From 231948f33f8f3e79f7ae38ab9b3db3e597f13b4a Mon Sep 17 00:00:00 2001
From: Johnny Matthews <guitargeek>
Date: Wed, 15 Sep 2021 13:57:01 -0500
Subject: Splines: Add a method for reversing a Spline

This moved the spline reversing logic out of the Curve Reverse geometry
node and into the spline class. This allows a spline to reverse itself
with a call to `my_spline.reverse()`

The base class will reverse position, radii & tilt, while specialized
versions are created for Bezier and Nurbs splines to reverse the
additional data that these classes encapsulate.

Differential Revision: https://developer.blender.org/D12501
---
 source/blender/blenkernel/BKE_spline.hh | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'source/blender/blenkernel/BKE_spline.hh')

diff --git a/source/blender/blenkernel/BKE_spline.hh b/source/blender/blenkernel/BKE_spline.hh
index fc145f1ddf1..0fbf39a52fa 100644
--- a/source/blender/blenkernel/BKE_spline.hh
+++ b/source/blender/blenkernel/BKE_spline.hh
@@ -130,6 +130,11 @@ class Spline {
   virtual void translate(const blender::float3 &translation);
   virtual void transform(const blender::float4x4 &matrix);
 
+  /**
+   * Change the direction of the spline (switch the start and end) without changing its shape.
+   */
+  void reverse();
+
   /**
    * Mark all caches for re-computation. This must be called after any operation that would
    * change the generated positions, tangents, normals, mapping, etc. of the evaluated points.
@@ -210,6 +215,7 @@ class Spline {
   virtual void correct_end_tangents() const = 0;
   virtual void copy_settings(Spline &dst) const = 0;
   virtual void copy_data(Spline &dst) const = 0;
+  virtual void reverse_impl() = 0;
 };
 
 /**
@@ -353,6 +359,9 @@ class BezierSpline final : public Spline {
   void correct_end_tangents() const final;
   void copy_settings(Spline &dst) const final;
   void copy_data(Spline &dst) const final;
+
+ protected:
+  void reverse_impl() override;
 };
 
 /**
@@ -469,6 +478,7 @@ class NURBSpline final : public Spline {
   void correct_end_tangents() const final;
   void copy_settings(Spline &dst) const final;
   void copy_data(Spline &dst) const final;
+  void reverse_impl() override;
 
   void calculate_knots() const;
   blender::Span<BasisCache> calculate_basis_cache() const;
@@ -519,6 +529,7 @@ class PolySpline final : public Spline {
   void correct_end_tangents() const final;
   void copy_settings(Spline &dst) const final;
   void copy_data(Spline &dst) const final;
+  void reverse_impl() override;
 };
 
 /**
-- 
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