Cleanup: Move public docs to BKE_spline.hh header

1 files changed, 99 insertions, 2 deletions

diff --git a/source/blender/blenkernel/BKE_spline.hh b/source/blender/blenkernel/BKE_spline.hh
index 67eaa7c12c9..b8b18f0b50a 100644
--- a/source/blender/blenkernel/BKE_spline.hh
+++ b/source/blender/blenkernel/BKE_spline.hh
@@ -286,6 +286,9 @@ class BezierSpline final : public Spline {
   int resolution() const;
   void set_resolution(const int value);
 
+  /**
+   * \warning Call #reallocate on the spline's attributes after adding all points.
+   */
   void add_point(const blender::float3 position,
                  const HandleType handle_type_left,
                  const blender::float3 handle_position_left,
@@ -321,12 +324,24 @@ class BezierSpline final : public Spline {
    * uninitialized memory while auto-generating handles.
    */
   blender::MutableSpan<blender::float3> handle_positions_right(bool write_only = false);
+  /**
+   * Recalculate all #Auto and #Vector handles with positions automatically
+   * derived from the neighboring control points.
+   */
   void ensure_auto_handles() const;
 
   void translate(const blender::float3 &translation) override;
   void transform(const blender::float4x4 &matrix) override;
 
+  /**
+   * Set positions for the right handle of the control point, ensuring that
+   * aligned handles stay aligned. Has no effect for auto and vector type handles.
+   */
   void set_handle_position_right(const int index, const blender::float3 &value);
+  /**
+   * Set positions for the left handle of the control point, ensuring that
+   * aligned handles stay aligned. Has no effect for auto and vector type handles.
+   */
   void set_handle_position_left(const int index, const blender::float3 &value);
 
   bool point_is_sharp(const int index) const;
@@ -334,7 +349,22 @@ class BezierSpline final : public Spline {
   void mark_cache_invalid() final;
   int evaluated_points_size() const final;
 
+  /**
+   * Returns access to a cache of offsets into the evaluated point array for each control point.
+   * While most control point edges generate the number of edges specified by the resolution,
+   * vector segments only generate one edge.
+   *
+   * \note The length of the result is one greater than the number of points, so that the last item
+   * is the total number of evaluated points. This is useful to avoid recalculating the size of the
+   * last segment everywhere.
+   */
   blender::Span<int> control_point_offsets() const;
+  /**
+   * Returns non-owning access to an array of values containing the information necessary to
+   * interpolate values from the original control points to evaluated points. The control point
+   * index is the integer part of each value, and the factor used for interpolating to the next
+   * control point is the remaining factional part.
+   */
   blender::Span<float> evaluated_mappings() const;
   blender::Span<blender::float3> evaluated_positions() const final;
   struct InterpolationData {
@@ -346,6 +376,11 @@ class BezierSpline final : public Spline {
      */
     float factor;
   };
+  /**
+   * Convert the data encoded in #evaulated_mappings into its parts-- the information necessary
+   * to interpolate data from control points to evaluated points between them. The next control
+   * point index result will not overflow the size of the control point vectors.
+   */
   InterpolationData interpolation_data_from_index_factor(const float index_factor) const;
 
   virtual blender::fn::GVArray interpolate_to_evaluated(
@@ -354,6 +389,9 @@ class BezierSpline final : public Spline {
   void evaluate_segment(const int index,
                         const int next_index,
                         blender::MutableSpan<blender::float3> positions) const;
+  /**
+   * \warning This functional assumes that the spline has more than one point.
+   */
   bool segment_is_vector(const int start_index) const;
 
   /** See comment and diagram for #calculate_segment_insertion. */
@@ -364,6 +402,25 @@ class BezierSpline final : public Spline {
     blender::float3 right_handle;
     blender::float3 handle_next;
   };
+  /**
+   * De Casteljau Bezier subdivision.
+   * \param index: The index of the segment's start control point.
+   * \param next_index: The index of the control point at the end of the segment. Could be 0,
+   * if the spline is cyclic.
+   * \param parameter: The factor along the segment, between 0 and 1. Note that this is used
+   * directly by the calculation, it doesn't correspond to a portion of the evaluated length.
+   *
+   * <pre>
+   *           handle_prev         handle_next
+   *                x----------------x
+   *               /                  \
+   *              /      x---O---x     \
+   *             /        result        \
+   *            /                        \
+   *           O                          O
+   *       point_prev                  point_next
+   * </pre>
+   */
   InsertResult calculate_segment_insertion(const int index,
                                            const int next_index,
                                            const float parameter);
@@ -460,6 +517,9 @@ class NURBSpline final : public Spline {
   uint8_t order() const;
   void set_order(const uint8_t value);
 
+  /**
+   * \warning Call #reallocate on the spline's attributes after adding all points.
+   */
   void add_point(const blender::float3 position,
                  const float radius,
                  const float tilt,
@@ -521,6 +581,9 @@ class PolySpline final : public Spline {
 
   int size() const final;
 
+  /**
+   * \warning Call #reallocate on the spline's attributes after adding all points.
+   */
   void add_point(const blender::float3 position, const float radius, const float tilt);
 
   void resize(const int size) final;
@@ -546,8 +609,12 @@ class PolySpline final : public Spline {
 };
 
 /**
- * A #CurveEval corresponds to the #Curve object data. The name is different for clarity, since
- * more of the data is stored in the splines, but also just to be different than the name in DNA.
+ * A collection of #Spline objects with the same attribute types and names. Most data and
+ * functionality is in splines, but this contains some helpers for working with them as a group.
+ *
+ * \note A #CurveEval corresponds to the #Curve object data. The name is different for clarity,
+ * since more of the data is stored in the splines, but also just to be different than the name in
+ * DNA.
  */
 struct CurveEval {
  private:
@@ -566,9 +633,18 @@ struct CurveEval {
 
   blender::Span<SplinePtr> splines() const;
   blender::MutableSpan<SplinePtr> splines();
+  /**
+   * \return True if the curve contains a spline with the given type.
+   *
+   * \note If you are looping over all of the splines in the same scope anyway,
+   * it's better to avoid calling this function, in case there are many splines.
+   */
   bool has_spline_with_type(const Spline::Type type) const;
 
   void resize(const int size);
+  /**
+   * \warning Call #reallocate on the spline's attributes after adding all splines.
+   */
   void add_spline(SplinePtr spline);
   void remove_splines(blender::IndexMask mask);
 
@@ -576,8 +652,22 @@ struct CurveEval {
   void transform(const blender::float4x4 &matrix);
   void bounds_min_max(blender::float3 &min, blender::float3 &max, const bool use_evaluated) const;
 
+  /**
+   * Return the start indices for each of the curve spline's control points, if they were part
+   * of a flattened array. This can be used to facilitate parallelism by avoiding the need to
+   * accumulate an offset while doing more complex calculations.
+   *
+   * \note The result is one longer than the spline count; the last element is the total size.
+   */
   blender::Array<int> control_point_offsets() const;
+  /**
+   * Exactly like #control_point_offsets, but uses the number of evaluated points instead.
+   */
   blender::Array<int> evaluated_point_offsets() const;
+  /**
+   * Return the accumulated length at the start of every spline in the curve.
+   * \note The result is one longer than the spline count; the last element is the total length.
+   */
   blender::Array<float> accumulated_spline_lengths() const;
 
   float total_length() const;
@@ -585,6 +675,13 @@ struct CurveEval {
 
   void mark_cache_invalid();
 
+  /**
+   * Check the invariants that curve control point attributes should always uphold, necessary
+   * because attributes are stored on splines rather than in a flat array on the curve:
+   *  - The same set of attributes exists on every spline.
+   *  - Attributes with the same name have the same type on every spline.
+   *  - Attributes are in the same order on every spline.
+   */
   void assert_valid_point_attributes() const;
 };