bmesh api function: BM_edge_face_tangent()

 was used by inset but make into an api function since scripts can use this too.

1 files changed, 33 insertions, 2 deletions

diff --git a/source/blender/python/bmesh/bmesh_py_types.c b/source/blender/python/bmesh/bmesh_py_types.c
index 5fcefc7533b..6b6fd8a0bd4 100644
--- a/source/blender/python/bmesh/bmesh_py_types.c
+++ b/source/blender/python/bmesh/bmesh_py_types.c
@@ -1243,6 +1243,36 @@ static PyObject *bpy_bmedge_calc_face_angle(BPy_BMEdge *self)
 	return PyFloat_FromDouble(BM_edge_face_angle(self->e));
 }
 
+PyDoc_STRVAR(bpy_bmedge_calc_tangent_doc,
+".. method:: calc_tangent(loop)\n"
+"\n"
+"   Return the tangent at this edge relative to a face (pointing inward into the face).\n"
+"   This uses the face normal for calculation.\n"
+"\n"
+"   :arg loop: The loop used for tangent calculation.\n"
+"   :type loop: :class:`BMLoop`\n"
+"   :return: a normalized vector.\n"
+"   :rtype: :class:`mathutils.Vector`\n"
+);
+static PyObject *bpy_bmedge_calc_tangent(BPy_BMEdge *self, PyObject *args)
+{
+	BPy_BMLoop *py_loop;
+	BPY_BM_CHECK_OBJ(self);
+
+	if (!PyArg_ParseTuple(args, "O!:BMEdge.calc_face_tangent",
+	                      &BPy_BMLoop_Type, &py_loop))
+	{
+		return NULL;
+	}
+	else {
+		float vec[3];
+		BPY_BM_CHECK_OBJ(py_loop);
+		/* no need to check if they are from the same mesh or even connected */
+		BM_edge_face_tangent(self->e, py_loop->l, vec);
+		return Vector_CreatePyObject(vec, 3, Py_NEW, NULL);
+	}
+}
+
 
 PyDoc_STRVAR(bpy_bmedge_other_vert_doc,
 ".. method:: other_vert(vert)\n"
@@ -2078,8 +2108,9 @@ static struct PyMethodDef bpy_bmedge_methods[] = {
 
     {"other_vert", (PyCFunction)bpy_bmedge_other_vert, METH_O, bpy_bmedge_other_vert_doc},
 
-    {"calc_length",     (PyCFunction)bpy_bmedge_calc_length,     METH_NOARGS, bpy_bmedge_calc_length_doc},
-    {"calc_face_angle", (PyCFunction)bpy_bmedge_calc_face_angle, METH_NOARGS, bpy_bmedge_calc_face_angle_doc},
+    {"calc_length",     (PyCFunction)bpy_bmedge_calc_length,     METH_NOARGS,  bpy_bmedge_calc_length_doc},
+    {"calc_face_angle", (PyCFunction)bpy_bmedge_calc_face_angle, METH_NOARGS,  bpy_bmedge_calc_face_angle_doc},
+    {"calc_tangent",    (PyCFunction)bpy_bmedge_calc_tangent,    METH_VARARGS, bpy_bmedge_calc_tangent_doc},
 
     {"normal_update",  (PyCFunction)bpy_bmedge_normal_update,  METH_NOARGS,  bpy_bmedge_normal_update_doc},