import_fbx.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.
#
#  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.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
# ##### END GPL LICENSE BLOCK #####

# <pep8 compliant>

# Script copyright (C) Blender Foundation

# FBX 7.1.0 -> 7.4.0 loader for Blender

# Not totally pep8 compliant.
#   pep8 import_fbx.py --ignore=E501,E123,E702,E125

if "bpy" in locals():
    import importlib
    if "parse_fbx" in locals():
        importlib.reload(parse_fbx)

import bpy

# -----
# Utils
from . import parse_fbx, fbx_utils

from .parse_fbx import data_types, FBXElem
from .fbx_utils import (
    units_convertor_iter,
    array_to_matrix4,
    similar_values,
    similar_values_iter,
)

# global singleton, assign on execution
fbx_elem_nil = None

# Units convertors...
convert_deg_to_rad_iter = units_convertor_iter("degree", "radian")


def elem_find_first(elem, id_search, default=None):
    for fbx_item in elem.elems:
        if fbx_item.id == id_search:
            return fbx_item
    return default


def elem_find_iter(elem, id_search):
    for fbx_item in elem.elems:
        if fbx_item.id == id_search:
            yield fbx_item


def elem_find_first_string(elem, id_search):
    fbx_item = elem_find_first(elem, id_search)
    if fbx_item is not None:
        assert(len(fbx_item.props) == 1)
        assert(fbx_item.props_type[0] == data_types.STRING)
        return fbx_item.props[0].decode('utf-8')
    return None


def elem_find_first_bytes(elem, id_search, decode=True):
    fbx_item = elem_find_first(elem, id_search)
    if fbx_item is not None:
        assert(len(fbx_item.props) == 1)
        assert(fbx_item.props_type[0] == data_types.STRING)
        return fbx_item.props[0]
    return None


def elem_repr(elem):
    return "%s: props[%d=%r], elems=(%r)" % (
        elem.id,
        len(elem.props),
        ", ".join([repr(p) for p in elem.props]),
        # elem.props_type,
        b", ".join([e.id for e in elem.elems]),
        )


def elem_split_name_class(elem):
    assert(elem.props_type[-2] == data_types.STRING)
    elem_name, elem_class = elem.props[-2].split(b'\x00\x01')
    return elem_name, elem_class


def elem_name_ensure_class(elem, clss=...):
    elem_name, elem_class = elem_split_name_class(elem)
    if clss is not ...:
        assert(elem_class == clss)
    return elem_name.decode('utf-8')


def elem_split_name_class_nodeattr(elem):
    assert(elem.props_type[-2] == data_types.STRING)
    elem_name, elem_class = elem.props[-2].split(b'\x00\x01')
    assert(elem_class == b'NodeAttribute')
    assert(elem.props_type[-1] == data_types.STRING)
    elem_class = elem.props[-1]
    return elem_name, elem_class


def elem_uuid(elem):
    assert(elem.props_type[0] == data_types.INT64)
    return elem.props[0]


def elem_prop_first(elem, default=None):
    return elem.props[0] if (elem is not None) and elem.props else default


# ----
# Support for
# Properties70: { ... P:
def elem_props_find_first(elem, elem_prop_id):

    # support for templates (tuple of elems)
    if type(elem) is not FBXElem:
        assert(type(elem) is tuple)
        for e in elem:
            result = elem_props_find_first(e, elem_prop_id)
            if result is not None:
                return result
        assert(len(elem) > 0)
        return None

    for subelem in elem.elems:
        assert(subelem.id == b'P')
        if subelem.props[0] == elem_prop_id:
            return subelem
    return None


def elem_props_get_color_rgb(elem, elem_prop_id, default=None):
    elem_prop = elem_props_find_first(elem, elem_prop_id)
    if elem_prop is not None:
        assert(elem_prop.props[0] == elem_prop_id)
        if elem_prop.props[1] == b'Color':
            # FBX version 7300
            assert(elem_prop.props[1] == b'Color')
            assert(elem_prop.props[2] == b'')
            assert(elem_prop.props[3] in {b'A', b'A+', b'AU'})
        else:
            assert(elem_prop.props[1] == b'ColorRGB')
            assert(elem_prop.props[2] == b'Color')
        assert(elem_prop.props_type[4:7] == bytes((data_types.FLOAT64,)) * 3)
        return elem_prop.props[4:7]
    return default


def elem_props_get_vector_3d(elem, elem_prop_id, default=None):
    elem_prop = elem_props_find_first(elem, elem_prop_id)
    if elem_prop is not None:
        assert(elem_prop.props_type[4:7] == bytes((data_types.FLOAT64,)) * 3)
        return elem_prop.props[4:7]
    return default


def elem_props_get_number(elem, elem_prop_id, default=None):
    elem_prop = elem_props_find_first(elem, elem_prop_id)
    if elem_prop is not None:
        assert(elem_prop.props[0] == elem_prop_id)
        if elem_prop.props[1] == b'double':
            assert(elem_prop.props[1] == b'double')
            assert(elem_prop.props[2] == b'Number')
        else:
            assert(elem_prop.props[1] == b'Number')
            assert(elem_prop.props[2] == b'')
            assert(elem_prop.props[3] in {b'A', b'A+', b'AU'})

        # we could allow other number types
        assert(elem_prop.props_type[4] == data_types.FLOAT64)

        return elem_prop.props[4]
    return default


def elem_props_get_integer(elem, elem_prop_id, default=None):
    elem_prop = elem_props_find_first(elem, elem_prop_id)
    if elem_prop is not None:
        assert(elem_prop.props[0] == elem_prop_id)
        if elem_prop.props[1] == b'int':
            assert(elem_prop.props[1] == b'int')
            assert(elem_prop.props[2] == b'Integer')
        elif elem_prop.props[1] == b'ULongLong':
            assert(elem_prop.props[1] == b'ULongLong')
            assert(elem_prop.props[2] == b'')

        # we could allow other number types
        assert(elem_prop.props_type[4] in {data_types.INT32, data_types.INT64})

        return elem_prop.props[4]
    return default


def elem_props_get_bool(elem, elem_prop_id, default=None):
    elem_prop = elem_props_find_first(elem, elem_prop_id)
    if elem_prop is not None:
        assert(elem_prop.props[0] == elem_prop_id)
        assert(elem_prop.props[1] == b'bool')
        assert(elem_prop.props[2] == b'')
        assert(elem_prop.props[3] == b'')

        # we could allow other number types
        assert(elem_prop.props_type[4] == data_types.INT32)
        assert(elem_prop.props[4] in {0, 1})

        return bool(elem_prop.props[4])
    return default


def elem_props_get_enum(elem, elem_prop_id, default=None):
    elem_prop = elem_props_find_first(elem, elem_prop_id)
    if elem_prop is not None:
        assert(elem_prop.props[0] == elem_prop_id)
        assert(elem_prop.props[1] == b'enum')
        assert(elem_prop.props[2] == b'')
        assert(elem_prop.props[3] == b'')

        # we could allow other number types
        assert(elem_prop.props_type[4] == data_types.INT32)

        return elem_prop.props[4]
    return default


def elem_props_get_visibility(elem, elem_prop_id, default=None):
    elem_prop = elem_props_find_first(elem, elem_prop_id)
    if elem_prop is not None:
        assert(elem_prop.props[0] == elem_prop_id)
        assert(elem_prop.props[1] == b'Visibility')
        assert(elem_prop.props[2] == b'')
        assert(elem_prop.props[3] in {b'A', b'A+', b'AU'})

        # we could allow other number types
        assert(elem_prop.props_type[4] == data_types.FLOAT64)

        return elem_prop.props[4]
    return default


# ----------------------------------------------------------------------------
# Blender

# ------
# Object

def blen_read_object(fbx_tmpl, fbx_obj, object_data):
    elem_name, elem_class = elem_split_name_class(fbx_obj)
    elem_name_utf8 = elem_name.decode('utf-8')

    const_vector_zero_3d = 0.0, 0.0, 0.0
    const_vector_one_3d = 1.0, 1.0, 1.0

    # Object data must be created already
    obj = bpy.data.objects.new(name=elem_name_utf8, object_data=object_data)

    fbx_props = (elem_find_first(fbx_obj, b'Properties70'),
                 elem_find_first(fbx_tmpl, b'Properties70', fbx_elem_nil))
    assert(fbx_props[0] is not None)

    # ----
    # Misc Attributes

    obj.color[0:3] = elem_props_get_color_rgb(fbx_props, b'Color', (0.8, 0.8, 0.8))
    obj.hide = not bool(elem_props_get_visibility(fbx_props, b'Visibility', 1.0))

    # ----
    # Transformation

    # This is quite involved, 'fbxRNode.cpp' from openscenegraph used as a reference

    loc = elem_props_get_vector_3d(fbx_props, b'Lcl Translation', const_vector_zero_3d)
    rot = elem_props_get_vector_3d(fbx_props, b'Lcl Rotation', const_vector_zero_3d)
    sca = elem_props_get_vector_3d(fbx_props, b'Lcl Scaling', const_vector_one_3d)

    rot_ofs = elem_props_get_vector_3d(fbx_props, b'RotationOffset', const_vector_zero_3d)
    rot_piv = elem_props_get_vector_3d(fbx_props, b'RotationPivot', const_vector_zero_3d)
    sca_ofs = elem_props_get_vector_3d(fbx_props, b'ScalingOffset', const_vector_zero_3d)
    sca_piv = elem_props_get_vector_3d(fbx_props, b'ScalingPivot', const_vector_zero_3d)

    is_rot_act = elem_props_get_bool(fbx_props, b'RotationActive', False)

    if is_rot_act:
        pre_rot = elem_props_get_vector_3d(fbx_props, b'PreRotation', const_vector_zero_3d)
        pst_rot = elem_props_get_vector_3d(fbx_props, b'PostRotation', const_vector_zero_3d)
        rot_ord = {
            0: 'XYZ',
            1: 'XYZ',
            2: 'XZY',
            3: 'YZX',
            4: 'YXZ',
            5: 'ZXY',
            6: 'ZYX',
            }.get(elem_props_get_enum(fbx_props, b'RotationOrder', 0))
    else:
        pre_rot = const_vector_zero_3d
        pst_rot = const_vector_zero_3d
        rot_ord = 'XYZ'

    from mathutils import Matrix, Euler
    from math import pi

    # translation
    lcl_translation = Matrix.Translation(loc)

    # rotation
    if obj.type == 'CAMERA':
        rot_alt_mat = Matrix.Rotation(pi / -2.0, 4, 'Y')
    elif obj.type == 'LAMP':
        rot_alt_mat = Matrix.Rotation(pi / -2.0, 4, 'X')
    else:
        rot_alt_mat = Matrix()

    # rotation
    lcl_rot = Euler(convert_deg_to_rad_iter(rot), rot_ord).to_matrix().to_4x4() * rot_alt_mat
    pre_rot = Euler(convert_deg_to_rad_iter(pre_rot), rot_ord).to_matrix().to_4x4()
    pst_rot = Euler(convert_deg_to_rad_iter(pst_rot), rot_ord).to_matrix().to_4x4()

    rot_ofs = Matrix.Translation(rot_ofs)
    rot_piv = Matrix.Translation(rot_piv)
    sca_ofs = Matrix.Translation(sca_ofs)
    sca_piv = Matrix.Translation(sca_piv)

    # scale
    lcl_scale = Matrix()
    lcl_scale[0][0], lcl_scale[1][1], lcl_scale[2][2] = sca

    obj.matrix_basis = (
        lcl_translation *
        rot_ofs *
        rot_piv *
        pre_rot *
        lcl_rot *
        pst_rot *
        rot_piv.inverted() *
        sca_ofs *
        sca_piv *
        lcl_scale *
        sca_piv.inverted()
        )

    return obj


# ----
# Mesh

def blen_read_geom_layerinfo(fbx_layer):
    return (
        elem_find_first_string(fbx_layer, b'Name'),
        elem_find_first_bytes(fbx_layer, b'MappingInformationType'),
        elem_find_first_bytes(fbx_layer, b'ReferenceInformationType'),
        )


def blen_read_geom_array_mapped_vert(
        mesh, blen_data, blend_attr,
        fbx_layer_data, fbx_layer_index,
        fbx_layer_mapping, fbx_layer_ref,
        stride, item_size, descr,
        ):
    # TODO, generic mapping apply function
    if fbx_layer_mapping == b'ByVertice':
        if fbx_layer_ref == b'Direct':
            assert(fbx_layer_index is None)
            # TODO, more generic support for mapping types
            for i, blen_data_item in enumerate(blen_data):
                setattr(blen_data_item, blend_attr,
                        fbx_layer_data[(i * stride): (i * stride) + item_size])
            return True
        else:
            print("warning layer %r ref type unsupported: %r" % (descr, fbx_layer_ref))
    else:
        print("warning layer %r mapping type unsupported: %r" % (descr, fbx_layer_mapping))

    return False


def blen_read_geom_array_mapped_edge(
        mesh, blen_data, blend_attr,
        fbx_layer_data, fbx_layer_index,
        fbx_layer_mapping, fbx_layer_ref,
        stride, item_size, descr,
        xform=None,
        ):
    if fbx_layer_mapping == b'ByEdge':
        if fbx_layer_ref == b'Direct':
            if stride == 1:
                if xform is None:
                    for i, blen_data_item in enumerate(blen_data):
                        setattr(blen_data_item, blend_attr,
                                fbx_layer_data[i])
                else:
                    for i, blen_data_item in enumerate(blen_data):
                        setattr(blen_data_item, blend_attr,
                                xform(fbx_layer_data[i]))
            else:
                if xform is None:
                    for i, blen_data_item in enumerate(blen_data):
                        setattr(blen_data_item, blend_attr,
                                fbx_layer_data[(i * stride): (i * stride) + item_size])
                else:
                    for i, blen_data_item in enumerate(blen_data):
                        setattr(blen_data_item, blend_attr,
                                xform(fbx_layer_data[(i * stride): (i * stride) + item_size]))
            return True
        else:
            print("warning layer %r ref type unsupported: %r" % (descr, fbx_layer_ref))
    else:
        print("warning layer %r mapping type unsupported: %r" % (descr, fbx_layer_mapping))

    return False


def blen_read_geom_array_mapped_polygon(
        mesh, blen_data, blend_attr,
        fbx_layer_data, fbx_layer_index,
        fbx_layer_mapping, fbx_layer_ref,
        stride, item_size, descr,
        xform=None,
        ):
    if fbx_layer_mapping == b'ByPolygon':
        if fbx_layer_ref == b'IndexToDirect':
            if stride == 1:
                for i, blen_data_item in enumerate(blen_data):
                    setattr(blen_data_item, blend_attr,
                            fbx_layer_data[i])
            else:
                for i, blen_data_item in enumerate(blen_data):
                    setattr(blen_data_item, blend_attr,
                            fbx_layer_data[(i * stride): (i * stride) + item_size])
            return True
        elif fbx_layer_ref == b'Direct':
            # looks like direct may have different meanings!
            assert(stride == 1)
            if xform is None:
                for i in range(len(fbx_layer_data)):
                    setattr(blen_data[i], blend_attr, fbx_layer_data[i])
            else:
                for i in range(len(fbx_layer_data)):
                    setattr(blen_data[i], blend_attr, xform(fbx_layer_data[i]))
            return True
        else:
            print("warning layer %r ref type unsupported: %r" % (descr, fbx_layer_ref))
    else:
        print("warning layer %r mapping type unsupported: %r" % (descr, fbx_layer_mapping))

    return False


def blen_read_geom_array_mapped_polyloop(
        mesh, blen_data, blend_attr,
        fbx_layer_data, fbx_layer_index,
        fbx_layer_mapping, fbx_layer_ref,
        stride, item_size, descr,
        ):
    if fbx_layer_mapping == b'ByPolygonVertex':
        if fbx_layer_ref == b'IndexToDirect':
            assert(fbx_layer_index is not None)
            for i, j in enumerate(fbx_layer_index):
                if j != -1:
                    setattr(blen_data[i], blend_attr,
                            fbx_layer_data[(j * stride): (j * stride) + item_size])
            return True
        else:
            print("warning layer %r ref type unsupported: %r" % (descr, fbx_layer_ref))
    elif fbx_layer_mapping == b'ByVertice':
        if fbx_layer_ref == b'Direct':
            assert(fbx_layer_index is None)
            loops = mesh.loops
            polygons = mesh.polygons
            for p in polygons:
                for i in p.loop_indices:
                    j = loops[i].vertex_index
                    setattr(blen_data[i], blend_attr,
                            fbx_layer_data[(j * stride): (j * stride) + item_size])
        else:
            print("warning layer %r ref type unsupported: %r" % (descr, fbx_layer_ref))
    else:
        print("warning layer %r mapping type unsupported: %r" % (descr, fbx_layer_mapping))

    return False


def blen_read_geom_layer_material(fbx_obj, mesh):
    fbx_layer = elem_find_first(fbx_obj, b'LayerElementMaterial')

    if fbx_layer is None:
        return

    (fbx_layer_name,
     fbx_layer_mapping,
     fbx_layer_ref,
     ) = blen_read_geom_layerinfo(fbx_layer)

    if fbx_layer_mapping == b'AllSame':
        # only to quiet warning
        return

    layer_id = b'Materials'
    fbx_layer_data = elem_prop_first(elem_find_first(fbx_layer, layer_id))

    blen_data = mesh.polygons
    blen_read_geom_array_mapped_polygon(
        mesh, blen_data, "material_index",
        fbx_layer_data, None,
        fbx_layer_mapping, fbx_layer_ref,
        1, 1, layer_id,
        )


def blen_read_geom_layer_uv(fbx_obj, mesh):
    for layer_id in (b'LayerElementUV',):
        for fbx_layer in elem_find_iter(fbx_obj, layer_id):
            # all should be valid
            (fbx_layer_name,
             fbx_layer_mapping,
             fbx_layer_ref,
             ) = blen_read_geom_layerinfo(fbx_layer)

            fbx_layer_data = elem_prop_first(elem_find_first(fbx_layer, b'UV'))
            fbx_layer_index = elem_prop_first(elem_find_first(fbx_layer, b'UVIndex'))

            uv_tex = mesh.uv_textures.new(name=fbx_layer_name)
            uv_lay = mesh.uv_layers[-1]
            blen_data = uv_lay.data[:]

            # some valid files omit this data
            if fbx_layer_data is None:
                print("%r %r missing data" % (layer_id, fbx_layer_name))
                continue

            blen_read_geom_array_mapped_polyloop(
                mesh, blen_data, "uv",
                fbx_layer_data, fbx_layer_index,
                fbx_layer_mapping, fbx_layer_ref,
                2, 2, layer_id,
                )


def blen_read_geom_layer_color(fbx_obj, mesh):
    # almost same as UV's
    for layer_id in (b'LayerElementColor',):
        for fbx_layer in elem_find_iter(fbx_obj, layer_id):
            # all should be valid
            (fbx_layer_name,
             fbx_layer_mapping,
             fbx_layer_ref,
             ) = blen_read_geom_layerinfo(fbx_layer)

            fbx_layer_data = elem_prop_first(elem_find_first(fbx_layer, b'Colors'))
            fbx_layer_index = elem_prop_first(elem_find_first(fbx_layer, b'ColorIndex'))

            color_lay = mesh.vertex_colors.new(name=fbx_layer_name)
            blen_data = color_lay.data[:]

            # some valid files omit this data
            if fbx_layer_data is None:
                print("%r %r missing data" % (layer_id, fbx_layer_name))
                continue

            # ignore alpha layer (read 4 items into 3)
            blen_read_geom_array_mapped_polyloop(
                mesh, blen_data, "color",
                fbx_layer_data, fbx_layer_index,
                fbx_layer_mapping, fbx_layer_ref,
                4, 3, layer_id,
                )


def blen_read_geom_layer_smooth(fbx_obj, mesh):
    fbx_layer = elem_find_first(fbx_obj, b'LayerElementSmoothing')

    if fbx_layer is None:
        return False

    # all should be valid
    (fbx_layer_name,
     fbx_layer_mapping,
     fbx_layer_ref,
     ) = blen_read_geom_layerinfo(fbx_layer)

    layer_id = b'Smoothing'
    fbx_layer_data = elem_prop_first(elem_find_first(fbx_layer, layer_id))

    # udk has 'Direct' mapped, with no Smoothing, not sure why, but ignore these
    if fbx_layer_data is None:
        return False

    if fbx_layer_mapping == b'ByEdge':
        # some models have bad edge data, we cant use this info...
        if not mesh.edges:
            return False

        blen_data = mesh.edges
        ok_smooth = blen_read_geom_array_mapped_edge(
            mesh, blen_data, "use_edge_sharp",
            fbx_layer_data, None,
            fbx_layer_mapping, fbx_layer_ref,
            1, 1, layer_id,
            xform=lambda s: not s,
            )
        return ok_smooth
    elif fbx_layer_mapping == b'ByPolygon':
        blen_data = mesh.polygons
        return blen_read_geom_array_mapped_polygon(
            mesh, blen_data, "use_smooth",
            fbx_layer_data, None,
            fbx_layer_mapping, fbx_layer_ref,
            1, 1, layer_id,
            xform=lambda s: (s != 0),  # smoothgroup bitflags, treat as booleans for now
            )
    else:
        print("warning layer %r mapping type unsupported: %r" % (fbx_layer.id, fbx_layer_mapping))
        return False


def blen_read_geom_layer_normal(fbx_obj, mesh):
    fbx_layer = elem_find_first(fbx_obj, b'LayerElementNormal')

    if fbx_layer is None:
        return False

    (fbx_layer_name,
     fbx_layer_mapping,
     fbx_layer_ref,
     ) = blen_read_geom_layerinfo(fbx_layer)

    layer_id = b'Normals'
    fbx_layer_data = elem_prop_first(elem_find_first(fbx_layer, layer_id))

    blen_data = mesh.vertices

    return blen_read_geom_array_mapped_vert(
        mesh, blen_data, "normal",
        fbx_layer_data, None,
        fbx_layer_mapping, fbx_layer_ref,
        3, 3, layer_id,
        )


def blen_read_geom(fbx_tmpl, fbx_obj):
    # TODO, use 'fbx_tmpl'
    elem_name_utf8 = elem_name_ensure_class(fbx_obj, b'Geometry')

    fbx_verts = elem_prop_first(elem_find_first(fbx_obj, b'Vertices'))
    fbx_polys = elem_prop_first(elem_find_first(fbx_obj, b'PolygonVertexIndex'))
    fbx_edges = elem_prop_first(elem_find_first(fbx_obj, b'Edges'))

    if fbx_verts is None:
        fbx_verts = ()
    if fbx_polys is None:
        fbx_polys = ()

    mesh = bpy.data.meshes.new(name=elem_name_utf8)
    mesh.vertices.add(len(fbx_verts) // 3)
    mesh.vertices.foreach_set("co", fbx_verts)

    if fbx_polys:
        mesh.loops.add(len(fbx_polys))
        poly_loop_starts = []
        poly_loop_totals = []
        poly_loop_prev = 0
        for i, l in enumerate(mesh.loops):
            index = fbx_polys[i]
            if index < 0:
                poly_loop_starts.append(poly_loop_prev)
                poly_loop_totals.append((i - poly_loop_prev) + 1)
                poly_loop_prev = i + 1
                index ^= -1
            l.vertex_index = index

        mesh.polygons.add(len(poly_loop_starts))
        mesh.polygons.foreach_set("loop_start", poly_loop_starts)
        mesh.polygons.foreach_set("loop_total", poly_loop_totals)

        blen_read_geom_layer_material(fbx_obj, mesh)
        blen_read_geom_layer_uv(fbx_obj, mesh)
        blen_read_geom_layer_color(fbx_obj, mesh)

    if fbx_edges:
        # edges in fact index the polygons (NOT the vertices)
        import array
        tot_edges = len(fbx_edges)
        edges_conv = array.array('i', [0]) * (tot_edges * 2)

        edge_index = 0
        for i in fbx_edges:
            e_a = fbx_polys[i]
            if e_a >= 0:
                e_b = fbx_polys[i + 1]
                if e_b < 0:
                    e_b ^= -1
            else:
                # Last index of polygon, wrap back to the start.

                # ideally we wouldn't have to search back,
                # but it should only be 2-3 iterations.
                j = i - 1
                while j >= 0 and fbx_polys[j] >= 0:
                    j -= 1
                e_a ^= -1
                e_b = fbx_polys[j + 1]

            edges_conv[edge_index] = e_a
            edges_conv[edge_index + 1] = e_b
            edge_index += 2

        mesh.edges.add(tot_edges)
        mesh.edges.foreach_set("vertices", edges_conv)

    # must be after edge, face loading.
    ok_smooth = blen_read_geom_layer_smooth(fbx_obj, mesh)

    ok_normals = blen_read_geom_layer_normal(fbx_obj, mesh)

    mesh.validate()

    if not ok_normals:
        mesh.calc_normals()

    if not ok_smooth:
        for p in mesh.polygons:
            p.use_smooth = True

    return mesh


def blen_read_shape(fbx_tmpl, fbx_sdata, fbx_bcdata, meshes, scene, global_matrix):
    from mathutils import Vector

    elem_name_utf8 = elem_name_ensure_class(fbx_sdata, b'Geometry')
    indices = elem_prop_first(elem_find_first(fbx_sdata, b'Indexes'), default=())
    dvcos = tuple(co for co in zip(*[iter(elem_prop_first(elem_find_first(fbx_sdata, b'Vertices'), default=()))] * 3))
    # We completely ignore normals here!
    weight = elem_prop_first(elem_find_first(fbx_bcdata, b'DeformPercent'), default=100.0) / 100.0
    vgweights = tuple(vgw / 100.0 for vgw in elem_prop_first(elem_find_first(fbx_bcdata, b'FullWeights'), default=()))

    assert(len(vgweights) == len(indices) == len(dvcos))
    create_vg = bool(set(vgweights) - {1.0})

    for me, objects in meshes:
        vcos = tuple((idx, me.vertices[idx].co + Vector(dvco)) for idx, dvco in zip(indices, dvcos))
        objects = list({blen_o for fbx_o, blen_o in objects})
        assert(objects)

        if me.shape_keys is None:
            objects[0].shape_key_add(name="Basis", from_mix=False)
        objects[0].shape_key_add(name=elem_name_utf8, from_mix=False)
        me.shape_keys.use_relative = True  # Should already be set as such.

        kb = me.shape_keys.key_blocks[elem_name_utf8]
        for idx, co in vcos:
            kb.data[idx].co[:] = co
        kb.value = weight

        # Add vgroup if necessary.
        if create_vg:
            add_vgroup_to_objects(indices, vgweights, elem_name_utf8, objects)
            kb.vertex_group = elem_name_utf8


# --------
# Material

def blen_read_material(fbx_tmpl, fbx_obj, cycles_material_wrap_map, use_cycles):
    elem_name_utf8 = elem_name_ensure_class(fbx_obj, b'Material')

    ma = bpy.data.materials.new(name=elem_name_utf8)

    const_color_white = 1.0, 1.0, 1.0

    fbx_props = (elem_find_first(fbx_obj, b'Properties70'),
                 elem_find_first(fbx_tmpl, b'Properties70', fbx_elem_nil))
    assert(fbx_props[0] is not None)

    ma_diff = elem_props_get_color_rgb(fbx_props, b'DiffuseColor', const_color_white)
    ma_spec = elem_props_get_color_rgb(fbx_props, b'SpecularColor', const_color_white)
    ma_alpha = elem_props_get_number(fbx_props, b'Opacity', 1.0)
    ma_spec_intensity = ma.specular_intensity = elem_props_get_number(fbx_props, b'SpecularFactor', 0.25) * 2.0
    ma_spec_hardness = elem_props_get_number(fbx_props, b'Shininess', 9.6)
    ma_refl_factor = elem_props_get_number(fbx_props, b'ReflectionFactor', 0.0)
    ma_refl_color = elem_props_get_color_rgb(fbx_props, b'ReflectionColor', const_color_white)

    if use_cycles:
        from . import cycles_shader_compat
        # viewport color
        ma.diffuse_color = ma_diff

        ma_wrap = cycles_shader_compat.CyclesShaderWrapper(ma)
        ma_wrap.diffuse_color_set(ma_diff)
        ma_wrap.specular_color_set([c * ma_spec_intensity for c in ma_spec])
        ma_wrap.hardness_value_set(((ma_spec_hardness + 3.0) / 5.0) - 0.65)
        ma_wrap.alpha_value_set(ma_alpha)
        ma_wrap.reflect_factor_set(ma_refl_factor)
        ma_wrap.reflect_color_set(ma_refl_color)

        cycles_material_wrap_map[ma] = ma_wrap
    else:
        # TODO, number BumpFactor isnt used yet
        ma.diffuse_color = ma_diff
        ma.specular_color = ma_spec
        ma.alpha = ma_alpha
        ma.specular_intensity = ma_spec_intensity
        ma.specular_hardness = ma_spec_hardness * 5.10 + 1.0

        if ma_refl_factor != 0.0:
            ma.raytrace_mirror.use = True
            ma.raytrace_mirror.reflect_factor = ma_refl_factor
            ma.mirror_color = ma_refl_color

    return ma


# -------
# Texture

def blen_read_texture(fbx_tmpl, fbx_obj, basedir, image_cache,
                      use_image_search):
    import os
    from bpy_extras import image_utils

    elem_name_utf8 = elem_name_ensure_class(fbx_obj, b'Texture')

    filepath = elem_find_first_string(fbx_obj, b'FileName')
    if os.sep == '/':
        filepath = filepath.replace('\\', '/')
    else:
        filepath = filepath.replace('/', '\\')

    image = image_cache.get(filepath)
    if image is not None:
        return image

    image = image_utils.load_image(
        filepath,
        dirname=basedir,
        place_holder=True,
        recursive=use_image_search,
        )

    image_cache[filepath] = image
    # name can be ../a/b/c
    image.name = os.path.basename(elem_name_utf8)

    return image


def blen_read_camera(fbx_tmpl, fbx_obj, global_scale):
    # meters to inches
    M2I = 0.0393700787

    elem_name_utf8 = elem_name_ensure_class(fbx_obj, b'NodeAttribute')

    fbx_props = (elem_find_first(fbx_obj, b'Properties70'),
                 elem_find_first(fbx_tmpl, b'Properties70', fbx_elem_nil))
    assert(fbx_props[0] is not None)

    camera = bpy.data.cameras.new(name=elem_name_utf8)

    camera.lens = elem_props_get_number(fbx_props, b'FocalLength', 35.0)
    camera.sensor_width = elem_props_get_number(fbx_props, b'FilmWidth', 32.0 * M2I) / M2I
    camera.sensor_height = elem_props_get_number(fbx_props, b'FilmHeight', 32.0 * M2I) / M2I

    filmaspect = camera.sensor_width / camera.sensor_height
    # film offset
    camera.shift_x = elem_props_get_number(fbx_props, b'FilmOffsetX', 0.0) / (M2I * camera.sensor_width)
    camera.shift_y = elem_props_get_number(fbx_props, b'FilmOffsetY', 0.0) / (M2I * camera.sensor_height * filmaspect)

    camera.clip_start = elem_props_get_number(fbx_props, b'NearPlane', 0.01) * global_scale
    camera.clip_end = elem_props_get_number(fbx_props, b'FarPlane', 100.0) * global_scale

    return camera


def blen_read_light(fbx_tmpl, fbx_obj, global_scale):
    import math
    elem_name_utf8 = elem_name_ensure_class(fbx_obj, b'NodeAttribute')

    fbx_props = (elem_find_first(fbx_obj, b'Properties70'),
                 elem_find_first(fbx_tmpl, b'Properties70', fbx_elem_nil))
    # rare
    if fbx_props[0] is None:
        lamp = bpy.data.lamps.new(name=elem_name_utf8, type='POINT')
        return lamp

    light_type = {
        0: 'POINT',
        1: 'SUN',
        2: 'SPOT'}.get(elem_props_get_enum(fbx_props, b'LightType', 0), 'POINT')

    lamp = bpy.data.lamps.new(name=elem_name_utf8, type=light_type)

    if light_type == 'SPOT':
        spot_size = elem_props_get_number(fbx_props, b'OuterAngle', None)
        if spot_size is None:
            # Deprecated.
            spot_size = elem_props_get_number(fbx_props, b'Cone angle', 45.0)
        lamp.spot_size = math.radians(spot_size)

        spot_blend = elem_props_get_number(fbx_props, b'InnerAngle', None)
        if spot_blend is None:
            # Deprecated.
            spot_blend = elem_props_get_number(fbx_props, b'HotSpot', 45.0)
        lamp.spot_blend = 1.0 - (spot_blend / spot_size)

    # TODO, cycles
    lamp.color = elem_props_get_color_rgb(fbx_props, b'Color', (1.0, 1.0, 1.0))
    lamp.energy = elem_props_get_number(fbx_props, b'Intensity', 100.0) / 100.0
    lamp.distance = elem_props_get_number(fbx_props, b'DecayStart', 25.0) * global_scale
    lamp.shadow_method = ('RAY_SHADOW' if elem_props_get_bool(fbx_props, b'CastShadow', True) else 'NOSHADOW')
    lamp.shadow_color = elem_props_get_color_rgb(fbx_props, b'ShadowColor', (0.0, 0.0, 0.0))

    return lamp


def is_ascii(filepath, size):
    with open(filepath, 'r', encoding="utf-8") as f:
        try:
            f.read(size)
            return True
        except UnicodeDecodeError:
            pass

    return False


def load(operator, context, filepath="",
         use_manual_orientation=False,
         axis_forward='-Z',
         axis_up='Y',
         global_scale=1.0,
         use_cycles=True,
         use_image_search=False,
         use_alpha_decals=False,
         decal_offset=0.0):

    global fbx_elem_nil
    fbx_elem_nil = FBXElem('', (), (), ())

    import os, time
    from bpy_extras.io_utils import axis_conversion
    from mathutils import Matrix

    from . import parse_fbx
    from .fbx_utils import RIGHT_HAND_AXES, FBX_FRAMERATES

    start_time = time.process_time()

    # detect ascii files
    if is_ascii(filepath, 24):
        operator.report({'ERROR'}, "ASCII FBX files are not supported %r" % filepath)
        return {'CANCELLED'}

    try:
        elem_root, version = parse_fbx.parse(filepath)
    except:
        import traceback
        traceback.print_exc()

        operator.report({'ERROR'}, "Couldn't open file %r" % filepath)
        return {'CANCELLED'}

    if version < 7100:
        operator.report({'ERROR'}, "Version %r unsupported, must be %r or later" % (version, 7100))
        return {'CANCELLED'}

    if bpy.ops.object.mode_set.poll():
        bpy.ops.object.mode_set(mode='OBJECT', toggle=False)

    # deselect all
    if bpy.ops.object.select_all.poll():
        bpy.ops.object.select_all(action='DESELECT')

    basedir = os.path.dirname(filepath)

    cycles_material_wrap_map = {}
    image_cache = {}
    if not use_cycles:
        texture_cache = {}

    # Tables: (FBX_byte_id -> [FBX_data, None or Blender_datablock])
    fbx_table_nodes = {}

    if use_alpha_decals: