Editmesh: Add option to tear boundary vertices when dissolving

3 files changed, 39 insertions, 4 deletions

diff --git a/source/blender/bmesh/intern/bmesh_opdefines.c b/source/blender/bmesh/intern/bmesh_opdefines.c
index b9da7618df8..7dc46cf0678 100644
--- a/source/blender/bmesh/intern/bmesh_opdefines.c
+++ b/source/blender/bmesh/intern/bmesh_opdefines.c
@@ -956,6 +956,7 @@ static BMOpDefine bmo_dissolve_verts_def = {
 	/* slots_in */
 	{{"verts", BMO_OP_SLOT_ELEMENT_BUF, {BM_VERT}},
 	 {"use_face_split", BMO_OP_SLOT_BOOL},
+	 {"use_boundary_tear", BMO_OP_SLOT_BOOL},
 	 {{'\0'}},
 	},
 	{{{'\0'}}},  /* no output */
diff --git a/source/blender/bmesh/operators/bmo_dissolve.c b/source/blender/bmesh/operators/bmo_dissolve.c
index 209ca30ddc3..84d3cda4866 100644
--- a/source/blender/bmesh/operators/bmo_dissolve.c
+++ b/source/blender/bmesh/operators/bmo_dissolve.c
@@ -51,6 +51,7 @@
 #define VERT_MARK_PAIR 4
 #define VERT_TAG    2
 #define VERT_ISGC   8
+#define VERT_MARK_TEAR 16
 
 
 
@@ -85,7 +86,7 @@ static bool UNUSED_FUNCTION(check_hole_in_region) (BMesh *bm, BMFace *f)
 	return true;
 }
 
-static void bm_face_split(BMesh *bm, const short oflag)
+static void bm_face_split(BMesh *bm, const short oflag, bool use_edge_delete)
 {
 	BMIter iter;
 	BMVert *v;
@@ -104,6 +105,12 @@ static void bm_face_split(BMesh *bm, const short oflag)
 						}
 					}
 				}
+				/* remove surrounding edges & faces */
+				if (use_edge_delete) {
+					while (v->e) {
+						BM_edge_kill(bm, v->e);
+					}
+				}
 			}
 		}
 	}
@@ -268,7 +275,7 @@ void bmo_dissolve_edges_exec(BMesh *bm, BMOperator *op)
 			}
 		}
 
-		bm_face_split(bm, VERT_TAG);
+		bm_face_split(bm, VERT_TAG, false);
 	}
 
 	if (use_verts) {
@@ -345,13 +352,30 @@ void bmo_dissolve_verts_exec(BMesh *bm, BMOperator *op)
 	BMFace *act_face = bm->act_face;
 
 	const bool use_face_split = BMO_slot_bool_get(op->slots_in, "use_face_split");
+	const bool use_boundary_tear = BMO_slot_bool_get(op->slots_in, "use_boundary_tear");
 
 	BMO_ITER (v, &oiter, op->slots_in, "verts", BM_VERT) {
 		BMO_elem_flag_enable(bm, v, VERT_MARK | VERT_ISGC);
 	}
 
 	if (use_face_split) {
-		bm_face_split(bm, VERT_MARK);
+		bm_face_split(bm, VERT_MARK, false);
+	}
+
+	if (use_boundary_tear) {
+		BMO_ITER (v, &oiter, op->slots_in, "verts", BM_VERT) {
+			if (!BM_vert_is_edge_pair(v)) {
+				BM_ITER_ELEM (e, &iter, v, BM_EDGES_OF_VERT) {
+					if (BM_edge_is_boundary(e)) {
+						BMO_elem_flag_enable(bm, v, VERT_MARK_TEAR);
+						break;
+					}
+				}
+			}
+		}
+		if (!use_face_split) {
+			bm_face_split(bm, VERT_MARK_TEAR, true);
+		}
 	}
 
 	BMO_ITER (v, &oiter, op->slots_in, "verts", BM_VERT) {
diff --git a/source/blender/editors/mesh/editmesh_tools.c b/source/blender/editors/mesh/editmesh_tools.c
index 233de9cbf8d..2ee555509f5 100644
--- a/source/blender/editors/mesh/editmesh_tools.c
+++ b/source/blender/editors/mesh/editmesh_tools.c
@@ -3479,6 +3479,11 @@ static void edbm_dissolve_prop__use_face_split(wmOperatorType *ot)
 	RNA_def_boolean(ot->srna, "use_face_split", 0, "Face Split",
 	                "Split off face corners to maintain surrounding geometry");
 }
+static void edbm_dissolve_prop__use_boundary_tear(wmOperatorType *ot)
+{
+	RNA_def_boolean(ot->srna, "use_boundary_tear", 0, "Tear Boundary",
+	                "Split off face corners instead of merging faces");
+}
 
 static int edbm_dissolve_verts_exec(bContext *C, wmOperator *op)
 {
@@ -3486,8 +3491,11 @@ static int edbm_dissolve_verts_exec(bContext *C, wmOperator *op)
 	BMEditMesh *em = BKE_editmesh_from_object(obedit);
 
 	const bool use_face_split = RNA_boolean_get(op->ptr, "use_face_split");
+	const bool use_boundary_tear = RNA_boolean_get(op->ptr, "use_boundary_tear");
 
-	if (!EDBM_op_callf(em, op, "dissolve_verts verts=%hv use_face_split=%b", BM_ELEM_SELECT, use_face_split))
+	if (!EDBM_op_callf(em, op,
+	                   "dissolve_verts verts=%hv use_face_split=%b use_boundary_tear=%b",
+	                   BM_ELEM_SELECT, use_face_split, use_boundary_tear))
 		return OPERATOR_CANCELLED;
 
 	EDBM_update_generic(em, true, true);
@@ -3510,6 +3518,7 @@ void MESH_OT_dissolve_verts(wmOperatorType *ot)
 	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
 	edbm_dissolve_prop__use_face_split(ot);
+	edbm_dissolve_prop__use_boundary_tear(ot);
 }
 
 static int edbm_dissolve_edges_exec(bContext *C, wmOperator *op)
@@ -3621,6 +3630,7 @@ void MESH_OT_dissolve_mode(wmOperatorType *ot)
 
 	edbm_dissolve_prop__use_verts(ot);
 	edbm_dissolve_prop__use_face_split(ot);
+	edbm_dissolve_prop__use_boundary_tear(ot);
 }
 
 static int edbm_dissolve_limited_exec(bContext *C, wmOperator *op)