From 0ffde4fae3bd6a62302d829d319955b012a9b73a Mon Sep 17 00:00:00 2001
From: Campbell Barton <ideasman42@gmail.com>
Date: Tue, 7 May 2013 00:00:32 +0000
Subject: expose bmesh volume calculation to python api (use for print toolbox
 addon).

---
 source/blender/bmesh/intern/bmesh_queries.c        |  8 ++++--
 source/blender/bmesh/intern/bmesh_queries.h        |  2 +-
 .../blender/bmesh/operators/bmo_smooth_laplacian.c |  4 +--
 source/blender/python/bmesh/bmesh_py_types.c       | 32 ++++++++++++++++++++++
 4 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/source/blender/bmesh/intern/bmesh_queries.c b/source/blender/bmesh/intern/bmesh_queries.c
index a4ddc0cbba4..8a1d513a8fc 100644
--- a/source/blender/bmesh/intern/bmesh_queries.c
+++ b/source/blender/bmesh/intern/bmesh_queries.c
@@ -1720,7 +1720,7 @@ static void bm_mesh_calc_volume_face(BMFace *f, float *r_vol)
 		*r_vol += (1.0f / 6.0f) * dot_v3v3(p1, cross);
 	}
 }
-float BM_mesh_calc_volume(BMesh *bm)
+float BM_mesh_calc_volume(BMesh *bm, bool is_signed)
 {
 	/* warning, calls own tessellation function, may be slow */
 	float vol = 0.0f;
@@ -1731,5 +1731,9 @@ float BM_mesh_calc_volume(BMesh *bm)
 		bm_mesh_calc_volume_face(f, &vol);
 	}
 
-	return fabsf(vol);
+	if (is_signed == false) {
+		vol = fabsf(vol);
+	}
+
+	return vol;
 }
diff --git a/source/blender/bmesh/intern/bmesh_queries.h b/source/blender/bmesh/intern/bmesh_queries.h
index 3d3e1a3d9d9..6b1bfca2d80 100644
--- a/source/blender/bmesh/intern/bmesh_queries.h
+++ b/source/blender/bmesh/intern/bmesh_queries.h
@@ -113,6 +113,6 @@ bool BM_edge_is_any_vert_flag_test(BMEdge *e, const char hflag);
 bool BM_face_is_any_vert_flag_test(BMFace *f, const char hflag);
 bool BM_face_is_any_edge_flag_test(BMFace *f, const char hflag);
 
-float BM_mesh_calc_volume(BMesh *bm);
+float BM_mesh_calc_volume(BMesh *bm, bool is_signed);
 
 #endif /* __BMESH_QUERIES_H__ */
diff --git a/source/blender/bmesh/operators/bmo_smooth_laplacian.c b/source/blender/bmesh/operators/bmo_smooth_laplacian.c
index 12368d1aeda..91a52cdabef 100644
--- a/source/blender/bmesh/operators/bmo_smooth_laplacian.c
+++ b/source/blender/bmesh/operators/bmo_smooth_laplacian.c
@@ -464,7 +464,7 @@ static void validate_solution(LaplacianSystem *sys, int usex, int usey, int usez
 	}
 
 	if (preserve_volume) {
-		vini = BM_mesh_calc_volume(sys->bm);
+		vini = BM_mesh_calc_volume(sys->bm, false);
 	}
 	BMO_ITER (v, &siter, sys->op->slots_in, "verts", BM_VERT) {
 		m_vertex_id = BM_elem_index_get(v);
@@ -481,7 +481,7 @@ static void validate_solution(LaplacianSystem *sys, int usex, int usey, int usez
 		}
 	}
 	if (preserve_volume) {
-		vend = BM_mesh_calc_volume(sys->bm);
+		vend = BM_mesh_calc_volume(sys->bm, false);
 		volume_preservation(sys->op, vini, vend, usex, usey, usez);
 	}
 
diff --git a/source/blender/python/bmesh/bmesh_py_types.c b/source/blender/python/bmesh/bmesh_py_types.c
index 55a6f3c41c4..23837404b31 100644
--- a/source/blender/python/bmesh/bmesh_py_types.c
+++ b/source/blender/python/bmesh/bmesh_py_types.c
@@ -1171,6 +1171,35 @@ static PyObject *bpy_bmesh_transform(BPy_BMElem *self, PyObject *args, PyObject
 	Py_RETURN_NONE;
 }
 
+PyDoc_STRVAR(bpy_bmesh_calc_volume_doc,
+".. method:: calc_volume(signed=False)\n"
+"\n"
+"   Calculate mesh volume based on face normals.\n"
+"\n"
+"   :arg signed: when signed is true, negative values may be returned.\n"
+"   :type signed: bool\n"
+"   :return: The volume of the mesh.\n"
+"   :rtype: float\n"
+);
+static PyObject *bpy_bmesh_calc_volume(BPy_BMElem *self, PyObject *args, PyObject *kw)
+{
+	static const char *kwlist[] = {"signed", NULL};
+	PyObject *is_signed = Py_False;
+
+	BPY_BM_CHECK_OBJ(self);
+
+	if (!PyArg_ParseTupleAndKeywords(args, kw,
+	                                 "|O!:calc_volume",
+	                                 (char **)kwlist,
+	                                 &PyBool_Type, &is_signed))
+	{
+		return NULL;
+	}
+	else {
+		return PyFloat_FromDouble(BM_mesh_calc_volume(self->bm, is_signed != Py_False));
+	}
+}
+
 
 /* Elem
  * ---- */
@@ -2454,6 +2483,9 @@ static struct PyMethodDef bpy_bmesh_methods[] = {
 	{"select_flush", (PyCFunction)bpy_bmesh_select_flush, METH_O, bpy_bmesh_select_flush_doc},
 	{"normal_update", (PyCFunction)bpy_bmesh_normal_update, METH_NOARGS, bpy_bmesh_normal_update_doc},
 	{"transform", (PyCFunction)bpy_bmesh_transform, METH_VARARGS | METH_KEYWORDS, bpy_bmesh_transform_doc},
+
+	/* calculations */
+	{"calc_volume", (PyCFunction)bpy_bmesh_calc_volume, METH_VARARGS | METH_KEYWORDS, bpy_bmesh_calc_volume_doc},
 	{NULL, NULL, 0, NULL}
 };
 
-- 
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