bmesh py api: change .from_mesh() / .to_mesh() to be class methods of BMesh rather than functions in the module.

added example script which converts a mesh to a bmesh, edits and converts back again.

release/scripts/templates/bmesh_simple.py

@@ -0,0 +1,21 @@
+# This example assumes we have a mesh object selected
+
+import bpy
+import bmesh
+
+# Get the active mesh
+me = bpy.context.object.data
+
+
+# Get a BMesh representation
+bm = bmesh.new()   # create an empty BMesh
+bm.from_mesh(me)   # fill it in from a Mesh
+
+
+# Modify the BMesh, can do anything here...
+for v in bm.verts:
+    v.co.x += 1.0
+
+
+# Finish up, write the bmesh back to the mesh
+bm.to_mesh(me)

source/blender/python/bmesh/bmesh_py_api.c

@@ -40,17 +40,14 @@
 #include "BLI_utildefines.h"
 
 #include "BKE_tessmesh.h"
-#include "BKE_depsgraph.h"
 
 #include "DNA_mesh_types.h"
-#include "DNA_object_types.h"
 
 #include "../generic/py_capi_utils.h"
 
 #include "bmesh_py_api.h" /* own include */
 
 
-
 PyDoc_STRVAR(bpy_bm_new_doc,
 ".. method:: new()\n"
 "\n"
@@ -70,88 +67,40 @@ static PyObject *bpy_bm_new(PyObject *UNUSED(self))
 	return (PyObject *)py_bmesh;
 }
 
-PyDoc_STRVAR(bpy_bm_from_mesh_doc,
-".. method:: from_mesh(mesh)\n"
+PyDoc_STRVAR(bpy_bm_from_edit_mesh_doc,
+".. method:: from_edit_mesh(mesh)\n"
 "\n"
 "   Return a BMesh from this mesh, currently the mesh must already be in editmode.\n"
 "\n"
 "   :return: the BMesh assosiated with this mesh.\n"
 "   :rtype: :class:`bmesh.types.BMesh`\n"
 );
-
-static PyObject *bpy_bm_from_mesh(PyObject *UNUSED(self), PyObject *value)
+static PyObject *bpy_bm_from_edit_mesh(PyObject *UNUSED(self), PyObject *value)
 {
 	BPy_BMesh *py_bmesh;
 	BMesh *bm;
 	Mesh *me = PyC_RNA_AsPointer(value, "Mesh");
-	int py_owns;
 
 	if (me == NULL) {
 		return NULL;
 	}
 
-	/* temp! */
-	if (!me->edit_btmesh) {
-		bm = BM_mesh_create(NULL, &bm_mesh_allocsize_default);
-		BM_mesh_to_bmesh(bm, me, 0, 0); /* BMESH_TODO add args */
-		py_owns = TRUE;
-	}
-	else {
-		bm = me->edit_btmesh->bm;
-		py_owns = FALSE;
+	if (me->edit_btmesh == NULL) {
+		PyErr_SetString(PyExc_ValueError,
+		                "The mesh must be in editmode");
+		return NULL;
 	}
 
+	bm = me->edit_btmesh->bm;
+
 	py_bmesh = (BPy_BMesh *)BPy_BMesh_CreatePyObject(bm);
-	py_bmesh->py_owns = py_owns;
+	py_bmesh->py_owns = FALSE;
 	return (PyObject *)py_bmesh;
 }
 
-PyDoc_STRVAR(bpy_bm_to_mesh_doc,
-".. method:: to_mesh(mesh, bmesh)\n"
-"\n"
-"   Return a BMesh from this mesh, currently the mesh must already be in editmode.\n"
-"\n"
-"   :return: the BMesh assosiated with this mesh.\n"
-"   :rtype: :class:`bmesh.types.BMesh`\n"
-);
-
-static PyObject *bpy_bm_to_mesh(PyObject *UNUSED(self), PyObject *args)
-{
-	PyObject  *py_mesh;
-	BPy_BMesh *py_bmesh;
-	Mesh  *me;
-	BMesh *bm;
-
-	if (!PyArg_ParseTuple(args, "OO!:to_mesh", &py_mesh, &BPy_BMesh_Type, &py_bmesh) ||
-	    !(me = PyC_RNA_AsPointer(py_mesh, "Mesh")))
-	{
-		return NULL;
-	}
-
-	BPY_BM_CHECK_OBJ(py_bmesh);
-
-	if (me->edit_btmesh) {
-		PyErr_Format(PyExc_ValueError,
-		             "to_mesh(): Mesh '%s' is in editmode", me->id.name + 2);
-		return NULL;
-	}
-
-	bm = py_bmesh->bm;
-
-	BM_mesh_from_bmesh(bm, me, FALSE);
-
-	/* we could have the user do this but if they forget blender can easy crash
-	 * since the references arrays for the objects derived meshes are now invalid */
-	DAG_id_tag_update(&me->id, OB_RECALC_DATA);
-
-	Py_RETURN_NONE;
-}
-
 static struct PyMethodDef BPy_BM_methods[] = {
-    /* THESE NAMES MAY CHANGE! */
     {"new",            (PyCFunction)bpy_bm_new,            METH_NOARGS,  bpy_bm_new_doc},
-    {"from_mesh", (PyCFunction)bpy_bm_from_mesh, METH_O,       bpy_bm_from_mesh_doc},
-    {"to_mesh",   (PyCFunction)bpy_bm_to_mesh,   METH_VARARGS, bpy_bm_to_mesh_doc},
+    {"from_edit_mesh", (PyCFunction)bpy_bm_from_edit_mesh, METH_O,       bpy_bm_from_edit_mesh_doc},
     {NULL, NULL, 0, NULL}
 };
 
@@ -163,6 +112,12 @@ PyDoc_STRVAR(BPy_BM_doc,
 "\n"
 "* :mod:`bmesh.utils`\n"
 "* :mod:`bmesh.types`\n"
+"\n"
+"\n"
+"Example Script\n"
+"--------------\n"
+"\n"
+".. literalinclude:: ../../../release/scripts/templates/bmesh_simple.py\n"
 );
 static struct PyModuleDef BPy_BM_module_def = {
 	PyModuleDef_HEAD_INIT,
@@ -185,7 +140,6 @@ PyObject *BPyInit_bmesh(void)
 	BPy_BM_init_types();
 	BPy_BM_init_select_types();
 
-
 	mod = PyModule_Create(&BPy_BM_module_def);
 
 	/* bmesh.types */

source/blender/python/bmesh/bmesh_py_types.c

@@ -31,6 +31,10 @@
 
 #include "BLI_math.h"
 
+#include "DNA_mesh_types.h"
+#include "DNA_object_types.h"
+
+#include "BKE_depsgraph.h"
 #include "BKE_customdata.h"
 
 #include "bmesh.h"
@@ -586,6 +590,82 @@ static PyGetSetDef bpy_bmloop_getseters[] = {
 /* Mesh
  * ---- */
 
+PyDoc_STRVAR(bpy_bmesh_to_mesh_doc,
+".. method:: to_mesh(mesh)\n"
+"\n"
+"   Writes this BMesh data into an existing Mesh datablock.\n"
+"\n"
+"   :arg mesh: The mesh data to write into.\n"
+"   :type mesh: :class:`Mesh`\n"
+);
+static PyObject *bpy_bmesh_to_mesh(BPy_BMesh *self, PyObject *args)
+{
+	PyObject  *py_mesh;
+	Mesh  *me;
+	BMesh *bm;
+
+	BPY_BM_CHECK_OBJ(self);
+
+	if (!PyArg_ParseTuple(args, "O:to_mesh", &py_mesh) ||
+	    !(me = PyC_RNA_AsPointer(py_mesh, "Mesh")))
+	{
+		return NULL;
+	}
+
+	/* we could allow this but its almost certainly _not_ what script authors want */
+	if (me->edit_btmesh) {
+		PyErr_Format(PyExc_ValueError,
+		             "to_mesh(): Mesh '%s' is in editmode", me->id.name + 2);
+		return NULL;
+	}
+
+	bm = self->bm;
+
+	BM_mesh_from_bmesh(bm, me, FALSE);
+
+	/* we could have the user do this but if they forget blender can easy crash
+	 * since the references arrays for the objects derived meshes are now invalid */
+	DAG_id_tag_update(&me->id, OB_RECALC_DATA);
+
+	Py_RETURN_NONE;
+}
+
+PyDoc_STRVAR(bpy_bmesh_from_mesh_doc,
+".. method:: from_mesh(mesh, use_shape_key=False, shape_key_index=0)\n"
+"\n"
+"   Initialize this bmesh from existing mesh datablock.\n"
+"\n"
+"   :arg mesh: The mesh data to load.\n"
+"   :type mesh: :class:`Mesh`\n"
+"   :arg use_shape_key: Use the locations from a shape key.\n"
+"   :type use_shape_key: boolean\n"
+"   :arg shape_key_index: The shape key index to use.\n"
+"   :type shape_key_index: int\n"
+);
+static PyObject *bpy_bmesh_from_mesh(BPy_BMesh *self, PyObject *args, PyObject *kw)
+{
+	static const char *kwlist[] = {"mesh", "use_shape_key", "shape_key_index", NULL};
+	BMesh *bm;
+	PyObject *py_mesh;
+	Mesh *me;
+	int use_shape_key = FALSE;
+	int shape_key_index = 0;
+
+	if (!PyArg_ParseTupleAndKeywords(args, kw, "O|ii:to_mesh", (char **)kwlist,
+	                                 &py_mesh, &use_shape_key, &shape_key_index) ||
+	    !(me = PyC_RNA_AsPointer(py_mesh, "Mesh")))
+	{
+		return NULL;
+	}
+
+	bm = self->bm;
+
+	BM_mesh_to_bmesh(bm, me, use_shape_key, shape_key_index + 1);
+
+	Py_RETURN_NONE;
+}
+
+
 PyDoc_STRVAR(bpy_bmesh_select_flush_mode_doc,
 ".. method:: select_flush_mode()\n"
 "\n"
@@ -1716,6 +1796,9 @@ static PyObject *bpy_bmelemseq_index_update(BPy_BMElemSeq *self)
 
 
 static struct PyMethodDef bpy_bmesh_methods[] = {
+    {"from_mesh", (PyCFunction)bpy_bmesh_from_mesh, METH_VARARGS | METH_KEYWORDS, bpy_bmesh_from_mesh_doc},
+    {"to_mesh",   (PyCFunction)bpy_bmesh_to_mesh,   METH_VARARGS,                 bpy_bmesh_to_mesh_doc},
+
     {"select_flush_mode", (PyCFunction)bpy_bmesh_select_flush_mode, METH_NOARGS, bpy_bmesh_select_flush_mode_doc},
     {"select_flush", (PyCFunction)bpy_bmesh_select_flush, METH_O, bpy_bmesh_select_flush_doc},
     {"normal_update", (PyCFunction)bpy_bmesh_normal_update, METH_VARARGS, bpy_bmesh_normal_update_doc},

source/blender/python/bmesh/bmesh_py_types.h

@@ -62,7 +62,7 @@ typedef struct BPy_BMElem {
 typedef struct BPy_BMesh {
 	PyObject_VAR_HEAD
 	struct BMesh *bm; /* keep first */
-	char py_owns;
+	char py_owns; /* when set, free along with the PyObject */
 } BPy_BMesh;
 
 /* element types */