source/blender/blenkernel/BKE_curves.hh

@@ -25,6 +25,8 @@
 #include "BKE_attribute_math.hh"
 #include "BKE_curves.h"
 
+#include "DNA_meshdata_types.h"
+
 namespace blender::bke {
 
 namespace curves::nurbs {
@@ -257,6 +259,13 @@ class CurvesGeometry : public ::CurvesGeometry {
   Span<float2> surface_uv_coords() const;
   MutableSpan<float2> surface_uv_coords_for_write();
 
+  /**
+   * Vertex group data, encoded as an array of indices and weights for every vertex.
+   * \warning: May be empty.
+   */
+  Span<MDeformVert> deform_verts() const;
+  MutableSpan<MDeformVert> deform_verts_for_write();
+
   /**
    * The largest and smallest position values of evaluated points.
    */

source/blender/blenkernel/intern/curves_geometry.cc

@@ -458,6 +458,28 @@ MutableSpan<float2> CurvesGeometry::surface_uv_coords_for_write()
   return get_mutable_attribute<float2>(*this, ATTR_DOMAIN_CURVE, ATTR_SURFACE_UV_COORDINATE);
 }
 
+Span<MDeformVert> CurvesGeometry::deform_verts() const
+{
+  const MDeformVert *dverts = (const MDeformVert *)CustomData_get_layer(&this->point_data,
+                                                                        CD_MDEFORMVERT);
+  if (dverts == nullptr) {
+    return {};
+  }
+  return {dverts, this->point_num};
+}
+
+MutableSpan<MDeformVert> CurvesGeometry::deform_verts_for_write()
+{
+  MDeformVert *dvert = (MDeformVert *)CustomData_get_layer_for_write(
+      &this->point_data, CD_MDEFORMVERT, this->point_num);
+  if (dvert != nullptr) {
+    return {dvert, this->point_num};
+  }
+  return {(MDeformVert *)CustomData_add_layer(
+              &this->point_data, CD_MDEFORMVERT, CD_SET_DEFAULT, this->point_num),
+          this->point_num};
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */

source/blender/makesdna/DNA_curves_types.h

@@ -10,7 +10,9 @@
 
 #include "DNA_ID.h"
 #include "DNA_customdata_types.h"
+#include "DNA_object_types.h"
 
+#include "BLI_listbase.h"
 #include "BLI_utildefines.h"
 
 #ifdef __cplusplus
@@ -132,6 +134,14 @@ typedef struct CurvesGeometry {
    */
   int curve_num;
 
+  /**
+   * List of vertex group (#bDeformGroup) names and flags only.
+   */
+  ListBase vertex_group_names;
+  /** The active index in the #vertex_group_names list. */
+  int vertex_group_active_index;
+  char _pad[4];
+
   /**
    * Runtime data for curves, stored as a pointer to allow defining this as a C++ class.
    */