From f0c7fbb0cf04735af77059450d3ebefaf6feca0b Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Wed, 27 Jan 2021 15:28:26 +0100
Subject: [PATCH] Add more utilities for Spline

---
 Source/Engine/Level/Actors/Spline.cpp | 40 +++++++++++++++++++--
 Source/Engine/Level/Actors/Spline.h   | 50 +++++++++++++++++++++++++--
 2 files changed, 86 insertions(+), 4 deletions(-)

diff --git a/Source/Engine/Level/Actors/Spline.cpp b/Source/Engine/Level/Actors/Spline.cpp
index aaccd13fe..a3757253f 100644
--- a/Source/Engine/Level/Actors/Spline.cpp
+++ b/Source/Engine/Level/Actors/Spline.cpp
@@ -106,16 +106,29 @@ Vector3 Spline::GetSplineLocalPoint(int32 index) const
 
 Transform Spline::GetSplineTransform(int32 index) const
 {
-    CHECK_RETURN(index >= 0 && index < GetSplinePointsCount(), Vector3::Zero)
+    CHECK_RETURN(index >= 0 && index < GetSplinePointsCount(), Transform::Identity)
     return _transform.LocalToWorld(Curve[index].Value);
 }
 
 Transform Spline::GetSplineLocalTransform(int32 index) const
 {
-    CHECK_RETURN(index >= 0 && index < GetSplinePointsCount(), Vector3::Zero)
+    CHECK_RETURN(index >= 0 && index < GetSplinePointsCount(), Transform::Identity)
     return Curve[index].Value;
 }
 
+Transform Spline::GetSplineTangent(int32 index, bool isIn)
+{
+    return _transform.LocalToWorld(GetSplineLocalTangent(index, isIn));
+}
+
+Transform Spline::GetSplineLocalTangent(int32 index, bool isIn)
+{
+    CHECK_RETURN(index >= 0 && index < GetSplinePointsCount(), Transform::Identity)
+    const auto& k = Curve[index];
+    const auto& tangent = isIn ? k.TangentIn : k.TangentOut;
+    return tangent + k.Value;
+}
+
 int32 Spline::GetSplinePointsCount() const
 {
     return Curve.GetKeyframes().Count();
@@ -263,6 +276,29 @@ void Spline::SetSplineLocalTransform(int32 index, const Transform& point, bool u
         UpdateSpline();
 }
 
+void Spline::SetSplineTangent(int32 index, const Transform& point, bool isIn, bool updateSpline)
+{
+    SetSplineLocalTangent(index, _transform.WorldToLocal(point), isIn, updateSpline);
+}
+
+void Spline::SetSplineLocalTangent(int32 index, const Transform& point, bool isIn, bool updateSpline)
+{
+    CHECK(index >= 0 && index < GetSplinePointsCount());
+    auto& k = Curve[index];
+    auto& tangent = isIn ? k.TangentIn : k.TangentOut;
+    tangent = point - k.Value;
+    if (updateSpline)
+        UpdateSpline();
+}
+
+void Spline::SetSplinePointTime(int32 index, float time, bool updateSpline)
+{
+    CHECK(index >= 0 && index < GetSplinePointsCount());
+    Curve[index].Time = time;
+    if (updateSpline)
+        UpdateSpline();
+}
+
 void Spline::AddSplinePoint(const Vector3& point, bool updateSpline)
 {
     const Keyframe k(Curve.IsEmpty() ? 0.0f : Curve.GetKeyframes().Last().Time + 1.0f, Transform(_transform.WorldToLocal(point)));
diff --git a/Source/Engine/Level/Actors/Spline.h b/Source/Engine/Level/Actors/Spline.h
index 76f1eddab..772aac821 100644
--- a/Source/Engine/Level/Actors/Spline.h
+++ b/Source/Engine/Level/Actors/Spline.h
@@ -138,6 +138,24 @@ public:
     /// <returns>The curve point transformation (local-space).</returns>
     API_FUNCTION() Transform GetSplineLocalTransform(int32 index) const;
 
+    /// <summary>
+    /// Gets the spline curve point tangent at the given index (world-space).
+    /// </summary>
+    /// <remarks>Tangents are stored relative to the curve point but this methods converts them to be in world-space.</remarks>
+    /// <param name="index">The curve keyframe index. Zero-based, smaller than GetSplinePointsCount().</param>
+    /// <param name="isIn">True if get arrive tangent, otherwise gets leave tangent (in or out).</param>
+    /// <returns>The transformation of the tangent to set (world-space).</returns>
+    API_FUNCTION() Transform GetSplineTangent(int32 index, bool isIn);
+
+    /// <summary>
+    /// Gets the spline curve point tangent at the given index (local-space).
+    /// </summary>
+    /// <remarks>Tangents are stored relative to the curve point but this methods converts them to be in local-space of the actor.</remarks>
+    /// <param name="index">The curve keyframe index. Zero-based, smaller than GetSplinePointsCount().</param>
+    /// <param name="isIn">True if get arrive tangent, otherwise gets leave tangent (in or out).</param>
+    /// <returns>The transformation of the tangent to set (world-space).</returns>
+    API_FUNCTION() Transform GetSplineLocalTangent(int32 index, bool isIn);
+
     /// <summary>
     /// Gets the amount of points in the spline.
     /// </summary>
@@ -218,7 +236,7 @@ public:
     /// Sets the spline curve at the given index (world-space).
     /// </summary>
     /// <param name="index">The curve keyframe index. Zero-based, smaller than GetSplinePointsCount().</param>
-    /// <param name="point">The location of the point to set (world-space).</param>
+    /// <param name="point">The transformation of the point to set (world-space).</param>
     /// <param name="updateSpline">True if update spline after adding the point, otherwise false.</param>
     API_FUNCTION() void SetSplineTransform(int32 index, const Transform& point, bool updateSpline = true);
 
@@ -226,10 +244,38 @@ public:
     /// Sets the spline curve at the given index (local-space).
     /// </summary>
     /// <param name="index">The curve keyframe index. Zero-based, smaller than GetSplinePointsCount().</param>
-    /// <param name="point">The location of the point to set (local-space).</param>
+    /// <param name="point">The transformation of the point to set (local-space).</param>
     /// <param name="updateSpline">True if update spline after adding the point, otherwise false.</param>
     API_FUNCTION() void SetSplineLocalTransform(int32 index, const Transform& point, bool updateSpline = true);
 
+    /// <summary>
+    /// Sets the spline curve point tangent at the given index (world-space).
+    /// </summary>
+    /// <remarks>Tangents are stored relative to the curve point but this methods converts them to be in world-space.</remarks>
+    /// <param name="index">The curve keyframe index. Zero-based, smaller than GetSplinePointsCount().</param>
+    /// <param name="point">The transformation of the tangent to set (world-space).</param>
+    /// <param name="isIn">True if set arrive tangent, otherwise sets leave tangent (in or out).</param>
+    /// <param name="updateSpline">True if update spline after adding the point, otherwise false.</param>
+    API_FUNCTION() void SetSplineTangent(int32 index, const Transform& point, bool isIn, bool updateSpline = true);
+
+    /// <summary>
+    /// Sets the spline curve point tangent at the given index (local-space).
+    /// </summary>
+    /// <remarks>Tangents are stored relative to the curve point but this methods converts them to be in local-space of the actor.</remarks>
+    /// <param name="index">The curve keyframe index. Zero-based, smaller than GetSplinePointsCount().</param>
+    /// <param name="point">The transformation of the tangent to set (local-space).</param>
+    /// <param name="isIn">True if set arrive tangent, otherwise sets leave tangent (in or out).</param>
+    /// <param name="updateSpline">True if update spline after adding the point, otherwise false.</param>
+    API_FUNCTION() void SetSplineLocalTangent(int32 index, const Transform& point, bool isIn, bool updateSpline = true);
+
+    /// <summary>
+    /// Sets the spline curve point time at the given index (world-space).
+    /// </summary>
+    /// <param name="index">The curve keyframe index. Zero-based, smaller than GetSplinePointsCount().</param>
+    /// <param name="time">The time to set.</param>
+    /// <param name="updateSpline">True if update spline after adding the point, otherwise false.</param>
+    API_FUNCTION() void SetSplinePointTime(int32 index, float time, bool updateSpline = true);
+
     /// <summary>
     /// Adds the point to the spline curve (at the end).
     /// </summary>