import_fbx.py

    #     (b'Geometry', b'KFbxMesh')
    fbx_templates = {}

    def _():
        if fbx_defs is not None:
            for fbx_def in fbx_defs.elems:
                if fbx_def.id == b'ObjectType':
                    for fbx_subdef in fbx_def.elems:
                        if fbx_subdef.id == b'PropertyTemplate':
                            assert(fbx_def.props_type == b'S')
                            assert(fbx_subdef.props_type == b'S')
                            # (b'Texture', b'KFbxFileTexture') - eg.
                            key = fbx_def.props[0], fbx_subdef.props[0]
                            fbx_templates[key] = fbx_subdef
    _(); del _

    def fbx_template_get(key):
        ret = fbx_templates.get(key, fbx_elem_nil)
        if ret is None:
            # Newest FBX (7.4 and above) use no more 'K' in their type names...
            key = (key[0], key[1][1:])
            return fbx_templates.get(key, fbx_elem_nil)
        return ret

    # ----
    # Build FBX node-table
    def _():
        for fbx_obj in fbx_nodes.elems:
            # TODO, investigate what other items after first 3 may be
            assert(fbx_obj.props_type[:3] == b'LSS')
            fbx_uuid = elem_uuid(fbx_obj)
            fbx_table_nodes[fbx_uuid] = [fbx_obj, None]
    _(); del _

    # ----
    # Load in the data
    # http://download.autodesk.com/us/fbx/20112/FBX_SDK_HELP/index.html?url=
    #        WS73099cc142f487551fea285e1221e4f9ff8-7fda.htm,topicNumber=d0e6388

    fbx_connection_map = {}
    fbx_connection_map_reverse = {}

    def _():
        for fbx_link in fbx_connections.elems:
            c_type = fbx_link.props[0]
            if fbx_link.props_type[1:3] == b'LL':
                c_src, c_dst = fbx_link.props[1:3]
                fbx_connection_map.setdefault(c_src, []).append((c_dst, fbx_link))
                fbx_connection_map_reverse.setdefault(c_dst, []).append((c_src, fbx_link))
    _(); del _

    # ----
    # Load mesh data
    def _():
        fbx_tmpl = fbx_template_get((b'Geometry', b'KFbxMesh'))

        for fbx_uuid, fbx_item in fbx_table_nodes.items():
            fbx_obj, blen_data = fbx_item
            if fbx_obj.id != b'Geometry':
                continue
            if fbx_obj.props[-1] == b'Mesh':
                assert(blen_data is None)
                fbx_item[1] = blen_read_geom(fbx_tmpl, fbx_obj, settings)
    _(); del _

    # ----
    # Load material data
    def _():
        fbx_tmpl = fbx_template_get((b'Material', b'KFbxSurfacePhong'))
        # b'KFbxSurfaceLambert'

        for fbx_uuid, fbx_item in fbx_table_nodes.items():
            fbx_obj, blen_data = fbx_item
            if fbx_obj.id != b'Material':
                continue
            assert(blen_data is None)
            fbx_item[1] = blen_read_material(fbx_tmpl, fbx_obj, settings)
    _(); del _

    # ----
    # Load image data
    def _():
        fbx_tmpl = fbx_template_get((b'Texture', b'KFbxFileTexture'))

        for fbx_uuid, fbx_item in fbx_table_nodes.items():
            fbx_obj, blen_data = fbx_item
            if fbx_obj.id != b'Texture':
                continue
            fbx_item[1] = blen_read_texture(fbx_tmpl, fbx_obj, basedir, settings)
    _(); del _

    # ----
    # Load camera data
    def _():
        fbx_tmpl = fbx_template_get((b'NodeAttribute', b'KFbxCamera'))

        for fbx_uuid, fbx_item in fbx_table_nodes.items():
            fbx_obj, blen_data = fbx_item
            if fbx_obj.id != b'NodeAttribute':
                continue
            if fbx_obj.props[-1] == b'Camera':
                assert(blen_data is None)
                fbx_item[1] = blen_read_camera(fbx_tmpl, fbx_obj, global_scale)
    _(); del _

    # ----
    # Load lamp data
    def _():
        fbx_tmpl = fbx_template_get((b'NodeAttribute', b'KFbxLight'))

        for fbx_uuid, fbx_item in fbx_table_nodes.items():
            fbx_obj, blen_data = fbx_item
            if fbx_obj.id != b'NodeAttribute':
                continue
            if fbx_obj.props[-1] == b'Light':
                assert(blen_data is None)
                fbx_item[1] = blen_read_light(fbx_tmpl, fbx_obj, global_scale)
    _(); del _

    # ----
    # Connections
    def connection_filter_ex(fbx_uuid, fbx_id, dct):
        return [(c_found[0], c_found[1], c_type)
                for (c_uuid, c_type) in dct.get(fbx_uuid, ())
                # 0 is used for the root node, which isnt in fbx_table_nodes
                for c_found in (() if c_uuid is 0 else (fbx_table_nodes.get(c_uuid, (None, None)),))
                if (fbx_id is None) or (c_found[0] and c_found[0].id == fbx_id)]

    def connection_filter_forward(fbx_uuid, fbx_id):
        return connection_filter_ex(fbx_uuid, fbx_id, fbx_connection_map)

    def connection_filter_reverse(fbx_uuid, fbx_id):
        return connection_filter_ex(fbx_uuid, fbx_id, fbx_connection_map_reverse)

    # -- temporary helper hierarchy to build armatures and objects from
    # lookup from uuid to helper node. Used to build parent-child relations and later to look up animated nodes.
    fbx_helper_nodes = {}

    def _():
        # We build an intermediate hierarchy used to:
        # - Calculate and store bone orientation correction matrices. The same matrices will be reused for animation.
        # - Find/insert armature nodes.
        # - Filter leaf bones.

        # create scene root
        fbx_helper_nodes[0] = root_helper = FbxImportHelperNode(None, None, None, False)
        root_helper.is_root = True

        # add fbx nodes
        fbx_tmpl = fbx_template_get((b'Model', b'KFbxNode'))
        for a_uuid, a_item in fbx_table_nodes.items():
            fbx_obj, bl_data = a_item
            if fbx_obj is None or fbx_obj.id != b'Model':
                continue

            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)

            transform_data = blen_read_object_transform_preprocess(fbx_props, fbx_obj, Matrix(), use_prepost_rot)
            is_bone = fbx_obj.props[2] in {b'LimbNode'}  # Note: 'Root' "bones" are handled as (armature) objects.
            fbx_helper_nodes[a_uuid] = FbxImportHelperNode(fbx_obj, bl_data, transform_data, is_bone)

        # add parent-child relations and add blender data to the node
        for fbx_link in fbx_connections.elems:
            if fbx_link.props[0] != b'OO':
                continue
            if fbx_link.props_type[1:3] == b'LL':
                c_src, c_dst = fbx_link.props[1:3]
                parent = fbx_helper_nodes.get(c_dst)
                if parent is None:
                    continue

                child = fbx_helper_nodes.get(c_src)
                if child is None:
                    # add blender data (meshes, lights, cameras, etc.) to a helper node
                    fbx_sdata, bl_data = p_item = fbx_table_nodes.get(c_src, (None, None))
                    if fbx_sdata is None:
                        continue
                    if fbx_sdata.id in {b'Material', b'Texture', b'Video'}:
                        continue
                    parent.bl_data = bl_data
                else:
                    # set parent
                    child.parent = parent

        # find armatures (either an empty below a bone or a new node inserted at the bone
        root_helper.find_armatures()

        # mark nodes that have bone children
        root_helper.find_bone_children()

        # mark nodes that need a bone to attach child-bones to
        root_helper.find_fake_bones()

        # mark leaf nodes that are only required to mark the end of their parent bone
        if settings.ignore_leaf_bones:
            root_helper.mark_leaf_bones()

        # What a mess! Some bones have several BindPoses, some have none, clusters contain a bind pose as well,
        # and you can have several clusters per bone!
        # Maybe some conversion can be applied to put them all into the same frame of reference?

        # get the bind pose from pose elements
        for a_uuid, a_item in fbx_table_nodes.items():
            fbx_obj, bl_data = a_item
            if fbx_obj is None:
                continue
            if fbx_obj.id != b'Pose':
                continue
            if fbx_obj.props[2] != b'BindPose':
                continue
            for fbx_pose_node in fbx_obj.elems:
                if fbx_pose_node.id != b'PoseNode':
                    continue
                node_elem = elem_find_first(fbx_pose_node, b'Node')
                node = elem_uuid(node_elem)
                matrix_elem = elem_find_first(fbx_pose_node, b'Matrix')
                matrix = array_to_matrix4(matrix_elem.props[0]) if matrix_elem else None
                bone = fbx_helper_nodes.get(node)
                if bone and matrix:
                    # Store the matrix in the helper node.
                    # There may be several bind pose matrices for the same node, but in tests they seem to be identical.
                    bone.bind_matrix = matrix  # global space

        # get clusters and bind pose
        for helper_uuid, helper_node in fbx_helper_nodes.items():
            if not helper_node.is_bone:
                continue
            for cluster_uuid, cluster_link in fbx_connection_map.get(helper_uuid, ()):
                if cluster_link.props[0] != b'OO':
                    continue
                fbx_cluster, _ = fbx_table_nodes.get(cluster_uuid, (None, None))
                if fbx_cluster is None or fbx_cluster.id != b'Deformer' or fbx_cluster.props[2] != b'Cluster':
                    continue

                # Get the bind pose from the cluster:
                tx_mesh_elem = elem_find_first(fbx_cluster, b'Transform', default=None)
                tx_mesh = array_to_matrix4(tx_mesh_elem.props[0]) if tx_mesh_elem else Matrix()

                tx_bone_elem = elem_find_first(fbx_cluster, b'TransformLink', default=None)
                tx_bone = array_to_matrix4(tx_bone_elem.props[0]) if tx_bone_elem else None

                tx_arm_elem = elem_find_first(fbx_cluster, b'TransformAssociateModel', default=None)
                tx_arm = array_to_matrix4(tx_arm_elem.props[0]) if tx_arm_elem else Matrix()

                mesh_matrix = tx_mesh
                armature_matrix = tx_arm

                if tx_bone:
                    mesh_matrix = tx_bone * mesh_matrix
                    helper_node.bind_matrix = tx_bone  # overwrite the bind matrix

                # Get the meshes driven by this cluster: (Shouldn't that be only one?)
                meshes = set()
                for skin_uuid, skin_link in fbx_connection_map.get(cluster_uuid):
                    if skin_link.props[0] != b'OO':
                        continue
                    fbx_skin, _ = fbx_table_nodes.get(skin_uuid, (None, None))
                    if fbx_skin is None or fbx_skin.id != b'Deformer' or fbx_skin.props[2] != b'Skin':
                        continue
                    for mesh_uuid, mesh_link in fbx_connection_map.get(skin_uuid):
                        if mesh_link.props[0] != b'OO':
                            continue
                        fbx_mesh, _ = fbx_table_nodes.get(mesh_uuid, (None, None))
                        if fbx_mesh is None or fbx_mesh.id != b'Geometry' or fbx_mesh.props[2] != b'Mesh':
                            continue
                        for object_uuid, object_link in fbx_connection_map.get(mesh_uuid):
                            if object_link.props[0] != b'OO':
                                continue
                            mesh_node = fbx_helper_nodes[object_uuid]
                            if mesh_node:
                                # ----
                                # If we get a valid mesh matrix (in bone space), store armature and mesh global matrices, we need to set temporarily
                                # both objects to those matrices when actually binding them via the modifier.
                                # Note we assume all bones were bound with the same mesh/armature (global) matrix, we do not support otherwise
                                # in Blender anyway!
                                mesh_node.armature_setup = (mesh_matrix, armature_matrix)
                                meshes.add(mesh_node)

                helper_node.clusters.append((fbx_cluster, meshes))

        # convert bind poses from global space into local space
        root_helper.make_bind_pose_local()

        # collect armature meshes
        root_helper.collect_armature_meshes()

        # find the correction matrices to align FBX objects with their Blender equivalent
        root_helper.find_correction_matrix(settings)

        # build the Object/Armature/Bone hierarchy
        root_helper.build_hierarchy(fbx_tmpl, settings, scene)

        # root_helper.print_info(0)
    _(); del _

    # We can handle shapes.
    blend_shape_channels = {}  # We do not need Shapes themselves, but keyblocks, for anim.

    def _():
        fbx_tmpl = fbx_template_get((b'Geometry', b'KFbxShape'))

        for s_uuid, s_item in fbx_table_nodes.items():
            fbx_sdata, bl_sdata = s_item = fbx_table_nodes.get(s_uuid, (None, None))
            if fbx_sdata is None or fbx_sdata.id != b'Geometry' or fbx_sdata.props[2] != b'Shape':
                continue

            # shape -> blendshapechannel -> blendshape -> mesh.
            for bc_uuid, bc_ctype in fbx_connection_map.get(s_uuid, ()):
                if bc_ctype.props[0] != b'OO':
                    continue
                fbx_bcdata, _bl_bcdata = fbx_table_nodes.get(bc_uuid, (None, None))
                if fbx_bcdata is None or fbx_bcdata.id != b'Deformer' or fbx_bcdata.props[2] != b'BlendShapeChannel':
                    continue
                meshes = []
                objects = []
                for bs_uuid, bs_ctype in fbx_connection_map.get(bc_uuid, ()):
                    if bs_ctype.props[0] != b'OO':
                        continue
                    fbx_bsdata, _bl_bsdata = fbx_table_nodes.get(bs_uuid, (None, None))
                    if fbx_bsdata is None or fbx_bsdata.id != b'Deformer' or fbx_bsdata.props[2] != b'BlendShape':
                        continue
                    for m_uuid, m_ctype in fbx_connection_map.get(bs_uuid, ()):
                        if m_ctype.props[0] != b'OO':
                            continue
                        fbx_mdata, bl_mdata = fbx_table_nodes.get(m_uuid, (None, None))
                        if fbx_mdata is None or fbx_mdata.id != b'Geometry' or fbx_mdata.props[2] != b'Mesh':
                            continue
                        # Blenmeshes are assumed already created at that time!
                        assert(isinstance(bl_mdata, bpy.types.Mesh))
                        # And we have to find all objects using this mesh!
                        objects = []
                        for o_uuid, o_ctype in fbx_connection_map.get(m_uuid, ()):
                            if o_ctype.props[0] != b'OO':
                                continue
                            node = fbx_helper_nodes[o_uuid]
                            if node:
                                objects.append(node)
                        meshes.append((bl_mdata, objects))
                    # BlendShape deformers are only here to connect BlendShapeChannels to meshes, nothing else to do.

                # keyblocks is a list of tuples (mesh, keyblock) matching that shape/blendshapechannel, for animation.
                keyblocks = blen_read_shape(fbx_tmpl, fbx_sdata, fbx_bcdata, meshes, scene)
                blend_shape_channels[bc_uuid] = keyblocks
    _(); del _

    # Animation!
    def _():
        fbx_tmpl_astack = fbx_template_get((b'AnimationStack', b'FbxAnimStack'))
        fbx_tmpl_alayer = fbx_template_get((b'AnimationLayer', b'FbxAnimLayer'))
        stacks = {}

        # AnimationStacks.
        for as_uuid, fbx_asitem in fbx_table_nodes.items():
            fbx_asdata, _blen_data = fbx_asitem
            if fbx_asdata.id != b'AnimationStack' or fbx_asdata.props[2] != b'':
                continue
            stacks[as_uuid] = (fbx_asitem, {})

        # AnimationLayers (mixing is completely ignored for now, each layer results in an independent set of actions).
        def get_astacks_from_alayer(al_uuid):
            for as_uuid, as_ctype in fbx_connection_map.get(al_uuid, ()):
                if as_ctype.props[0] != b'OO':
                    continue
                fbx_asdata, _bl_asdata = fbx_table_nodes.get(as_uuid, (None, None))
                if (fbx_asdata is None or fbx_asdata.id != b'AnimationStack' or
                    fbx_asdata.props[2] != b'' or as_uuid not in stacks):
                    continue
                yield as_uuid
        for al_uuid, fbx_alitem in fbx_table_nodes.items():
            fbx_aldata, _blen_data = fbx_alitem
            if fbx_aldata.id != b'AnimationLayer' or fbx_aldata.props[2] != b'':
                continue
            for as_uuid in get_astacks_from_alayer(al_uuid):
                _fbx_asitem, alayers = stacks[as_uuid]
                alayers[al_uuid] = (fbx_alitem, {})

        # AnimationCurveNodes (also the ones linked to actual animated data!).
        curvenodes = {}
        for acn_uuid, fbx_acnitem in fbx_table_nodes.items():
            fbx_acndata, _blen_data = fbx_acnitem
            if fbx_acndata.id != b'AnimationCurveNode' or fbx_acndata.props[2] != b'':
                continue
            cnode = curvenodes[acn_uuid] = {}
            items = []
            for n_uuid, n_ctype in fbx_connection_map.get(acn_uuid, ()):
                if n_ctype.props[0] != b'OP':
                    continue
                lnk_prop = n_ctype.props[3]
                if lnk_prop in {b'Lcl Translation', b'Lcl Rotation', b'Lcl Scaling'}:
                    # n_uuid can (????) be linked to root '0' node, instead of a mere object node... See T41712.
                    ob = fbx_helper_nodes.get(n_uuid, None)
                    if ob is None:
                        continue
                    items.append((ob, lnk_prop))
                elif lnk_prop == b'DeformPercent':  # Shape keys.
                    keyblocks = blend_shape_channels.get(n_uuid)
                    if keyblocks is None:
                        continue
                    items += [(kb, lnk_prop) for kb in keyblocks]
            for al_uuid, al_ctype in fbx_connection_map.get(acn_uuid, ()):
                if al_ctype.props[0] != b'OO':
                    continue
                fbx_aldata, _blen_aldata = fbx_alitem = fbx_table_nodes.get(al_uuid, (None, None))
                if fbx_aldata is None or fbx_aldata.id != b'AnimationLayer' or fbx_aldata.props[2] != b'':
                    continue
                for as_uuid in get_astacks_from_alayer(al_uuid):
                    _fbx_alitem, anim_items = stacks[as_uuid][1][al_uuid]
                    assert(_fbx_alitem == fbx_alitem)
                    for item, item_prop in items:
                        # No need to keep curvenode FBX data here, contains nothing useful for us.
                        anim_items.setdefault(item, {})[acn_uuid] = (cnode, item_prop)

        # AnimationCurves (real animation data).
        for ac_uuid, fbx_acitem in fbx_table_nodes.items():
            fbx_acdata, _blen_data = fbx_acitem
            if fbx_acdata.id != b'AnimationCurve' or fbx_acdata.props[2] != b'':
                continue
            for acn_uuid, acn_ctype in fbx_connection_map.get(ac_uuid, ()):
                if acn_ctype.props[0] != b'OP':
                    continue
                fbx_acndata, _bl_acndata = fbx_table_nodes.get(acn_uuid, (None, None))
                if (fbx_acndata is None or fbx_acndata.id != b'AnimationCurveNode' or
                    fbx_acndata.props[2] != b'' or acn_uuid not in curvenodes):
                    continue
                # Note this is an infamous simplification of the compound props stuff,
                # seems to be standard naming but we'll probably have to be smarter to handle more exotic files?
                channel = {b'd|X': 0, b'd|Y': 1, b'd|Z': 2, b'd|DeformPercent': 0}.get(acn_ctype.props[3], None)
                if channel is None:
                    continue
                curvenodes[acn_uuid][ac_uuid] = (fbx_acitem, channel)

        # And now that we have sorted all this, apply animations!
        blen_read_animations(fbx_tmpl_astack, fbx_tmpl_alayer, stacks, scene)

    _(); del _

    def _():
        # link Material's to Geometry (via Model's)
        for fbx_uuid, fbx_item in fbx_table_nodes.items():
            fbx_obj, blen_data = fbx_item
            if fbx_obj.id != b'Geometry':
                continue

            mesh = fbx_table_nodes.get(fbx_uuid, (None, None))[1]

            # can happen in rare cases
            if mesh is None:
                continue

            for (fbx_lnk,
                 fbx_lnk_item,
                 fbx_lnk_type) in connection_filter_forward(fbx_uuid, b'Model'):

                # link materials
                fbx_lnk_uuid = elem_uuid(fbx_lnk)
                for (fbx_lnk_material,
                     material,
                     fbx_lnk_material_type) in connection_filter_reverse(fbx_lnk_uuid, b'Material'):

                    mesh.materials.append(material)

            # We have to validate mesh polygons' mat_idx, see T41015!
            # Some FBX seem to have an extra 'default' material which is not defined in FBX file.
            if mesh.validate_material_indices():
                print("WARNING: mesh '%s' had invalid material indices, those were reset to first material" % mesh.name)
    _(); del _

    def _():
        material_images = {}

        fbx_tmpl = fbx_template_get((b'Material', b'KFbxSurfacePhong'))
        # b'KFbxSurfaceLambert'

        # textures that use this material
        def texture_bumpfac_get(fbx_obj):
            assert(fbx_obj.id == b'Material')
            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)
            # (x / 7.142) is only a guess, cycles usable range is (0.0 -> 0.5)
            return elem_props_get_number(fbx_props, b'BumpFactor', 2.5) / 7.142

        def texture_mapping_get(fbx_obj):
            assert(fbx_obj.id == b'Texture')

            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)
            return (elem_props_get_vector_3d(fbx_props, b'Translation', (0.0, 0.0, 0.0)),
                    elem_props_get_vector_3d(fbx_props, b'Rotation', (0.0, 0.0, 0.0)),
                    elem_props_get_vector_3d(fbx_props, b'Scaling', (1.0, 1.0, 1.0)),
                    (bool(elem_props_get_enum(fbx_props, b'WrapModeU', 0)),
                     bool(elem_props_get_enum(fbx_props, b'WrapModeV', 0))))

        if not use_cycles:
            # Simple function to make a new mtex and set defaults
            def material_mtex_new(material, image, tex_map):
                tex = texture_cache.get(image)
                if tex is None:
                    tex = bpy.data.textures.new(name=image.name, type='IMAGE')
                    tex.image = image
                    texture_cache[image] = tex

                    # copy custom properties from image object to texture
                    for key, value in image.items():
                        tex[key] = value

                    # delete custom properties on the image object
                    for key in image.keys():
                        del image[key]

                mtex = material.texture_slots.add()
                mtex.texture = tex
                mtex.texture_coords = 'UV'
                mtex.use_map_color_diffuse = False

                # No rotation here...
                mtex.offset[:] = tex_map[0]
                mtex.scale[:] = tex_map[2]
                return mtex

        for fbx_uuid, fbx_item in fbx_table_nodes.items():
            fbx_obj, blen_data = fbx_item
            if fbx_obj.id != b'Material':
                continue

            material = fbx_table_nodes.get(fbx_uuid, (None, None))[1]
            for (fbx_lnk,
                 image,
                 fbx_lnk_type) in connection_filter_reverse(fbx_uuid, b'Texture'):

                if use_cycles:
                    if fbx_lnk_type.props[0] == b'OP':
                        lnk_type = fbx_lnk_type.props[3]

                        ma_wrap = cycles_material_wrap_map[material]

                        # tx/rot/scale
                        tex_map = texture_mapping_get(fbx_lnk)
                        if (tex_map[0] == (0.0, 0.0, 0.0) and
                                tex_map[1] == (0.0, 0.0, 0.0) and
                                tex_map[2] == (1.0, 1.0, 1.0) and
                                tex_map[3] == (False, False)):
                            use_mapping = False
                        else:
                            use_mapping = True
                            tex_map_kw = {
                                "translation": tex_map[0],
                                "rotation": [-i for i in tex_map[1]],
                                "scale": [((1.0 / i) if i != 0.0 else 1.0) for i in tex_map[2]],
                                "clamp": tex_map[3],
                                }

                        if lnk_type == b'DiffuseColor':
                            ma_wrap.diffuse_image_set(image)
                            if use_mapping:
                                ma_wrap.diffuse_mapping_set(**tex_map_kw)
                        elif lnk_type == b'SpecularColor':
                            ma_wrap.specular_image_set(image)
                            if use_mapping:
                                ma_wrap.specular_mapping_set(**tex_map_kw)
                        elif lnk_type == b'ReflectionColor':
                            ma_wrap.reflect_image_set(image)
                            if use_mapping:
                                ma_wrap.reflect_mapping_set(**tex_map_kw)
                        elif lnk_type == b'TransparentColor':  # alpha
                            ma_wrap.alpha_image_set(image)
                            if use_mapping:
                                ma_wrap.alpha_mapping_set(**tex_map_kw)
                            if use_alpha_decals:
                                material_decals.add(material)
                        elif lnk_type == b'DiffuseFactor':
                            pass  # TODO
                        elif lnk_type == b'ShininessExponent':
                            ma_wrap.hardness_image_set(image)
                            if use_mapping:
                                ma_wrap.hardness_mapping_set(**tex_map_kw)
                        elif lnk_type == b'NormalMap' or lnk_type == b'Bump':  # XXX, applications abuse bump!
                            ma_wrap.normal_image_set(image)
                            ma_wrap.normal_factor_set(texture_bumpfac_get(fbx_obj))
                            if use_mapping:
                                ma_wrap.normal_mapping_set(**tex_map_kw)
                            """
                        elif lnk_type == b'Bump':
                            ma_wrap.bump_image_set(image)
                            ma_wrap.bump_factor_set(texture_bumpfac_get(fbx_obj))
                            if use_mapping:
                                ma_wrap.bump_mapping_set(**tex_map_kw)
                            """
                        else:
                            print("WARNING: material link %r ignored" % lnk_type)

                        material_images.setdefault(material, {})[lnk_type] = (image, tex_map)
                else:
                    if fbx_lnk_type.props[0] == b'OP':
                        lnk_type = fbx_lnk_type.props[3]

                        # tx/rot/scale (rot is ignored here!).
                        tex_map = texture_mapping_get(fbx_lnk)

                        mtex = material_mtex_new(material, image, tex_map)

                        if lnk_type == b'DiffuseColor':
                            mtex.use_map_color_diffuse = True
                            mtex.blend_type = 'MULTIPLY'
                        elif lnk_type == b'SpecularColor':
                            mtex.use_map_color_spec = True
                            mtex.blend_type = 'MULTIPLY'
                        elif lnk_type == b'ReflectionColor':
                            mtex.use_map_raymir = True
                        elif lnk_type == b'TransparentColor':  # alpha
                            material.use_transparency = True
                            material.transparency_method = 'RAYTRACE'
                            material.alpha = 0.0
                            mtex.use_map_alpha = True
                            mtex.alpha_factor = 1.0
                            if use_alpha_decals:
                                material_decals.add(material)
                        elif lnk_type == b'DiffuseFactor':
                            mtex.use_map_diffuse = True
                        elif lnk_type == b'ShininessExponent':
                            mtex.use_map_hardness = True
                        elif lnk_type == b'NormalMap' or lnk_type == b'Bump':  # XXX, applications abuse bump!
                            mtex.texture.use_normal_map = True  # not ideal!
                            mtex.use_map_normal = True
                            mtex.normal_factor = texture_bumpfac_get(fbx_obj)
                            """
                        elif lnk_type == b'Bump':
                            mtex.use_map_normal = True
                            mtex.normal_factor = texture_bumpfac_get(fbx_obj)
                            """
                        else:
                            print("WARNING: material link %r ignored" % lnk_type)

                        material_images.setdefault(material, {})[lnk_type] = (image, tex_map)

        # Check if the diffuse image has an alpha channel,
        # if so, use the alpha channel.

        # Note: this could be made optional since images may have alpha but be entirely opaque
        for fbx_uuid, fbx_item in fbx_table_nodes.items():
            fbx_obj, blen_data = fbx_item
            if fbx_obj.id != b'Material':
                continue
            material = fbx_table_nodes.get(fbx_uuid, (None, None))[1]
            image, tex_map = material_images.get(material, {}).get(b'DiffuseColor', (None, None))
            # do we have alpha?
            if image and image.depth == 32:
                if use_alpha_decals:
                    material_decals.add(material)

                if use_cycles:
                    ma_wrap = cycles_material_wrap_map[material]
                    if ma_wrap.node_bsdf_alpha.mute:
                        ma_wrap.alpha_image_set_from_diffuse()
                else:
                    if not any((True for mtex in material.texture_slots if mtex and mtex.use_map_alpha)):
                        mtex = material_mtex_new(material, image, tex_map)

                        material.use_transparency = True
                        material.transparency_method = 'RAYTRACE'
                        material.alpha = 0.0
                        mtex.use_map_alpha = True
                        mtex.alpha_factor = 1.0

            # propagate mapping from diffuse to all other channels which have none defined.
            if use_cycles:
                ma_wrap = cycles_material_wrap_map[material]
                ma_wrap.mapping_set_from_diffuse()

    _(); del _

    def _():
        # Annoying workaround for cycles having no z-offset
        if material_decals and use_alpha_decals:
            for fbx_uuid, fbx_item in fbx_table_nodes.items():
                fbx_obj, blen_data = fbx_item
                if fbx_obj.id != b'Geometry':
                    continue
                if fbx_obj.props[-1] == b'Mesh':
                    mesh = fbx_item[1]

                    if decal_offset != 0.0:
                        for material in mesh.materials:
                            if material in material_decals:
                                for v in mesh.vertices:
                                    v.co += v.normal * decal_offset
                                break

                    if use_cycles:
                        for obj in (obj for obj in bpy.data.objects if obj.data == mesh):
                            obj.cycles_visibility.shadow = False
                    else:
                        for material in mesh.materials:
                            if material in material_decals:
                                # recieve but dont cast shadows
                                material.use_raytrace = False
    _(); del _

    print('Import finished in %.4f sec.' % (time.process_time() - start_time))
    return {'FINISHED'}