From 540681e59d5e51e85f1af0e462fa85da44a2a36a Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Thu, 31 Aug 2023 09:23:16 +0200
Subject: [PATCH] Add `MoveTowards` to vector3

---
 Source/Engine/Core/Math/Double3.cs | 17 +++++++++++++++++
 Source/Engine/Core/Math/Float3.cs  | 17 +++++++++++++++++
 Source/Engine/Core/Math/Vector3.cs | 17 +++++++++++++++++
 Source/Engine/Core/Math/Vector3.h  | 17 +++++++++++++++++
 4 files changed, 68 insertions(+)

diff --git a/Source/Engine/Core/Math/Double3.cs b/Source/Engine/Core/Math/Double3.cs
index eb41ad400..ca5eb9cbd 100644
--- a/Source/Engine/Core/Math/Double3.cs
+++ b/Source/Engine/Core/Math/Double3.cs
@@ -1054,6 +1054,23 @@ namespace FlaxEngine
             return result;
         }
 
+        /// <summary>
+        /// Moves a value current towards target.
+        /// </summary>
+        /// <param name="current">The position to move from.</param>
+        /// <param name="target">The position to move towards.</param>
+        /// <param name="maxDistanceDelta">The maximum distance that can be applied to the value.</param>
+        /// <returns>The new position.</returns>
+        public static Double3 MoveTowards(Double3 current, Double3 target, double maxDistanceDelta)
+        {
+            var to = target - current;
+            var distanceSq = to.LengthSquared;
+            if (distanceSq == 0 || (maxDistanceDelta >= 0 && distanceSq <= maxDistanceDelta * maxDistanceDelta))
+                return target;
+            var scale = maxDistanceDelta / Mathd.Sqrt(distanceSq);
+            return new Double3(current.X + to.X * scale, current.Y + to.Y * scale, current.Z + to.Z * scale);
+        }
+
         /// <summary>
         /// Performs a Hermite spline interpolation.
         /// </summary>
diff --git a/Source/Engine/Core/Math/Float3.cs b/Source/Engine/Core/Math/Float3.cs
index 1831a3b99..3ea95f0d7 100644
--- a/Source/Engine/Core/Math/Float3.cs
+++ b/Source/Engine/Core/Math/Float3.cs
@@ -1038,6 +1038,23 @@ namespace FlaxEngine
             return result;
         }
 
+        /// <summary>
+        /// Moves a value current towards target.
+        /// </summary>
+        /// <param name="current">The position to move from.</param>
+        /// <param name="target">The position to move towards.</param>
+        /// <param name="maxDistanceDelta">The maximum distance that can be applied to the value.</param>
+        /// <returns>The new position.</returns>
+        public static Float3 MoveTowards(Float3 current, Float3 target, float maxDistanceDelta)
+        {
+            var to = target - current;
+            var distanceSq = to.LengthSquared;
+            if (distanceSq == 0 || (maxDistanceDelta >= 0 && distanceSq <= maxDistanceDelta * maxDistanceDelta))
+                return target;
+            var scale = maxDistanceDelta / Mathf.Sqrt(distanceSq);
+            return new Float3(current.X + to.X * scale, current.Y + to.Y * scale, current.Z + to.Z * scale);
+        }
+
         /// <summary>
         /// Performs a Hermite spline interpolation.
         /// </summary>
diff --git a/Source/Engine/Core/Math/Vector3.cs b/Source/Engine/Core/Math/Vector3.cs
index 4442d3334..72f538269 100644
--- a/Source/Engine/Core/Math/Vector3.cs
+++ b/Source/Engine/Core/Math/Vector3.cs
@@ -1068,6 +1068,23 @@ namespace FlaxEngine
             return result;
         }
 
+        /// <summary>
+        /// Moves a value current towards target.
+        /// </summary>
+        /// <param name="current">The position to move from.</param>
+        /// <param name="target">The position to move towards.</param>
+        /// <param name="maxDistanceDelta">The maximum distance that can be applied to the value.</param>
+        /// <returns>The new position.</returns>
+        public static Vector3 MoveTowards(Vector3 current, Vector3 target, float maxDistanceDelta)
+        {
+            var to = target - current;
+            var distanceSq = to.LengthSquared;
+            if (distanceSq == 0 || (maxDistanceDelta >= 0 && distanceSq <= maxDistanceDelta * maxDistanceDelta))
+                return target;
+            var scale = maxDistanceDelta / Mathr.Sqrt(distanceSq);
+            return new Vector3(current.X + to.X * scale, current.Y + to.Y * scale, current.Z + to.Z * scale);
+        }
+
         /// <summary>
         /// Performs a Hermite spline interpolation.
         /// </summary>
diff --git a/Source/Engine/Core/Math/Vector3.h b/Source/Engine/Core/Math/Vector3.h
index cad5250b7..c0ebdf01d 100644
--- a/Source/Engine/Core/Math/Vector3.h
+++ b/Source/Engine/Core/Math/Vector3.h
@@ -727,6 +727,23 @@ public:
         Lerp(start, end, amount, result);
     }
 
+    /// <summary>
+    /// Moves a value current towards target.
+    /// </summary>
+    /// <param name="current">The position to move from.</param>
+    /// <param name="target">The position to move towards.</param>
+    /// <param name="maxDistanceDelta">The maximum distance that can be applied to the value.</param>
+    /// <returns>The new position.</returns>
+    static Vector3 MoveTowards(Vector3 current, Vector3 target, float maxDistanceDelta)
+    {
+        const Vector3Base to = target - current;
+        const T distanceSq = to.LengthSquared();
+        if (distanceSq == 0 || (maxDistanceDelta >= 0 && distanceSq <= maxDistanceDelta * maxDistanceDelta))
+            return target;
+        const T scale = maxDistanceDelta / Math::Sqrt(distanceSq);
+        return Vector3Base(current.X + to.X * scale, current.Y + to.Y * scale, current.Z + to.Z * scale);
+    }
+
     // Performs a Hermite spline interpolation.
     // @param value1 First source position vector
     // @param tangent1 First source tangent vector