Fix T92314: Auto naming of the Vertex Group doesn't work for Grease

Pencil

Not naming the auto-generated vertexgroup after the selected bone was
just confusing (since the group would not have an effect), so now use
similar code that is used for meshes for greasepencil as well.

Maniphest Tasks: T92314

Differential Revision: https://developer.blender.org/D12906

1 files changed, 19 insertions, 1 deletions

diff --git a/source/blender/editors/gpencil/gpencil_weight_paint.c b/source/blender/editors/gpencil/gpencil_weight_paint.c
index a3e5ece5862..9a312c255b1 100644
--- a/source/blender/editors/gpencil/gpencil_weight_paint.c
+++ b/source/blender/editors/gpencil/gpencil_weight_paint.c
@@ -29,15 +29,18 @@
 
 #include "BLT_translation.h"
 
+#include "DNA_armature_types.h"
 #include "DNA_brush_types.h"
 #include "DNA_gpencil_types.h"
 
+#include "BKE_action.h"
 #include "BKE_brush.h"
 #include "BKE_colortools.h"
 #include "BKE_context.h"
 #include "BKE_deform.h"
 #include "BKE_gpencil.h"
 #include "BKE_main.h"
+#include "BKE_modifier.h"
 #include "BKE_object_deform.h"
 #include "BKE_report.h"
 #include "DNA_meshdata_types.h"
@@ -246,7 +249,22 @@ static bool brush_draw_apply(tGP_BrushWeightpaintData *gso,
   /* need a vertex group */
   if (gso->vrgroup == -1) {
     if (gso->object) {
-      BKE_object_defgroup_add(gso->object);
+      Object *ob_armature = BKE_modifiers_is_deformed_by_armature(gso->object);
+      if ((ob_armature != NULL)) {
+        Bone *actbone = ((bArmature *)ob_armature->data)->act_bone;
+        if (actbone != NULL) {
+          bPoseChannel *pchan = BKE_pose_channel_find_name(ob_armature->pose, actbone->name);
+          if (pchan != NULL) {
+            bDeformGroup *dg = BKE_object_defgroup_find_name(gso->object, pchan->name);
+            if (dg == NULL) {
+              dg = BKE_object_defgroup_add_name(gso->object, pchan->name);
+            }
+          }
+        }
+      }
+      else {
+        BKE_object_defgroup_add(gso->object);
+      }
       DEG_relations_tag_update(gso->bmain);
       gso->vrgroup = 0;
     }