bmesh edge dissolve: add option use_face_split (matching vertex dissolve option),

useful to avoid odd shaped ngons surrounding dissolved edges.

3 files changed, 58 insertions, 18 deletions

diff --git a/source/blender/bmesh/intern/bmesh_opdefines.c b/source/blender/bmesh/intern/bmesh_opdefines.c
index 012cbccacc7..3958aa0ab7d 100644
--- a/source/blender/bmesh/intern/bmesh_opdefines.c
+++ b/source/blender/bmesh/intern/bmesh_opdefines.c
@@ -884,6 +884,7 @@ static BMOpDefine bmo_dissolve_edges_def = {
 	/* slots_in */
 	{{"edges", BMO_OP_SLOT_ELEMENT_BUF, {BM_EDGE}},
 	 {"use_verts", BMO_OP_SLOT_BOOL},  /* dissolve verts left between only 2 edges. */
+	 {"use_face_split", BMO_OP_SLOT_BOOL},
 	 {{'\0'}},
 	},
 	/* slots_out */
diff --git a/source/blender/bmesh/operators/bmo_dissolve.c b/source/blender/bmesh/operators/bmo_dissolve.c
index 0f72a016e2f..cca88a9eb47 100644
--- a/source/blender/bmesh/operators/bmo_dissolve.c
+++ b/source/blender/bmesh/operators/bmo_dissolve.c
@@ -39,8 +39,10 @@
 #define FACE_ORIG   2
 #define FACE_NEW    4
 #define EDGE_MARK   1
+#define EDGE_TAG    2
 
 #define VERT_MARK   1
+#define VERT_TAG    2
 
 static bool UNUSED_FUNCTION(check_hole_in_region) (BMesh *bm, BMFace *f)
 {
@@ -73,6 +75,30 @@ static bool UNUSED_FUNCTION(check_hole_in_region) (BMesh *bm, BMFace *f)
 	return true;
 }
 
+static void bm_face_split(BMesh *bm, const short oflag)
+{
+	BMIter iter;
+	BMVert *v;
+
+	BMIter liter;
+	BM_ITER_MESH (v, &iter, bm, BM_VERTS_OF_MESH) {
+		if (BMO_elem_flag_test(bm, v, oflag)) {
+			if (BM_vert_edge_count(v) > 2) {
+				BMLoop *l;
+				BM_ITER_ELEM (l, &liter, v, BM_LOOPS_OF_VERT) {
+					if (l->f->len > 3) {
+						if (BMO_elem_flag_test(bm, l->next->v, oflag) == 0 &&
+						    BMO_elem_flag_test(bm, l->prev->v, oflag) == 0)
+						{
+							BM_face_split(bm, l->f, l->next->v, l->prev->v, NULL, NULL, true);
+						}
+					}
+				}
+			}
+		}
+	}
+}
+
 void bmo_dissolve_faces_exec(BMesh *bm, BMOperator *op)
 {
 	BMOIter oiter;
@@ -272,6 +298,28 @@ void bmo_dissolve_edges_exec(BMesh *bm, BMOperator *op)
 	BMVert *v;
 
 	const bool use_verts = BMO_slot_bool_get(op->slots_in, "use_verts");
+	const bool use_face_split = BMO_slot_bool_get(op->slots_in, "use_face_split");
+
+	if (use_face_split) {
+		BMO_slot_buffer_flag_enable(bm, op->slots_in, "edges", BM_EDGE, EDGE_TAG);
+
+		BM_ITER_MESH (v, &viter, bm, BM_VERTS_OF_MESH) {
+			BMIter iter;
+			int untag_count = 0;
+			BM_ITER_ELEM(e, &iter, v, BM_EDGES_OF_VERT) {
+				if (!BMO_elem_flag_test(bm, e, EDGE_TAG)) {
+					untag_count++;
+				}
+			}
+
+			/* check that we have 2 edges remaining after dissolve */
+			if (untag_count <= 2) {
+				BMO_elem_flag_enable(bm, v, VERT_TAG);
+			}
+		}
+
+		bm_face_split(bm, VERT_TAG);
+	}
 
 	if (use_verts) {
 		BM_ITER_MESH (v, &viter, bm, BM_VERTS_OF_MESH) {
@@ -366,23 +414,7 @@ void bmo_dissolve_verts_exec(BMesh *bm, BMOperator *op)
 	BMO_slot_buffer_flag_enable(bm, op->slots_in, "verts", BM_VERT, VERT_MARK);
 	
 	if (use_face_split) {
-		BMIter liter;
-		BM_ITER_MESH (v, &iter, bm, BM_VERTS_OF_MESH) {
-			if (BMO_elem_flag_test(bm, v, VERT_MARK)) {
-				if (BM_vert_edge_count(v) > 2) {
-					BMLoop *l;
-					BM_ITER_ELEM (l, &liter, v, BM_LOOPS_OF_VERT) {
-						if (l->f->len > 3) {
-							if (BMO_elem_flag_test(bm, l->next->v, VERT_MARK) == 0 &&
-								BMO_elem_flag_test(bm, l->prev->v, VERT_MARK) == 0)
-							{
-								BM_face_split(bm, l->f, l->next->v, l->prev->v, NULL, NULL, true);
-							}
-						}
-					}
-				}
-			}
-		}
+		bm_face_split(bm, VERT_MARK);
 	}
 
 	BM_ITER_MESH (v, &iter, bm, BM_VERTS_OF_MESH) {
diff --git a/source/blender/editors/mesh/editmesh_tools.c b/source/blender/editors/mesh/editmesh_tools.c
index 1f7690b9b42..fa29a1e2ea8 100644
--- a/source/blender/editors/mesh/editmesh_tools.c
+++ b/source/blender/editors/mesh/editmesh_tools.c
@@ -2991,9 +2991,14 @@ static int edbm_dissolve_edges_exec(bContext *C, wmOperator *op)
 	BMEditMesh *em = BKE_editmesh_from_object(obedit);
 
 	const bool use_verts = RNA_boolean_get(op->ptr, "use_verts");
+	const bool use_face_split = RNA_boolean_get(op->ptr, "use_face_split");
 
-	if (!EDBM_op_callf(em, op, "dissolve_edges edges=%he use_verts=%b", BM_ELEM_SELECT, use_verts))
+	if (!EDBM_op_callf(em, op,
+	                   "dissolve_edges edges=%he use_verts=%b use_face_split=%b",
+	                   BM_ELEM_SELECT, use_verts, use_face_split))
+	{
 		return OPERATOR_CANCELLED;
+	}
 
 	EDBM_update_generic(em, true, true);
 
@@ -3015,6 +3020,8 @@ void MESH_OT_dissolve_edges(wmOperatorType *ot)
 	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
 	RNA_def_boolean(ot->srna, "use_verts", 0, "Dissolve Verts", "Dissolve remaining vertices");
+	RNA_def_boolean(ot->srna, "use_face_split", 0, "Face Split",
+	                "Split off face corners to maintain surrounding geometry");
 }
 
 static int edbm_dissolve_faces_exec(bContext *C, wmOperator *op)