io_scene_fbx/export_fbx_bin.py

@@ -48,7 +48,7 @@ from .fbx_utils import (
     PerfMon,
     units_blender_to_fbx_factor, units_convertor, units_convertor_iter,
     matrix4_to_array, similar_values, shape_difference_exclude_similar, astype_view_signedness, fast_first_axis_unique,
-    fast_first_axis_flat,
+    fast_first_axis_flat, fast_mesh_shape_key_co_foreach_get,
     # Attribute helpers.
     MESH_ATTRIBUTE_CORNER_EDGE, MESH_ATTRIBUTE_SHARP_EDGE, MESH_ATTRIBUTE_EDGE_VERTS, MESH_ATTRIBUTE_CORNER_VERT,
     MESH_ATTRIBUTE_SHARP_FACE, MESH_ATTRIBUTE_POSITION, MESH_ATTRIBUTE_MATERIAL_INDEX,
@@ -2753,7 +2753,7 @@ def fbx_data_from_scene(scene, depsgraph, settings):
                 _cos = MESH_ATTRIBUTE_POSITION.to_ndarray(me.attributes)
             else:
                 _cos = np.empty(len(me.vertices) * 3, dtype=co_bl_dtype)
-                shape_key.data.foreach_get("co", _cos)
+                fast_mesh_shape_key_co_foreach_get(shape_key, _cos)
             return vcos_transformed(_cos, geom_mat_co, co_fbx_dtype)
 
         for shape in me.shape_keys.key_blocks[1:]:

io_scene_fbx/fbx_utils.py

@@ -10,6 +10,7 @@ from collections import namedtuple
 from collections.abc import Iterable
 from itertools import zip_longest, chain
 from dataclasses import dataclass, field
+from types import SimpleNamespace
 from typing import Callable
 import numpy as np
 
@@ -659,6 +660,142 @@ def expand_shape_key_range(shape_key, value_to_fit):
         return True
 
 
+def _shape_key_co_memory_as_ndarray(shape_key, do_check=True):
+    """
+    ShapeKey.data elements have a dynamic typing based on the Object the shape keys are attached to, which makes them
+    slower to access with foreach_get. For 'MESH' type Objects, the elements are always ShapeKeyPoint type and their
+    data is stored contiguously, meaning an array can be constructed from the pointer to the first ShapeKeyPoint
+    element.
+
+    Creating an array from a pointer is inherently unsafe, so this function does a number of checks to make it safer.
+    """
+    if do_check and not _fast_mesh_shape_key_co_check():
+        return None
+    shape_data = shape_key.data
+    num_co = len(shape_data)
+
+    if num_co < 2:
+        # At least 2 elements are required to check memory size.
+        return None
+
+    co_dtype = np.dtype(np.single)
+
+    start_address = shape_data[0].as_pointer()
+    last_element_start_address = shape_data[-1].as_pointer()
+
+    memory_length_minus_one_item = last_element_start_address - start_address
+
+    expected_element_size = co_dtype.itemsize * 3
+    expected_memory_length = (num_co - 1) * expected_element_size
+
+    if memory_length_minus_one_item == expected_memory_length:
+        # Use NumPy's array interface protocol to construct an array from the pointer.
+        array_interface_holder = SimpleNamespace(
+            __array_interface__=dict(
+                shape=(num_co * 3,),
+                typestr=co_dtype.str,
+                data=(start_address, False),  # False for writable
+                version=3,
+            )
+        )
+        return np.asarray(array_interface_holder)
+    else:
+        return None
+
+
+# Initially set to None
+_USE_FAST_SHAPE_KEY_CO_FOREACH_GETSET = None
+
+
+def _fast_mesh_shape_key_co_check():
+    global _USE_FAST_SHAPE_KEY_CO_FOREACH_GETSET
+    if _USE_FAST_SHAPE_KEY_CO_FOREACH_GETSET is not None:
+        # The check has already been run and the result has been stored in _USE_FAST_SHAPE_KEY_CO_FOREACH_GETSET.
+        return _USE_FAST_SHAPE_KEY_CO_FOREACH_GETSET
+
+    # Check that accessing a shape key's data through its pointer works, by creating a temporary mesh and adding a shape
+    # key to it.
+    tmp_mesh = None
+    tmp_object = None
+    try:
+        tmp_mesh = bpy.data.meshes.new("")
+        num_co = 100
+        tmp_mesh.vertices.add(num_co)
+        # An Object is needed to add/remove shape keys from a Mesh.
+        tmp_object = bpy.data.objects.new("", tmp_mesh)
+        shape_key = tmp_object.shape_key_add(name="")
+        shape_data = shape_key.data
+
+        if shape_key.bl_rna.properties["data"].fixed_type == shape_data[0].bl_rna:
+            # The shape key "data" collection is no longer dynamically typed and foreach_get/set should be fast enough.
+            _USE_FAST_SHAPE_KEY_CO_FOREACH_GETSET = False
+            return False
+
+        co_dtype = np.dtype(np.single)
+
+        # Fill the shape key with some data.
+        shape_data.foreach_set("co", np.arange(3 * num_co, dtype=co_dtype))
+
+        # The check is this function, so explicitly don't do the check.
+        co_memory_as_array = _shape_key_co_memory_as_ndarray(shape_key, do_check=False)
+        if co_memory_as_array is not None:
+            # Immediately make a copy in the unlikely case the `foreach_get` call afterward can cause the memory to be
+            # reallocated.
+            co_array_from_memory = co_memory_as_array.copy()
+            del co_memory_as_array
+            # Check that the array created from the pointer has the exact same contents
+            # as using foreach_get.
+            co_array_from_foreach_get = np.empty(num_co * 3, dtype=co_dtype)
+            shape_data.foreach_get("co", co_array_from_foreach_get)
+            if np.array_equal(co_array_from_foreach_get, co_array_from_memory, equal_nan=True):
+                _USE_FAST_SHAPE_KEY_CO_FOREACH_GETSET = True
+                return True
+
+        # Something didn't work.
+        _USE_FAST_SHAPE_KEY_CO_FOREACH_GETSET = False
+        return False
+    finally:
+        # Clean up temporary objects.
+        if tmp_object is not None:
+            tmp_object.shape_key_clear()
+            bpy.data.objects.remove(tmp_object)
+        if tmp_mesh is not None:
+            bpy.data.meshes.remove(tmp_mesh)
+
+
+def fast_mesh_shape_key_co_foreach_get(shape_key, seq):
+    """
+    Replacement for ShapeKey.data.foreach_get that accesses the shape key data's memory directly if possible.
+    """
+    co_memory_as_array = _shape_key_co_memory_as_ndarray(shape_key)
+    if co_memory_as_array is not None:
+        seq[:] = co_memory_as_array
+    else:
+        shape_key.data.foreach_get("co", seq)
+
+
+def fast_mesh_shape_key_dvcos_foreach_set(new_shape_key, dvcos, indices, mesh_positions_fallback_vector_view):
+    """
+    Apply sparse FBX shape key vectors to a newly created shape key.
+
+    The newly created shape key must have been created with `from_mix=False`, so that its coordinates match the mesh
+    positions.
+    """
+    co_memory_as_array = _shape_key_co_memory_as_ndarray(new_shape_key)
+    if co_memory_as_array is not None:
+        co_memory_as_array_vector_view = co_memory_as_array.view()
+        co_memory_as_array_vector_view.shape = (-1, 3)
+        co_memory_as_array_vector_view[indices] += dvcos
+        # Memory has been set directly, so call .update().
+        new_shape_key.data.update()
+    else:
+        # As a fallback, copy the mesh positions, apply the sparse vectors to that copy and then set all the shape key
+        # coordinates to the modified copy of the mesh positions.
+        shape_cos = mesh_positions_fallback_vector_view.copy()
+        shape_cos[indices] += dvcos
+        new_shape_key.data.foreach_set("co", shape_cos.ravel())
+
+
 # ##### Attribute utils. #####
 AttributeDataTypeInfo = namedtuple("AttributeDataTypeInfo", ["dtype", "foreach_attribute", "item_size"])
 _attribute_data_type_info_lookup = {

io_scene_fbx/import_fbx.py

@@ -51,6 +51,7 @@ from .fbx_utils import (
     FBX_KTIME_V7,
     FBX_KTIME_V8,
     FBX_TIMECODE_DEFINITION_TO_KTIME_PER_SECOND,
+    fast_mesh_shape_key_dvcos_foreach_set,
 )
 
 LINEAR_INTERPOLATION_VALUE = bpy.types.Keyframe.bl_rna.properties['interpolation'].enum_items['LINEAR'].value
@@ -2000,9 +2001,7 @@ def blen_read_shapes(fbx_tmpl, fbx_data, objects, me, scene):
 
         # Only need to set the shape key co if there are any non-zero dvcos.
         if dvcos.any():
-            shape_cos = me_vcos_vector_view.copy()
-            shape_cos[indices] += dvcos
-            kb.data.foreach_set("co", shape_cos.ravel())
+            fast_mesh_shape_key_dvcos_foreach_set(kb, dvcos, indices, me_vcos_vector_view)
 
         shape_key_values_in_range &= expand_shape_key_range(kb, weight)