,5 +61,18 @@ public static Vector3 UnsignedEulerToSignedEuler(this Vector3 eulerAngles)
         {
             return new Vector3(eulerAngles.x.GetSignedDegree(), eulerAngles.y.GetSignedDegree(), eulerAngles.z.GetSignedDegree());
         }
+
+        /// <summary>
+        /// Gets the direction from a source to a target.
+        /// </summary>
+        /// <param name="source">The starting point.</param>
+        /// <param name="target">The finishing point.</param>
+        /// <param name="isNormalized">Whether to normalize the direction.</param>
+        /// <returns>The direction that the target is in from the source.</returns>
+        public static Vector3 Direction(this Vector3 source, Vector3 target, bool isNormalized = false)
+        {
+            Vector3 heading = target - source;
+            return heading / (isNormalized ? heading.magnitude : 1f);
+        }
     }
 }

Tests/Editor/Extension/Vector2ExtensionsTest.cs

@@ -90,5 +90,15 @@ public void UnsignedEulerToSignedEuler()
             Assert.That(new Vector2(270f, 270f).UnsignedEulerToSignedEuler(), Is.EqualTo(new Vector2(-90f, -90f)).Using(comparer));
             Assert.That(new Vector2(360f, 360f).UnsignedEulerToSignedEuler(), Is.EqualTo(new Vector2(0f, 0f)).Using(comparer));
         }
+
+        [Test]
+        public void Direction()
+        {
+            Vector2 source = Vector2.zero;
+            Vector2 target = new Vector2(1.234f, 3.23f);
+            Vector2EqualityComparer comparer = new Vector2EqualityComparer(0.1f);
+            Assert.That(Vector2Extensions.Direction(source, target), Is.EqualTo(target).Using(comparer));
+            Assert.That(Vector2Extensions.Direction(source, target, true), Is.EqualTo(target.normalized).Using(comparer));
+        }
     }
 }

Tests/Editor/Extension/Vector3ExtensionsTest.cs

@@ -93,5 +93,15 @@ public void UnsignedEulerToSignedEuler()
             Assert.That(new Vector3(270f, 270f, 270f).UnsignedEulerToSignedEuler(), Is.EqualTo(new Vector3(-90f, -90f, -90f)).Using(comparer));
             Assert.That(new Vector3(360f, 360f, 360f).UnsignedEulerToSignedEuler(), Is.EqualTo(new Vector3(0f, 0f, 0f)).Using(comparer));
         }
+
+        [Test]
+        public void Direction()
+        {
+            Vector3 source = Vector3.zero;
+            Vector3 target = new Vector3(1.234f, 3.23f, 2.1234f);
+            Vector3EqualityComparer comparer = new Vector3EqualityComparer(0.1f);
+            Assert.That(Vector3Extensions.Direction(source, target), Is.EqualTo(target).Using(comparer));
+            Assert.That(Vector3Extensions.Direction(source, target, true), Is.EqualTo(target.normalized).Using(comparer));
+        }
     }
 }