Fix #30290: Shape Keys not working as expected

New method of vertex shapekey propagation didn't restored coordinates in
me->mvert array which lead to unwanted deformation of basis mesh and
lead to issues like described in the report.

1 files changed, 10 insertions, 0 deletions

diff --git a/source/blender/bmesh/operators/bmo_mesh_conv.c b/source/blender/bmesh/operators/bmo_mesh_conv.c
index 7b929042ea9..ce46ae7493d 100644
--- a/source/blender/bmesh/operators/bmo_mesh_conv.c
+++ b/source/blender/bmesh/operators/bmo_mesh_conv.c
@@ -759,6 +759,7 @@ void bmesh_to_mesh_exec(BMesh *bm, BMOperator *op)
 					currkey->data = fp = MEM_mallocN(sizeof(float) * 3 * bm->totvert, "shape key data");
 					currkey->totelem = bm->totvert;
 
+					mvert = me->mvert;
 					BM_ITER(eve, &iter, bm, BM_VERTS_OF_MESH, NULL) {
 						co = (currkey == actkey) ?
 						            eve->co :
@@ -771,6 +772,15 @@ void bmesh_to_mesh_exec(BMesh *bm, BMOperator *op)
 							add_v3_v3(fp, *ofs_pt++);
 						}
 
+						if (currkey == actkey && oldverts) {
+							keyi = CustomData_bmesh_get(&bm->vdata, eve->head.data, CD_SHAPE_KEYINDEX);
+
+							if (*keyi >= 0 && *keyi < currkey->totelem) // valid old vertex
+								copy_v3_v3(mvert->co, oldverts[*keyi].co);
+
+							mvert++;
+						}
+
 						fp += 3;
 					}
 					break;