new bmesh operator bisect_plane, cuts a mesh in half, takes a user defined plane as an argument, handles concave ngons which need multiple cuts.

1 files changed, 100 insertions, 0 deletions

diff --git a/source/blender/bmesh/operators/bmo_bisect_plane.c b/source/blender/bmesh/operators/bmo_bisect_plane.c
new file mode 100644
index 00000000000..a4103bfec41
--- /dev/null
+++ b/source/blender/bmesh/operators/bmo_bisect_plane.c
@@ -0,0 +1,100 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Contributor(s):
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/bmesh/operators/bmo_bisect_plane.c
+ *  \ingroup bmesh
+ *
+ * Wrapper around #BM_mesh_bisect_plane
+ */
+
+#include "BLI_utildefines.h"
+#include "BLI_math.h"
+
+#include "bmesh.h"
+
+#include "intern/bmesh_operators_private.h" /* own include */
+
+#define ELE_NEW 1
+#define ELE_INPUT 2
+
+void bmo_bisect_plane_exec(BMesh *bm, BMOperator *op)
+{
+	const float dist  = BMO_slot_float_get(op->slots_in, "dist");
+	const bool clear_outer = BMO_slot_bool_get(op->slots_in,  "clear_outer");
+	const bool clear_inner = BMO_slot_bool_get(op->slots_in,  "clear_inner");
+
+	float plane_co[3];
+	float plane_no[3];
+	float plane[4];
+
+	BMO_slot_vec_get(op->slots_in, "plane_co", plane_co);
+	BMO_slot_vec_get(op->slots_in, "plane_no", plane_no);
+
+	if (is_zero_v3(plane_no)) {
+		BMO_error_raise(bm, op, BMERR_MESH_ERROR, "Zero normal given");
+		return;
+	}
+
+	plane_from_point_normal_v3(plane, plane_co, plane_no);
+
+	/* tag geometry to bisect */
+	BM_mesh_elem_hflag_disable_all(bm, BM_EDGE | BM_FACE, BM_ELEM_TAG, false);
+	BMO_slot_buffer_hflag_enable(bm, op->slots_in, "geom", BM_EDGE | BM_FACE, BM_ELEM_TAG, false);
+
+	BMO_slot_buffer_flag_enable(bm, op->slots_in, "geom", BM_ALL_NOLOOP, ELE_INPUT);
+
+
+	BM_mesh_bisect_plane(bm, plane, true,
+	                     ELE_NEW, dist);
+
+
+	if (clear_outer || clear_inner) {
+		BMOIter siter;
+		BMVert *v;
+		float plane_alt[4];
+
+		copy_v3_v3(plane_alt, plane);
+
+		if (clear_outer) {
+			plane_alt[3] = plane[3] - dist;
+
+			BMO_ITER (v, &siter, op->slots_in, "geom", BM_VERT) {
+				if (plane_point_side_v3(plane_alt, v->co) > 0.0f) {
+					BM_vert_kill(bm, v);
+				}
+			}
+		}
+
+		if (clear_inner) {
+			plane_alt[3] = plane[3] + dist;
+
+			BMO_ITER (v, &siter, op->slots_in, "geom", BM_VERT) {
+				if (plane_point_side_v3(plane_alt, v->co) < 0.0f) {
+					BM_vert_kill(bm, v);
+				}
+			}
+		}
+	}
+
+	BMO_slot_buffer_from_enabled_flag(bm, op, op->slots_out, "geom.out", BM_ALL_NOLOOP, ELE_NEW | ELE_INPUT);
+	BMO_slot_buffer_from_enabled_flag(bm, op, op->slots_out, "geom_cut.out", BM_VERT | BM_EDGE, ELE_NEW);
+}