bmesh py api:

added access to deform weights, access to weights acts like a python dict so you can do...

  print(group in dvert)
  dvert[group] = 0.5
  print(dvert[group])
  del dvert[group]
  print(dvert.items())

doc/python_api/rst/include__bmesh.rst

@@ -104,6 +104,25 @@ Here are some examples ...
         print("Vert Shape: %f, %f, %f" % (shape.x, shape.y, shape.z))
 
 
+.. code-block:: python
+
+   # in this example the active vertex group index is used,
+   # this is stored in the object, not the BMesh
+   group_index = obj.vertex_groups.active_index
+
+   # only ever one deform weight layer
+   dvert_lay = bm.verts.layers.deform.active
+
+   for vert in bm.verts:
+       dvert = vert[dvert_lay]
+		
+       if group_index in dvert:
+           print("Weight %f" % dvert[group_index])
+       else:
+           print("Setting Weight")
+           dvert[group_index] = 0.5
+
+
 Keeping a Correct State
 -----------------------
 

doc/python_api/sphinx_doc_gen.py

@@ -342,7 +342,8 @@ MODULE_GROUPING = {
                     "BMLayerCollection",
                     "BMLayerItem",
                     ("Custom-Data Layer Types", '-'),
-                    "BMLoopUV"
+                    "BMLoopUV",
+                    "BMDeformVert"
                     )
     }
 

source/blender/python/bmesh/bmesh_py_types.c

@@ -2836,6 +2836,7 @@ PyObject *BPyInit_bmesh_types(void)
 	mod_type_add(submodule, BPy_BMLayerItem_Type);
 	/* bmesh_py_types_meshdata.c */
 	mod_type_add(submodule, BPy_BMLoopUV_Type);
+	mod_type_add(submodule, BPy_BMDeformVert_Type);
 
 #undef mod_type_add
 

source/blender/python/bmesh/bmesh_py_types_customdata.c

@@ -361,10 +361,10 @@ static PyObject *bpy_bmlayercollection_get(BPy_BMLayerCollection *self, PyObject
 }
 
 static struct PyMethodDef bpy_bmelemseq_methods[] = {
-    {"keys",     (PyCFunction)bpy_bmlayercollection_keys,     METH_NOARGS,  bpy_bmlayercollection_keys_doc},
+    {"keys",    (PyCFunction)bpy_bmlayercollection_keys,     METH_NOARGS,  bpy_bmlayercollection_keys_doc},
-    {"values",   (PyCFunction)bpy_bmlayercollection_values,   METH_NOARGS,  bpy_bmlayercollection_values_doc},
+    {"values",  (PyCFunction)bpy_bmlayercollection_values,   METH_NOARGS,  bpy_bmlayercollection_values_doc},
-    {"items",    (PyCFunction)bpy_bmlayercollection_items,    METH_NOARGS,  bpy_bmlayercollection_items_doc},
+    {"items",   (PyCFunction)bpy_bmlayercollection_items,    METH_NOARGS,  bpy_bmlayercollection_items_doc},
-    {"get",      (PyCFunction)bpy_bmlayercollection_get,      METH_VARARGS, bpy_bmlayercollection_get_doc},
+    {"get",     (PyCFunction)bpy_bmlayercollection_get,      METH_VARARGS, bpy_bmlayercollection_get_doc},
 
     /* for later! */
 #if 0
@@ -774,8 +774,7 @@ PyObject *BPy_BMLayerItem_GetItem(BPy_BMElem *py_ele, BPy_BMLayerItem *py_layer)
 	switch (py_layer->type) {
 		case CD_MDEFORMVERT:
 		{
-			ret = Py_NotImplemented; /* TODO */
+			ret = BPy_BMDeformVert_CreatePyObject(value);
-			Py_INCREF(ret);
 			break;
 		}
 		case CD_PROP_FLT:
@@ -848,8 +847,7 @@ int BPy_BMLayerItem_SetItem(BPy_BMElem *py_ele, BPy_BMLayerItem *py_layer, PyObj
 	switch (py_layer->type) {
 		case CD_MDEFORMVERT:
 		{
-			PyErr_SetString(PyExc_AttributeError, "readonly"); /* could make this writeable later */
+			ret = BPy_BMDeformVert_AssignPyObject(value, py_value);
-			ret = -1;
 			break;
 		}
 		case CD_PROP_FLT:

source/blender/python/bmesh/bmesh_py_types_meshdata.c

@@ -39,6 +39,10 @@
 #include "BLI_utildefines.h"
 #include "BLI_math_vector.h"
 
+#include "BKE_deform.h"
+
+#include "bmesh_py_types_meshdata.h"
+
 /* Mesh Loop UV
  * ************ */
 
@@ -138,7 +142,7 @@ int BPy_BMLoopUV_AssignPyObject(struct MLoopUV *mloopuv, PyObject *value)
 		return -1;
 	}
 	else {
-		*((MLoopUV *)mloopuv) = *((MLoopUV *)((BPy_BMLoopUV *)value)->data);
+		*((MLoopUV *)mloopuv) = *(((BPy_BMLoopUV *)value)->data);
 		return 0;
 	}
 }
@@ -252,9 +256,333 @@ PyObject *BPy_BMLoopColor_CreatePyObject(struct MLoopCol *data)
 /* --- End Mesh Loop Color --- */
 
 
+/* Mesh Deform Vert
+ * **************** */
+
+/**
+ * This is python type wraps a deform vert as a python dictionary,
+ * hiding the #MDeformWeight on access, since the mapping is very close, eg:
+ *
+ * C:
+ *     weight = defvert_find_weight(dv, group_nr);
+ *     defvert_remove_group(dv, dw)
+ *
+ * Py:
+ *     weight = dv[group_nr]
+ *     del dv[group_nr]
+ *
+ * \note: there is nothing BMesh spesific here,
+ * its only that BMesh is the only part of blender that uses a hand written api like this.
+ * This type could eventually be used to access lattice weights.
+ *
+ * \note: Many of blender-api's dict-like-wrappers act like ordered dicts,
+ * This is intentional _not_ ordered, the weights can be in any order and it wont matter,
+ * the order should not be used in the api in any meaningful way (as with a python dict)
+ * only expose as mapping, not a sequence.
+ */
+
+#define BPy_BMDeformVert_Check(v)  (Py_TYPE(v) == &BPy_BMDeformVert_Type)
+
+typedef struct BPy_BMDeformVert {
+	PyObject_VAR_HEAD
+	MDeformVert *data;
+} BPy_BMDeformVert;
+
+
+/* Mapping Protocols
+ * ================= */
+
+static int bpy_bmdeformvert_len(BPy_BMDeformVert *self)
+{
+	return self->data->totweight;
+}
+
+static PyObject *bpy_bmdeformvert_subscript(BPy_BMDeformVert *self, PyObject *key)
+{
+	if (PyIndex_Check(key)) {
+		int i;
+		i = PyNumber_AsSsize_t(key, PyExc_IndexError);
+		if (i == -1 && PyErr_Occurred()) {
+			return NULL;
+		}
+		else {
+			MDeformWeight *dw = defvert_find_index(self->data, i);
+
+			if (dw == NULL) {
+				PyErr_SetString(PyExc_KeyError, "BMDeformVert[key] = x: "
+				                "key not found");
+				return NULL;
+			}
+			else {
+				return PyFloat_FromDouble(dw->weight);
+			}
+		}
+	}
+	else {
+		PyErr_Format(PyExc_TypeError,
+		             "BMDeformVert keys must be integers, not %.200s",
+		             Py_TYPE(key)->tp_name);
+		return NULL;
+	}
+}
+
+static int bpy_bmdeformvert_ass_subscript(BPy_BMDeformVert *self, PyObject *key, PyObject *value)
+{
+	if (PyIndex_Check(key)) {
+		int i;
+
+		i = PyNumber_AsSsize_t(key, PyExc_IndexError);
+		if (i == -1 && PyErr_Occurred()) {
+			return -1;
+		}
+
+		if (value) {
+			/* dvert[group_index] = 0.5 */
+			if (i < 0) {
+				PyErr_SetString(PyExc_KeyError, "BMDeformVert[key] = x: "
+								"weight keys can't be negative");
+				return -1;
+			}
+			else {
+				MDeformWeight *dw = defvert_verify_index(self->data, i);
+				const float f = PyFloat_AsDouble(value);
+				if (f == -1 && PyErr_Occurred()) { // parsed key not a number
+					PyErr_SetString(PyExc_TypeError,
+									"BMDeformVert[key] = x: "
+									"argument not a number");
+					return -1;
+				}
+
+				dw->weight = CLAMPIS(f, 0.0f, 1.0f);
+			}
+		}
+		else {
+			/* del dvert[group_index] */
+			MDeformWeight *dw = defvert_find_index(self->data, i);
+
+			if (dw == NULL) {
+				PyErr_SetString(PyExc_KeyError, "del BMDeformVert[key]: "
+				                "key not found");
+			}
+			defvert_remove_group(self->data, dw);
+		}
+
+		return 0;
+
+	}
+	else {
+		PyErr_Format(PyExc_TypeError,
+		             "BMDeformVert keys must be integers, not %.200s",
+		             Py_TYPE(key)->tp_name);
+		return -1;
+	}
+}
+
+static int bpy_bmdeformvert_contains(BPy_BMDeformVert *self, PyObject *value)
+{
+	const int key = PyLong_AsSsize_t(value);
+
+	if (key == -1 && PyErr_Occurred()) {
+		PyErr_SetString(PyExc_TypeError,
+		                "BMDeformVert.__contains__: expected an int");
+		return -1;
+	}
+
+	return (defvert_find_index(self->data, key) != NULL) ? 1 : 0;
+}
+
+/* only defined for __contains__ */
+static PySequenceMethods bpy_bmdeformvert_as_sequence = {
+    (lenfunc)bpy_bmdeformvert_len,               /* sq_length */
+    NULL,                                        /* sq_concat */
+    NULL,                                        /* sq_repeat */
+
+    /* note: if this is set PySequence_Check() returns True,
+     * but in this case we dont want to be treated as a seq */
+    NULL,                                        /* sq_item */
+
+    NULL,                                        /* sq_slice */
+    NULL,                                        /* sq_ass_item */
+    NULL,                                        /* *was* sq_ass_slice */
+    (objobjproc)bpy_bmdeformvert_contains,  /* sq_contains */
+    (binaryfunc) NULL,                           /* sq_inplace_concat */
+    (ssizeargfunc) NULL,                         /* sq_inplace_repeat */
+};
+
+static PyMappingMethods bpy_bmdeformvert_as_mapping = {
+	(lenfunc)bpy_bmdeformvert_len,
+	(binaryfunc)bpy_bmdeformvert_subscript,
+	(objobjargproc)bpy_bmdeformvert_ass_subscript
+};
+
+/* Methods
+ * ======= */
+
+PyDoc_STRVAR(bpy_bmdeformvert_keys_doc,
+".. method:: keys()\n"
+"\n"
+"   Return the group indices used by this vertex\n"
+"   (matching pythons dict.keys() functionality).\n"
+"\n"
+"   :return: the deform group this vertex uses\n"
+"   :rtype: list of ints\n"
+);
+static PyObject *bpy_bmdeformvert_keys(BPy_BMDeformVert *self)
+{
+	PyObject *ret;
+	int i;
+	MDeformWeight *dw = self->data->dw;
+
+	ret = PyList_New(self->data->totweight);
+	for (i = 0; i < self->data->totweight; i++, dw++) {
+		PyList_SET_ITEM(ret, i, PyLong_FromSsize_t(dw->def_nr));
+	}
+
+	return ret;
+}
+
+PyDoc_STRVAR(bpy_bmdeformvert_values_doc,
+".. method:: items()\n"
+"\n"
+"   Return (group, weight) pairs for this vertex\n"
+"   (matching pythons dict.items() functionality).\n"
+"\n"
+"   :return: (key, value) pairs for each deform weight of this vertex.\n"
+"   :rtype: list of tuples\n"
+);
+static PyObject *bpy_bmdeformvert_values(BPy_BMDeformVert *self)
+{
+	PyObject *ret;
+	int i;
+	MDeformWeight *dw = self->data->dw;
+
+	ret = PyList_New(self->data->totweight);
+	for (i = 0; i < self->data->totweight; i++, dw++) {
+		PyList_SET_ITEM(ret, i, PyFloat_FromDouble(dw->weight));
+	}
+
+	return ret;
+}
+
+PyDoc_STRVAR(bpy_bmdeformvert_items_doc,
+".. method:: values()\n"
+"\n"
+"   Return the weights of the deform vertex\n"
+"   (matching pythons dict.values() functionality).\n"
+"\n"
+"   :return: The weights that influence this vertex\n"
+"   :rtype: list of floats\n"
+);
+static PyObject *bpy_bmdeformvert_items(BPy_BMDeformVert *self)
+{
+	PyObject *ret;
+	PyObject *item;
+	int i;
+	MDeformWeight *dw = self->data->dw;
+
+	ret = PyList_New(self->data->totweight);
+	for (i = 0; i < self->data->totweight; i++, dw++) {
+		item = PyTuple_New(2);
+
+		PyTuple_SET_ITEM(item, 0, PyLong_FromSsize_t(dw->def_nr));
+		PyTuple_SET_ITEM(item, 1, PyFloat_FromDouble(dw->weight));
+
+		PyList_SET_ITEM(ret, i, item);
+	}
+
+	return ret;
+}
+
+PyDoc_STRVAR(bpy_bmdeformvert_get_doc,
+".. method:: get(key, default=None)\n"
+"\n"
+"   Returns the deform weight matching the key or default\n"
+"   when not found (matches pythons dictionary function of the same name).\n"
+"\n"
+"   :arg key: The key associated with deform weight.\n"
+"   :type key: int\n"
+"   :arg default: Optional argument for the value to return if\n"
+"      *key* is not found.\n"
+"   :type default: Undefined\n"
+);
+static PyObject *bpy_bmdeformvert_get(BPy_BMDeformVert *self, PyObject *args)
+{
+	int key;
+	PyObject *def = Py_None;
+
+	if (!PyArg_ParseTuple(args, "i|O:get", &key, &def)) {
+		return NULL;
+	}
+	else {
+		MDeformWeight *dw = defvert_find_index(self->data, key);
+
+		if (dw) {
+			return PyFloat_FromDouble(dw->weight);
+		}
+		else {
+			return Py_INCREF(def), def;
+		}
+	}
+}
+
+static struct PyMethodDef bpy_bmdeformvert_methods[] = {
+    {"keys",    (PyCFunction)bpy_bmdeformvert_keys,    METH_NOARGS,  bpy_bmdeformvert_keys_doc},
+    {"values",  (PyCFunction)bpy_bmdeformvert_values,  METH_NOARGS,  bpy_bmdeformvert_values_doc},
+    {"items",   (PyCFunction)bpy_bmdeformvert_items,   METH_NOARGS,  bpy_bmdeformvert_items_doc},
+    {"get",     (PyCFunction)bpy_bmdeformvert_get,     METH_VARARGS, bpy_bmdeformvert_get_doc},
+    /* BMESH_TODO */
+    {NULL, NULL, 0, NULL}
+};
+
+PyTypeObject BPy_BMDeformVert_Type = {{{0}}}; /* bm.loops.layers.uv.active */
+
+static void bm_init_types_bmdvert(void)
+{
+	BPy_BMDeformVert_Type.tp_basicsize = sizeof(BPy_BMDeformVert);
+
+	BPy_BMDeformVert_Type.tp_name = "BMDeformVert";
+
+	BPy_BMDeformVert_Type.tp_doc = NULL; // todo
+
+	BPy_BMDeformVert_Type.tp_as_sequence = &bpy_bmdeformvert_as_sequence;
+	BPy_BMDeformVert_Type.tp_as_mapping = &bpy_bmdeformvert_as_mapping;
+
+	BPy_BMDeformVert_Type.tp_methods = bpy_bmdeformvert_methods;
+
+	BPy_BMDeformVert_Type.tp_flags = Py_TPFLAGS_DEFAULT;
+
+	PyType_Ready(&BPy_BMDeformVert_Type);
+}
+
+int BPy_BMDeformVert_AssignPyObject(struct MDeformVert *dvert, PyObject *value)
+{
+	if (UNLIKELY(!BPy_BMDeformVert_Check(value))) {
+		PyErr_Format(PyExc_TypeError, "expected BMDeformVert, not a %.200s", Py_TYPE(value)->tp_name);
+		return -1;
+	}
+	else {
+		MDeformVert *dvert_src = ((BPy_BMDeformVert *)value)->data;
+		if (LIKELY(dvert != dvert_src)) {
+			defvert_copy(dvert, dvert_src);
+		}
+		return 0;
+	}
+}
+
+PyObject *BPy_BMDeformVert_CreatePyObject(struct MDeformVert *dvert)
+{
+	BPy_BMDeformVert *self = PyObject_New(BPy_BMDeformVert, &BPy_BMDeformVert_Type);
+	self->data = dvert;
+	return (PyObject *)self;
+}
+
+/* --- End Mesh Deform Vert --- */
+
+
 /* call to init all types */
 void BPy_BM_init_types_meshdata(void)
 {
 	bm_init_types_bmloopuv();
 	bm_init_types_bmloopcol();
+	bm_init_types_bmdvert();
 }

source/blender/python/bmesh/bmesh_py_types_meshdata.h

@@ -31,6 +31,7 @@
 #define __BMESH_PY_TYPES_MESHDATA_H__
 
 extern PyTypeObject BPy_BMLoopUV_Type;
+extern PyTypeObject BPy_BMDeformVert_Type;
 
 #define BPy_BMLoopUV_Check(v)  (Py_TYPE(v) == &BPy_BMLoopUV_Type)
 
@@ -40,12 +41,18 @@ typedef struct BPy_BMGenericMeshData {
 } BPy_BMGenericMeshData;
 
 struct MLoopUV;
+struct MLoopCol;
+struct MDeformVert;
 
 int       BPy_BMLoopUV_AssignPyObject(struct MLoopUV *data, PyObject *value);
 PyObject *BPy_BMLoopUV_CreatePyObject(struct MLoopUV *data);
 
-int       BPy_BMLoopColor_AssignPyObject(struct MLoopUV *data, PyObject *value);
+int       BPy_BMLoopColor_AssignPyObject(struct MLoopCol *data, PyObject *value);
-PyObject *BPy_BMLoopColor_CreatePyObject(struct MLoopUV *data);
+PyObject *BPy_BMLoopColor_CreatePyObject(struct MLoopCol *data);
+
+int       BPy_BMDeformVert_AssignPyObject(struct MDeformVert *dvert, PyObject *value);
+PyObject *BPy_BMDeformVert_CreatePyObject(struct MDeformVert *dvert);
+
 
 void BPy_BM_init_types_meshdata(void);
 

source/blender/python/mathutils/mathutils_Color.c

@@ -194,7 +194,7 @@ static PyObject *Color_item(ColorObject *self, int i)
 
 	if (i < 0 || i >= COLOR_SIZE) {
 		PyErr_SetString(PyExc_IndexError,
-		                "color[attribute]: "
+		                "color[item]: "
 		                "array index out of range");
 		return NULL;
 	}
@@ -213,7 +213,7 @@ static int Color_ass_item(ColorObject *self, int i, PyObject *value)
 
 	if (f == -1 && PyErr_Occurred()) { // parsed item not a number
 		PyErr_SetString(PyExc_TypeError,
-		                "color[attribute] = x: "
+		                "color[item] = x: "
 		                "argument not a number");
 		return -1;
 	}
@@ -221,7 +221,7 @@ static int Color_ass_item(ColorObject *self, int i, PyObject *value)
 	if (i < 0) i = COLOR_SIZE - i;
 
 	if (i < 0 || i >= COLOR_SIZE) {
-		PyErr_SetString(PyExc_IndexError, "color[attribute] = x: "
+		PyErr_SetString(PyExc_IndexError, "color[item] = x: "
 		                "array assignment index out of range");
 		return -1;
 	}