export_fbx_bin.py

# ##### BEGIN GPL LICENSE BLOCK #####
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
#  of the License, or (at your option) any later version.
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#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
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#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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# ##### END GPL LICENSE BLOCK #####

# <pep8 compliant>

# Script copyright (C) Campbell Barton, Bastien Montagne


import array
import datetime
import math
import os
import time

from itertools import zip_longest, chain

if "bpy" in locals():
    import importlib
    if "encode_bin" in locals():
        importlib.reload(encode_bin)
    if "data_types" in locals():
        importlib.reload(data_types)
    if "fbx_utils" in locals():
        importlib.reload(fbx_utils)

import bpy
import bpy_extras
from bpy_extras import node_shader_utils
from mathutils import Vector, Matrix

from . import encode_bin, data_types, fbx_utils
from .fbx_utils import (
    # Constants.
    FBX_VERSION, FBX_HEADER_VERSION, FBX_SCENEINFO_VERSION, FBX_TEMPLATES_VERSION,
    FBX_MODELS_VERSION,
    FBX_GEOMETRY_VERSION, FBX_GEOMETRY_NORMAL_VERSION, FBX_GEOMETRY_BINORMAL_VERSION, FBX_GEOMETRY_TANGENT_VERSION,
    FBX_GEOMETRY_SMOOTHING_VERSION, FBX_GEOMETRY_CREASE_VERSION, FBX_GEOMETRY_VCOLOR_VERSION, FBX_GEOMETRY_UV_VERSION,
    FBX_GEOMETRY_MATERIAL_VERSION, FBX_GEOMETRY_LAYER_VERSION,
    FBX_GEOMETRY_SHAPE_VERSION, FBX_DEFORMER_SHAPE_VERSION, FBX_DEFORMER_SHAPECHANNEL_VERSION,
    FBX_POSE_BIND_VERSION, FBX_DEFORMER_SKIN_VERSION, FBX_DEFORMER_CLUSTER_VERSION,
    FBX_MATERIAL_VERSION, FBX_TEXTURE_VERSION,
    FBX_ANIM_KEY_VERSION,
    FBX_ANIM_PROPSGROUP_NAME,
    FBX_KTIME,
    BLENDER_OTHER_OBJECT_TYPES, BLENDER_OBJECT_TYPES_MESHLIKE,
    FBX_LIGHT_TYPES, FBX_LIGHT_DECAY_TYPES,
    RIGHT_HAND_AXES, FBX_FRAMERATES,
    # Miscellaneous utils.
    PerfMon,
    units_blender_to_fbx_factor, units_convertor, units_convertor_iter,
    matrix4_to_array, similar_values, similar_values_iter,
    # Mesh transform helpers.
    vcos_transformed_gen, nors_transformed_gen,
    # UUID from key.
    get_fbx_uuid_from_key,
    # Key generators.
    get_blenderID_key, get_blenderID_name,
    get_blender_mesh_shape_key, get_blender_mesh_shape_channel_key,
    get_blender_empty_key, get_blender_bone_key,
    get_blender_bindpose_key, get_blender_armature_skin_key, get_blender_bone_cluster_key,
    get_blender_anim_id_base, get_blender_anim_stack_key, get_blender_anim_layer_key,
    get_blender_anim_curve_node_key, get_blender_anim_curve_key,
    get_blender_nodetexture_key,
    # FBX element data.
    elem_empty,
    elem_data_single_bool, elem_data_single_int16, elem_data_single_int32, elem_data_single_int64,
    elem_data_single_float32, elem_data_single_float64,
    elem_data_single_bytes, elem_data_single_string, elem_data_single_string_unicode,
    elem_data_single_bool_array, elem_data_single_int32_array, elem_data_single_int64_array,
    elem_data_single_float32_array, elem_data_single_float64_array, elem_data_vec_float64,
    # FBX element properties.
    elem_properties, elem_props_set, elem_props_compound,
    # FBX element properties handling templates.
    elem_props_template_init, elem_props_template_set, elem_props_template_finalize,
    # Templates.
    FBXTemplate, fbx_templates_generate,
    # Animation.
    AnimationCurveNodeWrapper,
    # Objects.
    ObjectWrapper, fbx_name_class,
    # Top level.
    FBXExportSettingsMedia, FBXExportSettings, FBXExportData,
)

# Units converters!
convert_sec_to_ktime = units_convertor("second", "ktime")
convert_sec_to_ktime_iter = units_convertor_iter("second", "ktime")

convert_mm_to_inch = units_convertor("millimeter", "inch")

convert_rad_to_deg = units_convertor("radian", "degree")
convert_rad_to_deg_iter = units_convertor_iter("radian", "degree")


# ##### Templates #####
# TODO: check all those "default" values, they should match Blender's default as much as possible, I guess?

def fbx_template_def_globalsettings(scene, settings, override_defaults=None, nbr_users=0):
    props = {}
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"GlobalSettings", b"", props, nbr_users, [False])


def fbx_template_def_model(scene, settings, override_defaults=None, nbr_users=0):
    gscale = settings.global_scale
    props = {
        # Name,                  Value, Type, Animatable
        b"QuaternionInterpolate": (0, "p_enum", False),  # 0 = no quat interpolation.
        b"RotationOffset": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"RotationPivot": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"ScalingOffset": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"ScalingPivot": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"TranslationActive": (False, "p_bool", False),
        b"TranslationMin": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"TranslationMax": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"TranslationMinX": (False, "p_bool", False),
        b"TranslationMinY": (False, "p_bool", False),
        b"TranslationMinZ": (False, "p_bool", False),
        b"TranslationMaxX": (False, "p_bool", False),
        b"TranslationMaxY": (False, "p_bool", False),
        b"TranslationMaxZ": (False, "p_bool", False),
        b"RotationOrder": (0, "p_enum", False),  # we always use 'XYZ' order.
        b"RotationSpaceForLimitOnly": (False, "p_bool", False),
        b"RotationStiffnessX": (0.0, "p_double", False),
        b"RotationStiffnessY": (0.0, "p_double", False),
        b"RotationStiffnessZ": (0.0, "p_double", False),
        b"AxisLen": (10.0, "p_double", False),
        b"PreRotation": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"PostRotation": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"RotationActive": (False, "p_bool", False),
        b"RotationMin": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"RotationMax": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"RotationMinX": (False, "p_bool", False),
        b"RotationMinY": (False, "p_bool", False),
        b"RotationMinZ": (False, "p_bool", False),
        b"RotationMaxX": (False, "p_bool", False),
        b"RotationMaxY": (False, "p_bool", False),
        b"RotationMaxZ": (False, "p_bool", False),
        b"InheritType": (0, "p_enum", False),  # RrSs
        b"ScalingActive": (False, "p_bool", False),
        b"ScalingMin": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"ScalingMax": ((1.0, 1.0, 1.0), "p_vector_3d", False),
        b"ScalingMinX": (False, "p_bool", False),
        b"ScalingMinY": (False, "p_bool", False),
        b"ScalingMinZ": (False, "p_bool", False),
        b"ScalingMaxX": (False, "p_bool", False),
        b"ScalingMaxY": (False, "p_bool", False),
        b"ScalingMaxZ": (False, "p_bool", False),
        b"GeometricTranslation": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"GeometricRotation": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"GeometricScaling": ((1.0, 1.0, 1.0), "p_vector_3d", False),
        b"MinDampRangeX": (0.0, "p_double", False),
        b"MinDampRangeY": (0.0, "p_double", False),
        b"MinDampRangeZ": (0.0, "p_double", False),
        b"MaxDampRangeX": (0.0, "p_double", False),
        b"MaxDampRangeY": (0.0, "p_double", False),
        b"MaxDampRangeZ": (0.0, "p_double", False),
        b"MinDampStrengthX": (0.0, "p_double", False),
        b"MinDampStrengthY": (0.0, "p_double", False),
        b"MinDampStrengthZ": (0.0, "p_double", False),
        b"MaxDampStrengthX": (0.0, "p_double", False),
        b"MaxDampStrengthY": (0.0, "p_double", False),
        b"MaxDampStrengthZ": (0.0, "p_double", False),
        b"PreferedAngleX": (0.0, "p_double", False),
        b"PreferedAngleY": (0.0, "p_double", False),
        b"PreferedAngleZ": (0.0, "p_double", False),
        b"LookAtProperty": (None, "p_object", False),
        b"UpVectorProperty": (None, "p_object", False),
        b"Show": (True, "p_bool", False),
        b"NegativePercentShapeSupport": (True, "p_bool", False),
        b"DefaultAttributeIndex": (-1, "p_integer", False),
        b"Freeze": (False, "p_bool", False),
        b"LODBox": (False, "p_bool", False),
        b"Lcl Translation": ((0.0, 0.0, 0.0), "p_lcl_translation", True),
        b"Lcl Rotation": ((0.0, 0.0, 0.0), "p_lcl_rotation", True),
        b"Lcl Scaling": ((1.0, 1.0, 1.0), "p_lcl_scaling", True),
        b"Visibility": (1.0, "p_visibility", True),
        b"Visibility Inheritance": (1, "p_visibility_inheritance", False),
    }
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"Model", b"FbxNode", props, nbr_users, [False])


def fbx_template_def_null(scene, settings, override_defaults=None, nbr_users=0):
    props = {
        b"Color": ((0.8, 0.8, 0.8), "p_color_rgb", False),
        b"Size": (100.0, "p_double", False),
        b"Look": (1, "p_enum", False),  # Cross (0 is None, i.e. invisible?).
    }
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"NodeAttribute", b"FbxNull", props, nbr_users, [False])


def fbx_template_def_light(scene, settings, override_defaults=None, nbr_users=0):
    gscale = settings.global_scale
    props = {
        b"LightType": (0, "p_enum", False),  # Point light.
        b"CastLight": (True, "p_bool", False),
        b"Color": ((1.0, 1.0, 1.0), "p_color", True),
        b"Intensity": (100.0, "p_number", True),  # Times 100 compared to Blender values...
        b"DecayType": (2, "p_enum", False),  # Quadratic.
        b"DecayStart": (30.0 * gscale, "p_double", False),
        b"CastShadows": (True, "p_bool", False),
        b"ShadowColor": ((0.0, 0.0, 0.0), "p_color", True),
        b"AreaLightShape": (0, "p_enum", False),  # Rectangle.
    }
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"NodeAttribute", b"FbxLight", props, nbr_users, [False])


def fbx_template_def_camera(scene, settings, override_defaults=None, nbr_users=0):
    r = scene.render
    props = {
        b"Color": ((0.8, 0.8, 0.8), "p_color_rgb", False),
        b"Position": ((0.0, 0.0, -50.0), "p_vector", True),
        b"UpVector": ((0.0, 1.0, 0.0), "p_vector", True),
        b"InterestPosition": ((0.0, 0.0, 0.0), "p_vector", True),
        b"Roll": (0.0, "p_roll", True),
        b"OpticalCenterX": (0.0, "p_opticalcenterx", True),
        b"OpticalCenterY": (0.0, "p_opticalcentery", True),
        b"BackgroundColor": ((0.63, 0.63, 0.63), "p_color", True),
        b"TurnTable": (0.0, "p_number", True),
        b"DisplayTurnTableIcon": (False, "p_bool", False),
        b"UseMotionBlur": (False, "p_bool", False),
        b"UseRealTimeMotionBlur": (True, "p_bool", False),
        b"Motion Blur Intensity": (1.0, "p_number", True),
        b"AspectRatioMode": (0, "p_enum", False),  # WindowSize.
        b"AspectWidth": (320.0, "p_double", False),
        b"AspectHeight": (200.0, "p_double", False),
        b"PixelAspectRatio": (1.0, "p_double", False),
        b"FilmOffsetX": (0.0, "p_number", True),
        b"FilmOffsetY": (0.0, "p_number", True),
        b"FilmWidth": (0.816, "p_double", False),
        b"FilmHeight": (0.612, "p_double", False),
        b"FilmAspectRatio": (1.3333333333333333, "p_double", False),
        b"FilmSqueezeRatio": (1.0, "p_double", False),
        b"FilmFormatIndex": (0, "p_enum", False),  # Assuming this is ApertureFormat, 0 = custom.
        b"PreScale": (1.0, "p_number", True),
        b"FilmTranslateX": (0.0, "p_number", True),
        b"FilmTranslateY": (0.0, "p_number", True),
        b"FilmRollPivotX": (0.0, "p_number", True),
        b"FilmRollPivotY": (0.0, "p_number", True),
        b"FilmRollValue": (0.0, "p_number", True),
        b"FilmRollOrder": (0, "p_enum", False),  # 0 = rotate first (default).
        b"ApertureMode": (2, "p_enum", False),  # 2 = Vertical.
        b"GateFit": (0, "p_enum", False),  # 0 = no resolution gate fit.
        b"FieldOfView": (25.114999771118164, "p_fov", True),
        b"FieldOfViewX": (40.0, "p_fov_x", True),
        b"FieldOfViewY": (40.0, "p_fov_y", True),
        b"FocalLength": (34.89327621672628, "p_number", True),
        b"CameraFormat": (0, "p_enum", False),  # Custom camera format.
        b"UseFrameColor": (False, "p_bool", False),
        b"FrameColor": ((0.3, 0.3, 0.3), "p_color_rgb", False),
        b"ShowName": (True, "p_bool", False),
        b"ShowInfoOnMoving": (True, "p_bool", False),
        b"ShowGrid": (True, "p_bool", False),
        b"ShowOpticalCenter": (False, "p_bool", False),
        b"ShowAzimut": (True, "p_bool", False),
        b"ShowTimeCode": (False, "p_bool", False),
        b"ShowAudio": (False, "p_bool", False),
        b"AudioColor": ((0.0, 1.0, 0.0), "p_vector_3d", False),  # Yep, vector3d, not corlorgb… :cry:
        b"NearPlane": (10.0, "p_double", False),
        b"FarPlane": (4000.0, "p_double", False),
        b"AutoComputeClipPanes": (False, "p_bool", False),
        b"ViewCameraToLookAt": (True, "p_bool", False),
        b"ViewFrustumNearFarPlane": (False, "p_bool", False),
        b"ViewFrustumBackPlaneMode": (2, "p_enum", False),  # 2 = show back plane if texture added.
        b"BackPlaneDistance": (4000.0, "p_number", True),
        b"BackPlaneDistanceMode": (1, "p_enum", False),  # 1 = relative to camera.
        b"ViewFrustumFrontPlaneMode": (2, "p_enum", False),  # 2 = show front plane if texture added.
        b"FrontPlaneDistance": (10.0, "p_number", True),
        b"FrontPlaneDistanceMode": (1, "p_enum", False),  # 1 = relative to camera.
        b"LockMode": (False, "p_bool", False),
        b"LockInterestNavigation": (False, "p_bool", False),
        # BackPlate... properties **arggggg!**
        b"FitImage": (False, "p_bool", False),
        b"Crop": (False, "p_bool", False),
        b"Center": (True, "p_bool", False),
        b"KeepRatio": (True, "p_bool", False),
        # End of BackPlate...
        b"BackgroundAlphaTreshold": (0.5, "p_double", False),
        b"ShowBackplate": (True, "p_bool", False),
        b"BackPlaneOffsetX": (0.0, "p_number", True),
        b"BackPlaneOffsetY": (0.0, "p_number", True),
        b"BackPlaneRotation": (0.0, "p_number", True),
        b"BackPlaneScaleX": (1.0, "p_number", True),
        b"BackPlaneScaleY": (1.0, "p_number", True),
        b"Background Texture": (None, "p_object", False),
        b"FrontPlateFitImage": (True, "p_bool", False),
        b"FrontPlateCrop": (False, "p_bool", False),
        b"FrontPlateCenter": (True, "p_bool", False),
        b"FrontPlateKeepRatio": (True, "p_bool", False),
        b"Foreground Opacity": (1.0, "p_double", False),
        b"ShowFrontplate": (True, "p_bool", False),
        b"FrontPlaneOffsetX": (0.0, "p_number", True),
        b"FrontPlaneOffsetY": (0.0, "p_number", True),
        b"FrontPlaneRotation": (0.0, "p_number", True),
        b"FrontPlaneScaleX": (1.0, "p_number", True),
        b"FrontPlaneScaleY": (1.0, "p_number", True),
        b"Foreground Texture": (None, "p_object", False),
        b"DisplaySafeArea": (False, "p_bool", False),
        b"DisplaySafeAreaOnRender": (False, "p_bool", False),
        b"SafeAreaDisplayStyle": (1, "p_enum", False),  # 1 = rounded corners.
        b"SafeAreaAspectRatio": (1.3333333333333333, "p_double", False),
        b"Use2DMagnifierZoom": (False, "p_bool", False),
        b"2D Magnifier Zoom": (100.0, "p_number", True),
        b"2D Magnifier X": (50.0, "p_number", True),
        b"2D Magnifier Y": (50.0, "p_number", True),
        b"CameraProjectionType": (0, "p_enum", False),  # 0 = perspective, 1 = orthogonal.
        b"OrthoZoom": (1.0, "p_double", False),
        b"UseRealTimeDOFAndAA": (False, "p_bool", False),
        b"UseDepthOfField": (False, "p_bool", False),
        b"FocusSource": (0, "p_enum", False),  # 0 = camera interest, 1 = distance from camera interest.
        b"FocusAngle": (3.5, "p_double", False),  # ???
        b"FocusDistance": (200.0, "p_double", False),
        b"UseAntialiasing": (False, "p_bool", False),
        b"AntialiasingIntensity": (0.77777, "p_double", False),
        b"AntialiasingMethod": (0, "p_enum", False),  # 0 = oversampling, 1 = hardware.
        b"UseAccumulationBuffer": (False, "p_bool", False),
        b"FrameSamplingCount": (7, "p_integer", False),
        b"FrameSamplingType": (1, "p_enum", False),  # 0 = uniform, 1 = stochastic.
    }
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"NodeAttribute", b"FbxCamera", props, nbr_users, [False])


def fbx_template_def_bone(scene, settings, override_defaults=None, nbr_users=0):
    props = {}
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"NodeAttribute", b"LimbNode", props, nbr_users, [False])


def fbx_template_def_geometry(scene, settings, override_defaults=None, nbr_users=0):
    props = {
        b"Color": ((0.8, 0.8, 0.8), "p_color_rgb", False),
        b"BBoxMin": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"BBoxMax": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"Primary Visibility": (True, "p_bool", False),
        b"Casts Shadows": (True, "p_bool", False),
        b"Receive Shadows": (True, "p_bool", False),
    }
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"Geometry", b"FbxMesh", props, nbr_users, [False])


def fbx_template_def_material(scene, settings, override_defaults=None, nbr_users=0):
    # WIP...
    props = {
        b"ShadingModel": ("Phong", "p_string", False),
        b"MultiLayer": (False, "p_bool", False),
        # Lambert-specific.
        b"EmissiveColor": ((0.0, 0.0, 0.0), "p_color", True),
        b"EmissiveFactor": (1.0, "p_number", True),
        b"AmbientColor": ((0.2, 0.2, 0.2), "p_color", True),
        b"AmbientFactor": (1.0, "p_number", True),
        b"DiffuseColor": ((0.8, 0.8, 0.8), "p_color", True),
        b"DiffuseFactor": (1.0, "p_number", True),
        b"TransparentColor": ((0.0, 0.0, 0.0), "p_color", True),
        b"TransparencyFactor": (0.0, "p_number", True),
        b"Opacity": (1.0, "p_number", True),
        b"NormalMap": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"Bump": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"BumpFactor": (1.0, "p_double", False),
        b"DisplacementColor": ((0.0, 0.0, 0.0), "p_color_rgb", False),
        b"DisplacementFactor": (1.0, "p_double", False),
        b"VectorDisplacementColor": ((0.0, 0.0, 0.0), "p_color_rgb", False),
        b"VectorDisplacementFactor": (1.0, "p_double", False),
        # Phong-specific.
        b"SpecularColor": ((0.2, 0.2, 0.2), "p_color", True),
        b"SpecularFactor": (1.0, "p_number", True),
        # Not sure about the name, importer uses this (but ShininessExponent for tex prop name!)
        # And in fbx exported by sdk, you have one in template, the other in actual material!!! :/
        # For now, using both.
        b"Shininess": (20.0, "p_number", True),
        b"ShininessExponent": (20.0, "p_number", True),
        b"ReflectionColor": ((0.0, 0.0, 0.0), "p_color", True),
        b"ReflectionFactor": (1.0, "p_number", True),
    }
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"Material", b"FbxSurfacePhong", props, nbr_users, [False])


def fbx_template_def_texture_file(scene, settings, override_defaults=None, nbr_users=0):
    # WIP...
    # XXX Not sure about all names!
    props = {
        b"TextureTypeUse": (0, "p_enum", False),  # Standard.
        b"AlphaSource": (2, "p_enum", False),  # Black (i.e. texture's alpha), XXX name guessed!.
        b"Texture alpha": (1.0, "p_double", False),
        b"PremultiplyAlpha": (True, "p_bool", False),
        b"CurrentTextureBlendMode": (1, "p_enum", False),  # Additive...
        b"CurrentMappingType": (0, "p_enum", False),  # UV.
        b"UVSet": ("default", "p_string", False),  # UVMap name.
        b"WrapModeU": (0, "p_enum", False),  # Repeat.
        b"WrapModeV": (0, "p_enum", False),  # Repeat.
        b"UVSwap": (False, "p_bool", False),
        b"Translation": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"Rotation": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"Scaling": ((1.0, 1.0, 1.0), "p_vector_3d", False),
        b"TextureRotationPivot": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        b"TextureScalingPivot": ((0.0, 0.0, 0.0), "p_vector_3d", False),
        # Not sure about those two...
        b"UseMaterial": (False, "p_bool", False),
        b"UseMipMap": (False, "p_bool", False),
    }
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"Texture", b"FbxFileTexture", props, nbr_users, [False])


def fbx_template_def_video(scene, settings, override_defaults=None, nbr_users=0):
    # WIP...
    props = {
        # All pictures.
        b"Width": (0, "p_integer", False),
        b"Height": (0, "p_integer", False),
        b"Path": ("", "p_string_url", False),
        b"AccessMode": (0, "p_enum", False),  # Disk (0=Disk, 1=Mem, 2=DiskAsync).
        # All videos.
        b"StartFrame": (0, "p_integer", False),
        b"StopFrame": (0, "p_integer", False),
        b"Offset": (0, "p_timestamp", False),
        b"PlaySpeed": (0.0, "p_double", False),
        b"FreeRunning": (False, "p_bool", False),
        b"Loop": (False, "p_bool", False),
        b"InterlaceMode": (0, "p_enum", False),  # None, i.e. progressive.
        # Image sequences.
        b"ImageSequence": (False, "p_bool", False),
        b"ImageSequenceOffset": (0, "p_integer", False),
        b"FrameRate": (0.0, "p_double", False),
        b"LastFrame": (0, "p_integer", False),
    }
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"Video", b"FbxVideo", props, nbr_users, [False])


def fbx_template_def_pose(scene, settings, override_defaults=None, nbr_users=0):
    props = {}
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"Pose", b"", props, nbr_users, [False])


def fbx_template_def_deformer(scene, settings, override_defaults=None, nbr_users=0):
    props = {}
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"Deformer", b"", props, nbr_users, [False])


def fbx_template_def_animstack(scene, settings, override_defaults=None, nbr_users=0):
    props = {
        b"Description": ("", "p_string", False),
        b"LocalStart": (0, "p_timestamp", False),
        b"LocalStop": (0, "p_timestamp", False),
        b"ReferenceStart": (0, "p_timestamp", False),
        b"ReferenceStop": (0, "p_timestamp", False),
    }
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"AnimationStack", b"FbxAnimStack", props, nbr_users, [False])


def fbx_template_def_animlayer(scene, settings, override_defaults=None, nbr_users=0):
    props = {
        b"Weight": (100.0, "p_number", True),
        b"Mute": (False, "p_bool", False),
        b"Solo": (False, "p_bool", False),
        b"Lock": (False, "p_bool", False),
        b"Color": ((0.8, 0.8, 0.8), "p_color_rgb", False),
        b"BlendMode": (0, "p_enum", False),
        b"RotationAccumulationMode": (0, "p_enum", False),
        b"ScaleAccumulationMode": (0, "p_enum", False),
        b"BlendModeBypass": (0, "p_ulonglong", False),
    }
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"AnimationLayer", b"FbxAnimLayer", props, nbr_users, [False])


def fbx_template_def_animcurvenode(scene, settings, override_defaults=None, nbr_users=0):
    props = {
        FBX_ANIM_PROPSGROUP_NAME.encode(): (None, "p_compound", False),
    }
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"AnimationCurveNode", b"FbxAnimCurveNode", props, nbr_users, [False])


def fbx_template_def_animcurve(scene, settings, override_defaults=None, nbr_users=0):
    props = {}
    if override_defaults is not None:
        props.update(override_defaults)
    return FBXTemplate(b"AnimationCurve", b"", props, nbr_users, [False])


# ##### Generators for connection elements. #####

def elem_connection(elem, c_type, uid_src, uid_dst, prop_dst=None):
    e = elem_data_single_string(elem, b"C", c_type)
    e.add_int64(uid_src)
    e.add_int64(uid_dst)
    if prop_dst is not None:
        e.add_string(prop_dst)


# ##### FBX objects generators. #####

def fbx_data_element_custom_properties(props, bid):
    """
    Store custom properties of blender ID bid (any mapping-like object, in fact) into FBX properties props.
    """
    items = bid.items()

    if not items:
        return

    rna_properties = {prop.identifier for prop in bid.bl_rna.properties if prop.is_runtime}

    for k, v in items:
        if k in rna_properties:
            continue

        list_val = getattr(v, "to_list", lambda: None)()

        if isinstance(v, str):
            elem_props_set(props, "p_string", k.encode(), v, custom=True)
        elif isinstance(v, int):
            elem_props_set(props, "p_integer", k.encode(), v, custom=True)
        elif isinstance(v, float):
            elem_props_set(props, "p_double", k.encode(), v, custom=True)
        elif list_val:
            if len(list_val) == 3:
                elem_props_set(props, "p_vector", k.encode(), list_val, custom=True)
            else:
                elem_props_set(props, "p_string", k.encode(), str(list_val), custom=True)
        else:
            elem_props_set(props, "p_string", k.encode(), str(v), custom=True)


def fbx_data_empty_elements(root, empty, scene_data):
    """
    Write the Empty data block (you can control its FBX datatype with the 'fbx_type' string custom property).
    """
    empty_key = scene_data.data_empties[empty]

    null = elem_data_single_int64(root, b"NodeAttribute", get_fbx_uuid_from_key(empty_key))
    null.add_string(fbx_name_class(empty.name.encode(), b"NodeAttribute"))
    val = empty.bdata.get('fbx_type', None)
    null.add_string(val.encode() if val and isinstance(val, str) else b"Null")

    elem_data_single_string(null, b"TypeFlags", b"Null")

    tmpl = elem_props_template_init(scene_data.templates, b"Null")
    props = elem_properties(null)
    elem_props_template_finalize(tmpl, props)

    # No custom properties, already saved with object (Model).


def fbx_data_light_elements(root, lamp, scene_data):
    """
    Write the Lamp data block.
    """
    gscale = scene_data.settings.global_scale

    light_key = scene_data.data_lights[lamp]
    do_light = True
    decay_type = FBX_LIGHT_DECAY_TYPES['CONSTANT']
    do_shadow = False
    shadow_color = Vector((0.0, 0.0, 0.0))
    if lamp.type not in {'HEMI'}:
        if lamp.type not in {'SUN', 'AREA'}:
            decay_type = FBX_LIGHT_DECAY_TYPES[lamp.falloff_type]
        do_light = True
        do_shadow = lamp.use_shadow
        shadow_color = lamp.shadow_color

    light = elem_data_single_int64(root, b"NodeAttribute", get_fbx_uuid_from_key(light_key))
    light.add_string(fbx_name_class(lamp.name.encode(), b"NodeAttribute"))
    light.add_string(b"Light")

    elem_data_single_int32(light, b"GeometryVersion", FBX_GEOMETRY_VERSION)  # Sic...

    tmpl = elem_props_template_init(scene_data.templates, b"Light")
    props = elem_properties(light)
    elem_props_template_set(tmpl, props, "p_enum", b"LightType", FBX_LIGHT_TYPES[lamp.type])
    elem_props_template_set(tmpl, props, "p_bool", b"CastLight", do_light)
    elem_props_template_set(tmpl, props, "p_color", b"Color", lamp.color)
    elem_props_template_set(tmpl, props, "p_number", b"Intensity", lamp.energy * 100.0)
    elem_props_template_set(tmpl, props, "p_enum", b"DecayType", decay_type)
    elem_props_template_set(tmpl, props, "p_double", b"DecayStart", lamp.distance * gscale)
    elem_props_template_set(tmpl, props, "p_bool", b"CastShadows", do_shadow)
    elem_props_template_set(tmpl, props, "p_color", b"ShadowColor", shadow_color)
    if lamp.type in {'SPOT'}:
        elem_props_template_set(tmpl, props, "p_double", b"OuterAngle", math.degrees(lamp.spot_size))
        elem_props_template_set(tmpl, props, "p_double", b"InnerAngle",
                                math.degrees(lamp.spot_size * (1.0 - lamp.spot_blend)))
    elem_props_template_finalize(tmpl, props)

    # Custom properties.
    if scene_data.settings.use_custom_props:
        fbx_data_element_custom_properties(props, lamp)


def fbx_data_camera_elements(root, cam_obj, scene_data):
    """
    Write the Camera data blocks.
    """
    gscale = scene_data.settings.global_scale

    cam = cam_obj.bdata
    cam_data = cam.data
    cam_key = scene_data.data_cameras[cam_obj]

    # Real data now, good old camera!
    # Object transform info.
    loc, rot, scale, matrix, matrix_rot = cam_obj.fbx_object_tx(scene_data)
    up = matrix_rot @ Vector((0.0, 1.0, 0.0))
    to = matrix_rot @ Vector((0.0, 0.0, -1.0))
    # Render settings.
    # TODO We could export much more...
    render = scene_data.scene.render
    width = render.resolution_x
    height = render.resolution_y
    aspect = width / height
    # Film width & height from mm to inches
    filmwidth = convert_mm_to_inch(cam_data.sensor_width)
    filmheight = convert_mm_to_inch(cam_data.sensor_height)
    filmaspect = filmwidth / filmheight
    # Film offset
    offsetx = filmwidth * cam_data.shift_x
    offsety = filmaspect * filmheight * cam_data.shift_y

    cam = elem_data_single_int64(root, b"NodeAttribute", get_fbx_uuid_from_key(cam_key))
    cam.add_string(fbx_name_class(cam_data.name.encode(), b"NodeAttribute"))
    cam.add_string(b"Camera")

    tmpl = elem_props_template_init(scene_data.templates, b"Camera")
    props = elem_properties(cam)

    elem_props_template_set(tmpl, props, "p_vector", b"Position", loc)
    elem_props_template_set(tmpl, props, "p_vector", b"UpVector", up)
    elem_props_template_set(tmpl, props, "p_vector", b"InterestPosition", loc + to)  # Point, not vector!
    # Should we use world value?
    elem_props_template_set(tmpl, props, "p_color", b"BackgroundColor", (0.0, 0.0, 0.0))
    elem_props_template_set(tmpl, props, "p_bool", b"DisplayTurnTableIcon", True)

    elem_props_template_set(tmpl, props, "p_enum", b"AspectRatioMode", 2)  # FixedResolution
    elem_props_template_set(tmpl, props, "p_double", b"AspectWidth", float(render.resolution_x))
    elem_props_template_set(tmpl, props, "p_double", b"AspectHeight", float(render.resolution_y))
    elem_props_template_set(tmpl, props, "p_double", b"PixelAspectRatio",
                            float(render.pixel_aspect_x / render.pixel_aspect_y))

    elem_props_template_set(tmpl, props, "p_double", b"FilmWidth", filmwidth)
    elem_props_template_set(tmpl, props, "p_double", b"FilmHeight", filmheight)
    elem_props_template_set(tmpl, props, "p_double", b"FilmAspectRatio", filmaspect)
    elem_props_template_set(tmpl, props, "p_double", b"FilmOffsetX", offsetx)
    elem_props_template_set(tmpl, props, "p_double", b"FilmOffsetY", offsety)

    elem_props_template_set(tmpl, props, "p_enum", b"ApertureMode", 3)  # FocalLength.
    elem_props_template_set(tmpl, props, "p_enum", b"GateFit", 2)  # FitHorizontal.
    elem_props_template_set(tmpl, props, "p_fov", b"FieldOfView", math.degrees(cam_data.angle_x))
    elem_props_template_set(tmpl, props, "p_fov_x", b"FieldOfViewX", math.degrees(cam_data.angle_x))
    elem_props_template_set(tmpl, props, "p_fov_y", b"FieldOfViewY", math.degrees(cam_data.angle_y))
    # No need to convert to inches here...
    elem_props_template_set(tmpl, props, "p_double", b"FocalLength", cam_data.lens)
    elem_props_template_set(tmpl, props, "p_double", b"SafeAreaAspectRatio", aspect)
    # Default to perspective camera.
    elem_props_template_set(tmpl, props, "p_enum", b"CameraProjectionType", 1 if cam_data.type == 'ORTHO' else 0)
    elem_props_template_set(tmpl, props, "p_double", b"OrthoZoom", cam_data.ortho_scale)

    elem_props_template_set(tmpl, props, "p_double", b"NearPlane", cam_data.clip_start * gscale)
    elem_props_template_set(tmpl, props, "p_double", b"FarPlane", cam_data.clip_end * gscale)
    elem_props_template_set(tmpl, props, "p_enum", b"BackPlaneDistanceMode", 1)  # RelativeToCamera.
    elem_props_template_set(tmpl, props, "p_double", b"BackPlaneDistance", cam_data.clip_end * gscale)

    elem_props_template_finalize(tmpl, props)

    # Custom properties.
    if scene_data.settings.use_custom_props:
        fbx_data_element_custom_properties(props, cam_data)

    elem_data_single_string(cam, b"TypeFlags", b"Camera")
    elem_data_single_int32(cam, b"GeometryVersion", 124)  # Sic...
    elem_data_vec_float64(cam, b"Position", loc)
    elem_data_vec_float64(cam, b"Up", up)
    elem_data_vec_float64(cam, b"LookAt", to)
    elem_data_single_int32(cam, b"ShowInfoOnMoving", 1)
    elem_data_single_int32(cam, b"ShowAudio", 0)
    elem_data_vec_float64(cam, b"AudioColor", (0.0, 1.0, 0.0))
    elem_data_single_float64(cam, b"CameraOrthoZoom", 1.0)


def fbx_data_bindpose_element(root, me_obj, me, scene_data, arm_obj=None, mat_world_arm=None, bones=[]):
    """
    Helper, since bindpose are used by both meshes shape keys and armature bones...
    """
    if arm_obj is None:
        arm_obj = me_obj
    # We assume bind pose for our bones are their "Editmode" pose...
    # All matrices are expected in global (world) space.
    bindpose_key = get_blender_bindpose_key(arm_obj.bdata, me)
    fbx_pose = elem_data_single_int64(root, b"Pose", get_fbx_uuid_from_key(bindpose_key))
    fbx_pose.add_string(fbx_name_class(me.name.encode(), b"Pose"))
    fbx_pose.add_string(b"BindPose")

    elem_data_single_string(fbx_pose, b"Type", b"BindPose")
    elem_data_single_int32(fbx_pose, b"Version", FBX_POSE_BIND_VERSION)
    elem_data_single_int32(fbx_pose, b"NbPoseNodes", 1 + (1 if (arm_obj != me_obj) else 0) + len(bones))

    # First node is mesh/object.
    mat_world_obj = me_obj.fbx_object_matrix(scene_data, global_space=True)
    fbx_posenode = elem_empty(fbx_pose, b"PoseNode")
    elem_data_single_int64(fbx_posenode, b"Node", me_obj.fbx_uuid)
    elem_data_single_float64_array(fbx_posenode, b"Matrix", matrix4_to_array(mat_world_obj))
    # Second node is armature object itself.
    if arm_obj != me_obj:
        fbx_posenode = elem_empty(fbx_pose, b"PoseNode")
        elem_data_single_int64(fbx_posenode, b"Node", arm_obj.fbx_uuid)
        elem_data_single_float64_array(fbx_posenode, b"Matrix", matrix4_to_array(mat_world_arm))
    # And all bones of armature!
    mat_world_bones = {}
    for bo_obj in bones:
        bomat = bo_obj.fbx_object_matrix(scene_data, rest=True, global_space=True)
        mat_world_bones[bo_obj] = bomat
        fbx_posenode = elem_empty(fbx_pose, b"PoseNode")
        elem_data_single_int64(fbx_posenode, b"Node", bo_obj.fbx_uuid)
        elem_data_single_float64_array(fbx_posenode, b"Matrix", matrix4_to_array(bomat))

    return mat_world_obj, mat_world_bones


def fbx_data_mesh_shapes_elements(root, me_obj, me, scene_data, fbx_me_tmpl, fbx_me_props):
    """
    Write shape keys related data.
    """
    if me not in scene_data.data_deformers_shape:
        return

    write_normals = True  # scene_data.settings.mesh_smooth_type in {'OFF'}

    # First, write the geometry data itself (i.e. shapes).
    _me_key, shape_key, shapes = scene_data.data_deformers_shape[me]

    channels = []

    for shape, (channel_key, geom_key, shape_verts_co, shape_verts_idx) in shapes.items():
        # Use vgroups as weights, if defined.
        if shape.vertex_group and shape.vertex_group in me_obj.bdata.vertex_groups:
            shape_verts_weights = [0.0] * (len(shape_verts_co) // 3)
            vg_idx = me_obj.bdata.vertex_groups[shape.vertex_group].index
            for sk_idx, v_idx in enumerate(shape_verts_idx):
                for vg in me.vertices[v_idx].groups:
                    if vg.group == vg_idx:
                        shape_verts_weights[sk_idx] = vg.weight * 100.0
        else:
            shape_verts_weights = [100.0] * (len(shape_verts_co) // 3)
        channels.append((channel_key, shape, shape_verts_weights))

        geom = elem_data_single_int64(root, b"Geometry", get_fbx_uuid_from_key(geom_key))
        geom.add_string(fbx_name_class(shape.name.encode(), b"Geometry"))
        geom.add_string(b"Shape")

        tmpl = elem_props_template_init(scene_data.templates, b"Geometry")
        props = elem_properties(geom)
        elem_props_template_finalize(tmpl, props)

        elem_data_single_int32(geom, b"Version", FBX_GEOMETRY_SHAPE_VERSION)

        elem_data_single_int32_array(geom, b"Indexes", shape_verts_idx)
        elem_data_single_float64_array(geom, b"Vertices", shape_verts_co)
        if write_normals:
            elem_data_single_float64_array(geom, b"Normals", [0.0] * len(shape_verts_co))

    # Yiha! BindPose for shapekeys too! Dodecasigh...
    # XXX Not sure yet whether several bindposes on same mesh are allowed, or not... :/
    fbx_data_bindpose_element(root, me_obj, me, scene_data)

    # ...and now, the deformers stuff.
    fbx_shape = elem_data_single_int64(root, b"Deformer", get_fbx_uuid_from_key(shape_key))
    fbx_shape.add_string(fbx_name_class(me.name.encode(), b"Deformer"))
    fbx_shape.add_string(b"BlendShape")

    elem_data_single_int32(fbx_shape, b"Version", FBX_DEFORMER_SHAPE_VERSION)

    for channel_key, shape, shape_verts_weights in channels:
        fbx_channel = elem_data_single_int64(root, b"Deformer", get_fbx_uuid_from_key(channel_key))
        fbx_channel.add_string(fbx_name_class(shape.name.encode(), b"SubDeformer"))
        fbx_channel.add_string(b"BlendShapeChannel")

        elem_data_single_int32(fbx_channel, b"Version", FBX_DEFORMER_SHAPECHANNEL_VERSION)
        elem_data_single_float64(fbx_channel, b"DeformPercent", shape.value * 100.0)  # Percents...
        elem_data_single_float64_array(fbx_channel, b"FullWeights", shape_verts_weights)

        # *WHY* add this in linked mesh properties too? *cry*
        # No idea whether it’s percent here too, or more usual factor (assume percentage for now) :/
        elem_props_template_set(fbx_me_tmpl, fbx_me_props, "p_number", shape.name.encode(), shape.value * 100.0,
                                animatable=True)


def fbx_data_mesh_elements(root, me_obj, scene_data, done_meshes):
    """
    Write the Mesh (Geometry) data block.
    """
    # Ugly helper... :/
    def _infinite_gen(val):
        while 1:
            yield val

    me_key, me, _free = scene_data.data_meshes[me_obj]

    # In case of multiple instances of same mesh, only write it once!
    if me_key in done_meshes:
        return

    # No gscale/gmat here, all data are supposed to be in object space.
    smooth_type = scene_data.settings.mesh_smooth_type
    write_normals = True  # smooth_type in {'OFF'}

    do_bake_space_transform = me_obj.use_bake_space_transform(scene_data)

    # Vertices are in object space, but we are post-multiplying all transforms with the inverse of the
    # global matrix, so we need to apply the global matrix to the vertices to get the correct result.
    geom_mat_co = scene_data.settings.global_matrix if do_bake_space_transform else None
    # We need to apply the inverse transpose of the global matrix when transforming normals.
    geom_mat_no = Matrix(scene_data.settings.global_matrix_inv_transposed) if do_bake_space_transform else None
    if geom_mat_no is not None:
        # Remove translation & scaling!
        geom_mat_no.translation = Vector()
        geom_mat_no.normalize()

    geom = elem_data_single_int64(root, b"Geometry", get_fbx_uuid_from_key(me_key))
    geom.add_string(fbx_name_class(me.name.encode(), b"Geometry"))
    geom.add_string(b"Mesh")

    tmpl = elem_props_template_init(scene_data.templates, b"Geometry")
    props = elem_properties(geom)

    # Custom properties.
    if scene_data.settings.use_custom_props:
        fbx_data_element_custom_properties(props, me)

    # Subdivision levels. Take them from the first found subsurf modifier from the
    # first object that has the mesh. Write crease information if the object has
    # and subsurf modifier.
    write_crease = False
    if scene_data.settings.use_subsurf:
        last_subsurf = None
        for mod in me_obj.bdata.modifiers:
            if not (mod.show_render or mod.show_viewport):
                continue
            if mod.type == 'SUBSURF' and mod.subdivision_type == 'CATMULL_CLARK':
                last_subsurf = mod

        if last_subsurf:
            elem_data_single_int32(geom, b"Smoothness", 2) # Display control mesh and smoothed
            if last_subsurf.boundary_smooth == "PRESERVE_CORNERS":
                elem_data_single_int32(geom, b"BoundaryRule", 2) # CreaseAll
            else:
                elem_data_single_int32(geom, b"BoundaryRule", 1) # CreaseEdge
            elem_data_single_int32(geom, b"PreviewDivisionLevels", last_subsurf.levels)
            elem_data_single_int32(geom, b"RenderDivisionLevels", last_subsurf.render_levels)

            elem_data_single_int32(geom, b"PreserveBorders", 0)
            elem_data_single_int32(geom, b"PreserveHardEdges", 0)
            elem_data_single_int32(geom, b"PropagateEdgeHardness", 0)

            write_crease = last_subsurf.use_creases

    elem_data_single_int32(geom, b"GeometryVersion", FBX_GEOMETRY_VERSION)

    # Vertex cos.
    t_co = array.array(data_types.ARRAY_FLOAT64, (0.0,)) * len(me.vertices) * 3
    me.vertices.foreach_get("co", t_co)
    elem_data_single_float64_array(geom, b"Vertices", chain(*vcos_transformed_gen(t_co, geom_mat_co)))
    del t_co

    # Polygon indices.
    #
    # We do loose edges as two-vertices faces, if enabled...
    #
    # Note we have to process Edges in the same time, as they are based on poly's loops...
    loop_nbr = len(me.loops)
    t_pvi = array.array(data_types.ARRAY_INT32, (0,)) * loop_nbr
    t_ls = [None] * len(me.polygons)

    me.loops.foreach_get("vertex_index", t_pvi)
    me.polygons.foreach_get("loop_start", t_ls)

    # Add "fake" faces for loose edges.
    if scene_data.settings.use_mesh_edges:
        t_le = tuple(e.vertices for e in me.edges if e.is_loose)
        t_pvi.extend(chain(*t_le))
        t_ls.extend(range(loop_nbr, loop_nbr + len(t_le), 2))
        del t_le

    # Edges...
    # Note: Edges are represented as a loop here: each edge uses a single index, which refers to the polygon array.
    #       The edge is made by the vertex indexed py this polygon's point and the next one on the same polygon.
    #       Advantage: Only one index per edge.
    #       Drawback: Only polygon's edges can be represented (that's why we have to add fake two-verts polygons
    #                 for loose edges).
    #       We also have to store a mapping from real edges to their indices in this array, for edge-mapped data
    #       (like e.g. crease).
    t_eli = array.array(data_types.ARRAY_INT32)
    edges_map = {}
    edges_nbr = 0
    if t_ls and t_pvi:
        t_ls = set(t_ls)
        todo_edges = [None] * len(me.edges) * 2
        # Sigh, cannot access edge.key through foreach_get... :/
        me.edges.foreach_get("vertices", todo_edges)
        todo_edges = set((v1, v2) if v1 < v2 else (v2, v1) for v1, v2 in zip(*(iter(todo_edges),) * 2))

        li = 0
        vi = vi_start = t_pvi[0]
        for li_next, vi_next in enumerate(t_pvi[1:] + t_pvi[:1], start=1):
            if li_next in t_ls:  # End of a poly's loop.
                vi2 = vi_start
                vi_start = vi_next
            else:
                vi2 = vi_next

            e_key = (vi, vi2) if vi < vi2 else (vi2, vi)
            if e_key in todo_edges:
                t_eli.append(li)
                todo_edges.remove(e_key)
                edges_map[e_key] = edges_nbr
                edges_nbr += 1

            vi = vi_next
            li = li_next
    # End of edges!

    # We have to ^-1 last index of each loop.
    for ls in t_ls:
        t_pvi[ls - 1] ^= -1

    # And finally we can write data!
    elem_data_single_int32_array(geom, b"PolygonVertexIndex", t_pvi)
    elem_data_single_int32_array(geom, b"Edges", t_eli)
    del t_pvi
    del t_ls
    del t_eli

    # And now, layers!

    # Smoothing.
    if smooth_type in {'FACE', 'EDGE'}:
        t_ps = None
        _map = b""
        if smooth_type == 'FACE':
            t_ps = array.array(data_types.ARRAY_INT32, (0,)) * len(me.polygons)
            me.polygons.foreach_get("use_smooth", t_ps)
            _map = b"ByPolygon"
        else:  # EDGE
            # Write Edge Smoothing.
            # Note edge is sharp also if it's used by more than two faces, or one of its faces is flat.
            t_ps = array.array(data_types.ARRAY_INT32, (0,)) * edges_nbr
            sharp_edges = set()
            temp_sharp_edges = {}
            for p in me.polygons:
                if not p.use_smooth:
                    sharp_edges.update(p.edge_keys)
                    continue
                for k in p.edge_keys:
                    if temp_sharp_edges.setdefault(k, 0) > 1:
                        sharp_edges.add(k)
                    else:
                        temp_sharp_edges[k] += 1
            del temp_sharp_edges
            for e in me.edges:
                if e.key not in edges_map:
                    continue  # Only loose edges, in theory!
                t_ps[edges_map[e.key]] = not (e.use_edge_sharp or (e.key in sharp_edges))