Add GetSplineDirection util to Spline

Source/Engine/Level/Actors/Spline.cpp

@@ -77,6 +77,21 @@ Transform Spline::GetSplineLocalTransform(float time) const
     return t;
 }
 
+Vector3 Spline::GetSplineDirection(float time) const
+{
+    return _transform.LocalToWorldVector(GetSplineLocalDirection(time));
+}
+
+Vector3 Spline::GetSplineLocalDirection(float time) const
+{
+    if (Curve.GetKeyframes().Count() == 0)
+        return Vector3::Forward;
+    Transform t;
+    Curve.EvaluateFirstDerivative(t, time, _loop);
+    t.Translation.Normalize();
+    return t.Translation;
+}
+
 Vector3 Spline::GetSplinePoint(int32 index) const
 {
     CHECK_RETURN(index >= 0 && index < GetSplinePointsCount(), Vector3::Zero)

Source/Engine/Level/Actors/Spline.h

@@ -96,6 +96,20 @@ public:
     /// <returns>The calculated curve point transformation (local-space).</returns>
     API_FUNCTION() Transform GetSplineLocalTransform(float time) const;
 
+    /// <summary>
+    /// Evaluates the spline curve direction (forward vector, aka position 1st derivative) at the given time in 3D (world-space).
+    /// </summary>
+    /// <param name="time">The time value. Can be negative or larger than curve length (curve will loop or clamp).</param>
+    /// <returns>The calculated curve direction (world-space).</returns>
+    API_FUNCTION() Vector3 GetSplineDirection(float time) const;
+
+    /// <summary>
+    /// Evaluates the spline curve direction (forward vector, aka position 1st derivative) at the given time in 3D (local-space).
+    /// </summary>
+    /// <param name="time">The time value. Can be negative or larger than curve length (curve will loop or clamp).</param>
+    /// <returns>The calculated curve direction (local-space).</returns>
+    API_FUNCTION() Vector3 GetSplineLocalDirection(float time) const;
+
     /// <summary>
     /// Evaluates the spline curve at the given index (world-space).
     /// </summary>