[Bf-blender-cvs] [df4e43d9fd7] soc-2020-io-performance: Rename get_object_deform_vert; add comments

[Ankit Meel]

Commit: df4e43d9fd7001fbccb13ad5b0b0e3f0ec7e9ed4
Author: Ankit Meel
Date:   Wed Jul 1 23:58:13 2020 +0530
Branches: soc-2020-io-performance
https://developer.blender.org/rBdf4e43d9fd7001fbccb13ad5b0b0e3f0ec7e9ed4

Rename get_object_deform_vert; add comments

`get_object_deform_vert` → `get_poly_deform_group_name`

Edit comments, and the UI tooltip of the export option.

===================================================================

M	source/blender/editors/io/io_obj.c
M	source/blender/io/wavefront_obj/intern/wavefront_obj_exporter_mesh.cc
M	source/blender/io/wavefront_obj/intern/wavefront_obj_exporter_mesh.hh
M	source/blender/io/wavefront_obj/intern/wavefront_obj_file_handler.cc

===================================================================

diff --git a/source/blender/editors/io/io_obj.c b/source/blender/editors/io/io_obj.c
index 0380cea3739..a970ace4df6 100644
--- a/source/blender/editors/io/io_obj.c
+++ b/source/blender/editors/io/io_obj.c
@@ -345,7 +345,8 @@ void WM_OT_obj_export(struct wmOperatorType *ot)
       "export_vertex_groups",
       false,
       "Export vertex groups",
-      "If checked, writes the name of the vertex group to which a face's maximum vertices belong");
+      "If checked, writes the name of the vertex group of a face. It is approximated "
+      "by choosing the vertex group with the most members among the vertices of a face");
 }
 
 static int wm_obj_import_invoke(bContext *C, wmOperator *op, const wmEvent *event)
diff --git a/source/blender/io/wavefront_obj/intern/wavefront_obj_exporter_mesh.cc b/source/blender/io/wavefront_obj/intern/wavefront_obj_exporter_mesh.cc
index 5e0ba7a729d..7d6df6c6ed4 100644
--- a/source/blender/io/wavefront_obj/intern/wavefront_obj_exporter_mesh.cc
+++ b/source/blender/io/wavefront_obj/intern/wavefront_obj_exporter_mesh.cc
@@ -265,12 +265,17 @@ void OBJMesh::calc_poly_normal_indices(Vector<uint> &r_normal_indices, uint poly
 }
 
 /**
- * Find the name of the group to which maximum number of vertices of a poly belong.
- * If no vertex belongs to any group, name is "off".
- * If there's a tie between two or more vertices, group name depends on the implementation
- * of max_element.
+ * Find the name of the vertex group with the maximum number of vertices in a poly.
+ * If no vertex belongs to any group, returned name is "off".
+ * If two or more groups have the same number of vertices (maximum), group name depends on the
+ * implementation of std::max_element.
+ * If the group corresponding to r_last_vertex_group shows up on another polygon, return nullptr so
+ * that caller can skip that group.
+ *
+ * \param r_last_vertex_group stores the index of the vertex group found in last iteration,
+ * indexing into Object->defbase.
  */
-const char *OBJMesh::get_object_deform_vert(const MPoly &mpoly, short &r_last_vertex_group)
+const char *OBJMesh::get_poly_deform_group_name(const MPoly &mpoly, short &r_last_vertex_group)
 {
   const MLoop *mloop = &_export_mesh_eval->mloop[mpoly.loopstart];
   /* Indices index into deform groups; values are the number of vertices in one deform group. */
@@ -280,9 +285,11 @@ const char *OBJMesh::get_object_deform_vert(const MPoly &mpoly, short &r_last_ve
   /* Whether at least one vertex in the polygon belongs to any group. */
   bool found_group = false;
 
+  const MDeformVert *dvert;
+  const MDeformWeight *curr_weight;
   for (uint loop_index = 0; loop_index < mpoly.totloop; loop_index++) {
-    const MDeformVert dvert = _export_mesh_eval->dvert[(mloop + loop_index)->v];
-    const MDeformWeight *curr_weight = dvert.dw;
+    dvert = &_export_mesh_eval->dvert[(mloop + loop_index)->v];
+    curr_weight = dvert->dw;
     if (curr_weight) {
       bDeformGroup *vertex_group = (bDeformGroup *)BLI_findlink(
           (ListBase *)(&_export_object_eval->defbase), curr_weight->def_nr);
@@ -304,7 +311,8 @@ const char *OBJMesh::get_object_deform_vert(const MPoly &mpoly, short &r_last_ve
   int max_idx = std::max_element(deform_group_indices.begin(), deform_group_indices.end()) -
                 deform_group_indices.begin();
   if (max_idx == r_last_vertex_group) {
-    /* No need to update the name, since it won't be printed. */
+    /* No need to update the name, r_last_vertex_group indicates that it has been written already.
+     */
     return nullptr;
   }
   r_last_vertex_group = max_idx;
diff --git a/source/blender/io/wavefront_obj/intern/wavefront_obj_exporter_mesh.hh b/source/blender/io/wavefront_obj/intern/wavefront_obj_exporter_mesh.hh
index c3ba1d08c36..d76735d4f25 100644
--- a/source/blender/io/wavefront_obj/intern/wavefront_obj_exporter_mesh.hh
+++ b/source/blender/io/wavefront_obj/intern/wavefront_obj_exporter_mesh.hh
@@ -88,13 +88,6 @@ class OBJMesh : NonMovable, NonCopyable {
   void ensure_normals();
   /** Return mat_nr-th material of the object. */
   Material *get_object_material(short mat_nr);
-  /**
-   * Find the name of the group to which maximum number of vertices of a poly belong.
-   * If no vertex belongs to any group, name is "off".
-   * If there's a tie between two or more vertices, group name depends on the implementation
-   * of max_element.
-   */
-  const char *get_object_deform_vert(const MPoly &mpoly, short &r_last_vertex_group);
 
   /* Names as they appear in the outliner. */
   const char *get_object_name();
@@ -122,6 +115,19 @@ class OBJMesh : NonMovable, NonCopyable {
    * Calculate face normal indices of all polygons.
    */
   void calc_poly_normal_indices(Vector<uint> &r_normal_indices, uint poly_indices);
+  /**
+   * Find the name of the vertex group with the maximum number of vertices in a poly.
+   * If no vertex belongs to any group, returned name is "off".
+   * If two or more groups have the same number of vertices (maximum), group name depends on the
+   * implementation of std::max_element.
+   * If the group corresponding to r_last_vertex_group shows up on another polygon, return nullptr
+   * so that caller can skip that group.
+   *
+   * \param r_last_vertex_group stores the index of the vertex group found in last iteration,
+   * indexing into Object->defbase.
+   */
+  const char *get_poly_deform_group_name(const MPoly &mpoly, short &r_last_vertex_group);
+
   /**
    * Only for curve converted to meshes: calculate vertex indices of one edge.
    */
diff --git a/source/blender/io/wavefront_obj/intern/wavefront_obj_file_handler.cc b/source/blender/io/wavefront_obj/intern/wavefront_obj_file_handler.cc
index 46f3d869417..ac185044187 100644
--- a/source/blender/io/wavefront_obj/intern/wavefront_obj_file_handler.cc
+++ b/source/blender/io/wavefront_obj/intern/wavefront_obj_file_handler.cc
@@ -217,7 +217,7 @@ void OBJWriter::write_vertex_group(OBJMesh &obj_mesh_data,
   if (!_export_params->export_vertex_groups) {
     return;
   }
-  const char *def_group_name = obj_mesh_data.get_object_deform_vert(mpoly, last_face_vertex_group);
+  const char *def_group_name = obj_mesh_data.get_poly_deform_group_name(mpoly, last_face_vertex_group);
   if (!def_group_name) {
     /* Don't write the name of the group again. If set once, the group name changes only when a new
      * one is encountered. */