export_fbx_bin.py

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#
#  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
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#  but WITHOUT ANY WARRANTY; without even the implied warranty of
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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 collections import OrderedDict
from itertools import zip_longest, chain

import bpy
import bpy_extras
from mathutils import Vector, Matrix

from . import encode_bin, data_types
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_VCOLOR_VERSION, FBX_GEOMETRY_UV_VERSION,
    FBX_GEOMETRY_MATERIAL_VERSION, FBX_GEOMETRY_LAYER_VERSION,
    FBX_POSE_BIND_VERSION, FBX_DEFORMER_SKIN_VERSION, FBX_DEFORMER_CLUSTER_VERSION,
    FBX_MATERIAL_VERSION, FBX_TEXTURE_VERSION,
    FBX_ANIM_KEY_VERSION,
    FBX_KTIME,
    BLENDER_OTHER_OBJECT_TYPES, BLENDER_OBJECT_TYPES_MESHLIKE,
    FBX_LIGHT_TYPES, FBX_LIGHT_DECAY_TYPES,
    RIGHT_HAND_AXES, FBX_FRAMERATES,
    # Miscellaneous utils.
    units_convert, units_convert_iter, matrix_to_array, similar_values,
    # UUID from key.
    get_fbx_uuid_from_key,
    # Key generators.
    get_blenderID_key, get_blenderID_name,
    get_blender_empty_key, get_blender_bone_key,
    get_blender_armature_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,
    # 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,
    # Objects.
    ObjectWrapper, fbx_name_class,
    # Top level.
    FBXSettingsMedia, FBXSettings, FBXData,
)

##### 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 = OrderedDict()
    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 = OrderedDict((
        # 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 = OrderedDict((
        (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 = OrderedDict((
        (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 = OrderedDict((
        (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, "p_double", False)),
        (b"AspectHeight", (200, "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 = OrderedDict()
    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 = OrderedDict((
        (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 = OrderedDict((
        (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 = OrderedDict((
        (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", (b"default", "p_string", False)),
        (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 = OrderedDict((
        # 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 = OrderedDict()
    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 = OrderedDict()
    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 = OrderedDict((
        (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 = OrderedDict((
        (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 = OrderedDict((
        (b"d", (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 = OrderedDict()
    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.
    """
    for k, v in bid.items():
        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)
        if isinstance(v, float):
            elem_props_set(props, "p_double", k.encode(), v, custom=True)


def fbx_data_empty_elements(root, empty, scene_data):
    """
    Write the Empty data block.
    """
    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"))
    null.add_string(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_lamp_elements(root, lamp, scene_data):
    """
    Write the Lamp data block.
    """
    gscale = scene_data.settings.global_scale

    lamp_key = scene_data.data_lamps[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 = (not lamp.use_only_shadow) and (lamp.use_specular or lamp.use_diffuse)
        do_shadow = lamp.shadow_method not in {'NOSHADOW'}
        shadow_color = lamp.shadow_color

    light = elem_data_single_int64(root, b"NodeAttribute", get_fbx_uuid_from_key(lamp_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_properties:
        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 = units_convert(cam_data.sensor_width, "millimeter", "inch")
    filmheight = units_convert(cam_data.sensor_height, "millimeter", "inch")
    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_double", b"AspectRatioMode", 1)  # FixedRatio
    elem_props_template_set(tmpl, props, "p_double", b"AspectWidth", float(r.resolution_x))
    elem_props_template_set(tmpl, props, "p_double", b"AspectHeight", float(r.resolution_y))
    elem_props_template_set(tmpl, props, "p_double", b"PixelAspectRatio", float(r.pixel_aspect_x / r.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)

    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_properties:
        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_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

    do_bake_space_transform = ObjectWrapper(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)

    elem_props_template_finalize(tmpl, props)

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

    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)
    if geom_mat_co is not None:
        def _vcos_transformed_gen(raw_cos, m=None):
            # Note: we could most likely get much better performances with numpy, but will leave this as TODO for now.
            return chain(*(m * Vector(v) for v in zip(*(iter(raw_cos),) * 3)))
        t_co = _vcos_transformed_gen(t_co, geom_mat_co)
    elem_data_single_float64_array(geom, b"Vertices", t_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
        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.
            t_ps = array.array(data_types.ARRAY_INT32, (0,)) * edges_nbr
            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
            _map = b"ByEdge"
        lay_smooth = elem_data_single_int32(geom, b"LayerElementSmoothing", 0)
        elem_data_single_int32(lay_smooth, b"Version", FBX_GEOMETRY_SMOOTHING_VERSION)
        elem_data_single_string(lay_smooth, b"Name", b"")
        elem_data_single_string(lay_smooth, b"MappingInformationType", _map)
        elem_data_single_string(lay_smooth, b"ReferenceInformationType", b"Direct")
        elem_data_single_int32_array(lay_smooth, b"Smoothing", t_ps)  # Sight, int32 for bool...
        del t_ps

    # TODO: Edge crease (LayerElementCrease).

    # And we are done with edges!
    del edges_map

    # Loop normals.
    # NOTE: this is not supported by importer currently.
    # XXX Official docs says normals should use IndexToDirect,
    #     but this does not seem well supported by apps currently...
    me.calc_normals_split()

    def _nortuples_gen(raw_nors, m):
        # Great, now normals are also expected 4D!
        # XXX Back to 3D normals for now!
        #gen = zip(*(iter(raw_nors),) * 3 + (_infinite_gen(1.0),))
        gen = zip(*(iter(raw_nors),) * 3)
        return gen if m is None else (m * Vector(v) for v in gen)

    t_ln = array.array(data_types.ARRAY_FLOAT64, (0.0,)) * len(me.loops) * 3
    me.loops.foreach_get("normal", t_ln)
    t_ln = _nortuples_gen(t_ln, geom_mat_no)
    if 0:
        t_ln = tuple(t_ln)  # No choice... :/

        lay_nor = elem_data_single_int32(geom, b"LayerElementNormal", 0)
        elem_data_single_int32(lay_nor, b"Version", FBX_GEOMETRY_NORMAL_VERSION)
        elem_data_single_string(lay_nor, b"Name", b"")
        elem_data_single_string(lay_nor, b"MappingInformationType", b"ByPolygonVertex")
        elem_data_single_string(lay_nor, b"ReferenceInformationType", b"IndexToDirect")

        ln2idx = tuple(set(t_ln))
        elem_data_single_float64_array(lay_nor, b"Normals", chain(*ln2idx))
        # Normal weights, no idea what it is.
        #t_lnw = array.array(data_types.ARRAY_FLOAT64, (0.0,)) * len(ln2idx)
        #elem_data_single_float64_array(lay_nor, b"NormalsW", t_lnw)

        ln2idx = {nor: idx for idx, nor in enumerate(ln2idx)}
        elem_data_single_int32_array(lay_nor, b"NormalsIndex", (ln2idx[n] for n in t_ln))

        del ln2idx
        #del t_lnw
    else:
        lay_nor = elem_data_single_int32(geom, b"LayerElementNormal", 0)
        elem_data_single_int32(lay_nor, b"Version", FBX_GEOMETRY_NORMAL_VERSION)
        elem_data_single_string(lay_nor, b"Name", b"")
        elem_data_single_string(lay_nor, b"MappingInformationType", b"ByPolygonVertex")
        elem_data_single_string(lay_nor, b"ReferenceInformationType", b"Direct")
        elem_data_single_float64_array(lay_nor, b"Normals", chain(*t_ln))
        # Normal weights, no idea what it is.
        #t_ln = array.array(data_types.ARRAY_FLOAT64, (0.0,)) * len(me.loops)
        #elem_data_single_float64_array(lay_nor, b"NormalsW", t_ln)
    del t_ln

    # tspace
    tspacenumber = 0
    if scene_data.settings.use_tspace:
        tspacenumber = len(me.uv_layers)
        if tspacenumber:
            t_ln = array.array(data_types.ARRAY_FLOAT64, (0.0,)) * len(me.loops) * 3
            #t_lnw = array.array(data_types.ARRAY_FLOAT64, (0.0,)) * len(me.loops)
            for idx, uvlayer in enumerate(me.uv_layers):
                name = uvlayer.name
                me.calc_tangents(name)
                # Loop bitangents (aka binormals).
                # NOTE: this is not supported by importer currently.
                me.loops.foreach_get("bitangent", t_ln)
                lay_nor = elem_data_single_int32(geom, b"LayerElementBinormal", idx)
                elem_data_single_int32(lay_nor, b"Version", FBX_GEOMETRY_BINORMAL_VERSION)
                elem_data_single_string_unicode(lay_nor, b"Name", name)
                elem_data_single_string(lay_nor, b"MappingInformationType", b"ByPolygonVertex")
                elem_data_single_string(lay_nor, b"ReferenceInformationType", b"Direct")
                elem_data_single_float64_array(lay_nor, b"Binormals", chain(*_nortuples_gen(t_ln, geom_mat_no)))
                # Binormal weights, no idea what it is.
                #elem_data_single_float64_array(lay_nor, b"BinormalsW", t_lnw)

                # Loop tangents.
                # NOTE: this is not supported by importer currently.
                me.loops.foreach_get("tangent", t_ln)
                lay_nor = elem_data_single_int32(geom, b"LayerElementTangent", idx)
                elem_data_single_int32(lay_nor, b"Version", FBX_GEOMETRY_TANGENT_VERSION)
                elem_data_single_string_unicode(lay_nor, b"Name", name)
                elem_data_single_string(lay_nor, b"MappingInformationType", b"ByPolygonVertex")
                elem_data_single_string(lay_nor, b"ReferenceInformationType", b"Direct")
                elem_data_single_float64_array(lay_nor, b"Tangents", chain(*_nortuples_gen(t_ln, geom_mat_no)))
                # Tangent weights, no idea what it is.
                #elem_data_single_float64_array(lay_nor, b"TangentsW", t_lnw)

            del t_ln
            #del t_lnw
            me.free_tangents()

    me.free_normals_split()
    del _nortuples_gen

    # Write VertexColor Layers.
    vcolnumber = len(me.vertex_colors)
    if vcolnumber:
        def _coltuples_gen(raw_cols):
            return zip(*(iter(raw_cols),) * 3 + (_infinite_gen(1.0),))  # We need a fake alpha...

        t_lc = array.array(data_types.ARRAY_FLOAT64, (0.0,)) * len(me.loops) * 3
        for colindex, collayer in enumerate(me.vertex_colors):
            collayer.data.foreach_get("color", t_lc)
            lay_vcol = elem_data_single_int32(geom, b"LayerElementColor", colindex)
            elem_data_single_int32(lay_vcol, b"Version", FBX_GEOMETRY_VCOLOR_VERSION)
            elem_data_single_string_unicode(lay_vcol, b"Name", collayer.name)
            elem_data_single_string(lay_vcol, b"MappingInformationType", b"ByPolygonVertex")
            elem_data_single_string(lay_vcol, b"ReferenceInformationType", b"IndexToDirect")

            col2idx = tuple(set(_coltuples_gen(t_lc)))
            elem_data_single_float64_array(lay_vcol, b"Colors", chain(*col2idx))  # Flatten again...

            col2idx = {col: idx for idx, col in enumerate(col2idx)}
            elem_data_single_int32_array(lay_vcol, b"ColorIndex", (col2idx[c] for c in _coltuples_gen(t_lc)))
            del col2idx
        del t_lc
        del _coltuples_gen

    # Write UV layers.
    # Note: LayerElementTexture is deprecated since FBX 2011 - luckily!
    #       Textures are now only related to materials, in FBX!
    uvnumber = len(me.uv_layers)
    if uvnumber:
        def _uvtuples_gen(raw_uvs):
            return zip(*(iter(raw_uvs),) * 2)

        t_luv = array.array(data_types.ARRAY_FLOAT64, (0.0,)) * len(me.loops) * 2
        for uvindex, uvlayer in enumerate(me.uv_layers):
            uvlayer.data.foreach_get("uv", t_luv)
            lay_uv = elem_data_single_int32(geom, b"LayerElementUV", uvindex)
            elem_data_single_int32(lay_uv, b"Version", FBX_GEOMETRY_UV_VERSION)
            elem_data_single_string_unicode(lay_uv, b"Name", uvlayer.name)
            elem_data_single_string(lay_uv, b"MappingInformationType", b"ByPolygonVertex")
            elem_data_single_string(lay_uv, b"ReferenceInformationType", b"IndexToDirect")

            uv2idx = tuple(set(_uvtuples_gen(t_luv)))
            elem_data_single_float64_array(lay_uv, b"UV", chain(*uv2idx))  # Flatten again...

            uv2idx = {uv: idx for idx, uv in enumerate(uv2idx)}
            elem_data_single_int32_array(lay_uv, b"UVIndex", (uv2idx[uv] for uv in _uvtuples_gen(t_luv)))
            del uv2idx
        del t_luv
        del _uvtuples_gen

    # Face's materials.
    me_fbxmats_idx = None
    if me in scene_data.mesh_mat_indices:
        me_fbxmats_idx = scene_data.mesh_mat_indices[me]
        me_blmats = me.materials
        if me_fbxmats_idx and me_blmats:
            lay_mat = elem_data_single_int32(geom, b"LayerElementMaterial", 0)
            elem_data_single_int32(lay_mat, b"Version", FBX_GEOMETRY_MATERIAL_VERSION)
            elem_data_single_string(lay_mat, b"Name", b"")
            nbr_mats = len(me_fbxmats_idx)
            if nbr_mats > 1:
                t_pm = array.array(data_types.ARRAY_INT32, (0,)) * len(me.polygons)
                me.polygons.foreach_get("material_index", t_pm)

                # We have to validate mat indices, and map them to FBX indices.
                blmats_to_fbxmats_idxs = [me_fbxmats_idx[m] for m in me_blmats]
                mat_idx_limit = len(blmats_to_fbxmats_idxs)
                def_mat = blmats_to_fbxmats_idxs[0]
                _gen = (blmats_to_fbxmats_idxs[m] if m < mat_idx_limit else def_mat for m in t_pm)
                t_pm = array.array(data_types.ARRAY_INT32, _gen)

                elem_data_single_string(lay_mat, b"MappingInformationType", b"ByPolygon")
                # XXX Logically, should be "Direct" reference type, since we do not have any index array, and have one
                #     value per polygon...
                #     But looks like FBX expects it to be IndexToDirect here (maybe because materials are already
                #     indices??? *sigh*).
                elem_data_single_string(lay_mat, b"ReferenceInformationType", b"IndexToDirect")
                elem_data_single_int32_array(lay_mat, b"Materials", t_pm)
                del t_pm
            else:
                elem_data_single_string(lay_mat, b"MappingInformationType", b"AllSame")
                elem_data_single_string(lay_mat, b"ReferenceInformationType", b"IndexToDirect")
                elem_data_single_int32_array(lay_mat, b"Materials", [0])

    # And the "layer TOC"...

    layer = elem_data_single_int32(geom, b"Layer", 0)
    elem_data_single_int32(layer, b"Version", FBX_GEOMETRY_LAYER_VERSION)
    lay_nor = elem_empty(layer, b"LayerElement")
    elem_data_single_string(lay_nor, b"Type", b"LayerElementNormal")
    elem_data_single_int32(lay_nor, b"TypedIndex", 0)
    if tspacenumber: