1 files changed, 46 insertions, 0 deletions

diff --git a/source/blender/bmesh/intern/bmesh_interp.c b/source/blender/bmesh/intern/bmesh_interp.c
index 5149a5436a2..c774880332b 100644
--- a/source/blender/bmesh/intern/bmesh_interp.c
+++ b/source/blender/bmesh/intern/bmesh_interp.c
@@ -853,6 +853,52 @@ void BM_data_layer_free_n(BMesh *bm, CustomData *data, int type, int n)
 	if (olddata.layers) MEM_freeN(olddata.layers);
 }
 
+void BM_data_layer_copy(BMesh *bm, CustomData *data, int type, int src_n, int dst_n)
+{
+	BMIter iter;
+
+	if (&bm->vdata == data) {
+		BMVert *eve;
+
+		BM_ITER_MESH (eve, &iter, bm, BM_VERTS_OF_MESH) {
+			void *ptr = CustomData_bmesh_get_n(data, eve->head.data, type, dst_n);
+			CustomData_bmesh_set_n(data, eve->head.data, type, src_n, ptr);
+		}
+	}
+	else if (&bm->edata == data) {
+		BMEdge *eed;
+
+		BM_ITER_MESH (eed, &iter, bm, BM_EDGES_OF_MESH) {
+			void *ptr = CustomData_bmesh_get_n(data, eed->head.data, type, dst_n);
+			CustomData_bmesh_set_n(data, eed->head.data, type, src_n, ptr);
+		}
+	}
+	else if (&bm->pdata == data) {
+		BMFace *efa;
+
+		BM_ITER_MESH (efa, &iter, bm, BM_FACES_OF_MESH) {
+			void *ptr = CustomData_bmesh_get_n(data, efa->head.data, type, dst_n);
+			CustomData_bmesh_set_n(data, efa->head.data, type, src_n, ptr);
+		}
+	}
+	else if (&bm->ldata == data) {
+		BMIter liter;
+		BMFace *efa;
+		BMLoop *l;
+
+		BM_ITER_MESH (efa, &iter, bm, BM_FACES_OF_MESH) {
+			BM_ITER_ELEM (l, &liter, efa, BM_LOOPS_OF_FACE) {
+				void *ptr = CustomData_bmesh_get_n(data, l->head.data, type, dst_n);
+				CustomData_bmesh_set_n(data, l->head.data, type, src_n, ptr);
+			}
+		}
+	}
+	else {
+		/* should never reach this! */
+		BLI_assert(0);
+	}
+}
+
 float BM_elem_float_data_get(CustomData *cd, void *element, int type)
 {
 	float *f = CustomData_bmesh_get(cd, ((BMHeader *)element)->data, type);