__init__.py

bl_info = {
    "name": "Import Panda3D .egg models",
    "author": "rdb, loonatic",
    "version": (2, 6, 0),
    "blender": (2, 80, 0),
    "location": "File > Import > Panda3D (.egg)",
    "description": "",
    "warning": "",
    "category": "Import-Export",
}

import bpy
if bpy.app.version < (2, 80):
    bl_info["blender"] = (2, 74, 0)  # Needed for normals_split_custom_set


if "loaded" in locals():
    import imp
    imp.reload(eggparser)
    imp.reload(importer)
else:
    from . import eggparser
    from . import importer

loaded = True

import os.path
import bpy.types
from bpy import props
from bpy_extras.io_utils import ImportHelper


class EggImporterPreferences(bpy.types.AddonPreferences):
    bl_idname = __name__

    if bpy.app.version >= (2, 80):
        backup_texpath: props.StringProperty(
            name = "Texture path",
            subtype = "FILE_PATH",
            description = "Backup texture path to check if the texture can't be "
                          "found at the location of the .egg"
        )
        want_bsdf: props.BoolProperty(
            name = "Use Principled BSDF",
            default = True,
            description = "Determines whether materials will automatically use Principled BSDF. "
                          "If false, they won't have shading"
        )
    else:
        backup_texpath = props.StringProperty(
            name="Texture path",
            subtype="FILE_PATH",
            description="Backup texture path to check if the texture can't be "
                        "found at the location of the .egg"
        )
        want_bsdf = props.BoolProperty(
            name="Use Principled BSDF",
            default=True,
            description="Determines whether materials will automatically use Principled BSDF. "
                        "If false, they won't have shading"
        )

    def draw(self, context):
        layout = self.layout
        layout.prop(self, "backup_texpath")
        layout.prop(self, "want_bsdf")


class IMPORT_OT_egg(bpy.types.Operator, ImportHelper):
    """Import .egg Operator"""
    bl_idname = "import_scene.egg"
    bl_label = "Import .egg"
    bl_description = "Import a Panda3D .egg file"
    bl_options = {'REGISTER', 'UNDO'}

    filename_ext = ".egg"
    filter_glob = props.StringProperty(default="*.egg;*.egg.pz;*.egg.gz", options={'HIDDEN'})

    """
    Note:
    Blender versions >= 2.8 use Python's type annotations (PEP 526), meaning we need to use colons instead of equals.
    If we do not use colons for >= 2.8, it may still run, but can spam the console with something like:
    rna_uiItemR: property not found: IMPORT_SCENE_OT_egg.auto_bind

    In <2.8 versions of Blender, we must use = for assigning custom properties, otherwise we will get a SyntaxError.
    """

    if bpy.app.version < (2, 80):
        directory = props.StringProperty(name="Directory", options={'HIDDEN'})
        files = props.CollectionProperty(type=bpy.types.OperatorFileListElement, options={'HIDDEN'})
    else:
        # Blender 2.79 still wants to compile this, however this syntax is considered invalid for this version.
        # To avoid a measly crash, let's just shrug off the syntax error for older versions.
        try:
            directory: props.StringProperty(name="Directory", options={'HIDDEN'})
            files: props.CollectionProperty(type=bpy.types.OperatorFileListElement, options={'HIDDEN'})
        except SyntaxError:
            pass

    if bpy.app.version >= (2, 80):
        load_external: props.BoolProperty(
            name = "Load external references",
            description = "Loads other .egg files referenced by this file as separate scenes, "
                          "and instantiates them using DupliGroups."
        )
        auto_bind: props.BoolProperty(
            name = "Auto bind",
            default = True,
            description = "Automatically tries to bind actions to armatures."
        )
    else:
        load_external = props.BoolProperty(
            name="Load external references",
            description="Loads other .egg files referenced by this file as separate scenes, "
                        "and instantiates them using DupliGroups."
        )
        auto_bind = props.BoolProperty(
            name="Auto bind",
            default=True,
            description="Automatically tries to bind actions to armatures."
        )

    def execute(self, context):
        context = importer.EggContext()
        context.info = lambda msg: self.report({'INFO'}, context.prefix_message(msg))
        context.warn = lambda msg: self.report({'WARNING'}, context.prefix_message(msg))
        context.error = lambda msg: self.report({'ERROR'}, context.prefix_message(msg))
        context.search_dir = self.directory
        roots = []

        for file in self.files:
            path = os.path.join(self.directory, file.name)
            root = context.read_file(path)
            roots.append(root)

        for root in roots:
            root.build_tree(context)
        context.assign_vertex_groups()

        if self.load_external:
            context.load_external_references()

        if self.auto_bind:
            context.auto_bind()

        context.final_report()
        return {'FINISHED'}

    def invoke(self, context, event):
        wm = context.window_manager
        wm.fileselect_add(self)
        return {'RUNNING_MODAL'}

    def draw(self, context):
        layout = self.layout
        row = layout.row()
        row.prop(self, "load_external")
        row = layout.row()
        row.prop(self, "auto_bind")


def menu_func(self, context):
    self.layout.operator(IMPORT_OT_egg.bl_idname, text = "Panda3D (.egg)")


def make_annotations(cls):
    """Converts class fields to annotations if running with Blender 2.8"""
    if bpy.app.version < (2, 80):
        return cls
    bl_props = {k: v for k, v in cls.__dict__.items() if isinstance(v, tuple)}
    if bl_props:
        if '__annotations__' not in cls.__dict__:
            setattr(cls, '__annotations__', {})
        annotations = cls.__dict__['__annotations__']
        for k, v in bl_props.items():
            annotations[k] = v
            delattr(cls, k)
    return cls

classes = (IMPORT_OT_egg, EggImporterPreferences)

def register():
    make_annotations(IMPORT_OT_egg)
    for cls in classes:
        bpy.utils.register_class(cls)

    if bpy.app.version >= (2, 80):
        bpy.types.TOPBAR_MT_file_import.append(menu_func)
    else:
        bpy.types.INFO_MT_file_import.append(menu_func)


def unregister():
    if bpy.app.version >= (2, 80):
        bpy.types.TOPBAR_MT_file_import.remove(menu_func)
    else:
        bpy.types.INFO_MT_file_import.remove(menu_func)

    for cls in classes:
        bpy.utils.unregister_class(cls)


if __name__ == "__main__":
    register()