Convert MCSharp .lvl savefiles to a format MCEdit understands

convert_mcsharp_to_mcedit.py

#!/usr/bin/env python 
import gzip
import os
import struct
import argparse

"""
This program converts save files from MCSharp (*.lvl) files to *.raw.lvl-files that MCEdit can understand.

The main use case for this is to further convert said saves to a Minecraft Release World.
"""


"""
The header of a MCSharp .lvl file is 18 bytes.

See https://github.com/Voziv/MCSharp/blob/master/MCSharp/World/Map.cs
"""
header_size = 18

"""
Maps all the MCSharp blocks to vanilla blocks. Each key is a MCSharp block and each value a vanilla block
See https://minecraft.gamepedia.com/Java_Edition_data_values/Classic for the existing blocks and 
https://github.com/Voziv/MCSharp/blob/master/MCSharp/World/Block.cs for the blocks that MCSharp uses
"""
conversions = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,
               29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 45, 4, 1, 1, 2, 3, 5,
               6, 12, 13, 14, 15, 16, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39,
               40, 41, 42, 43, 44, 46, 47, 48, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 20, 49, 45, 4, 1,
               0, 8, 0xff, 0xff, 0xff, 5, 5, 10, 49, 20, 36, 2, 3, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23,
               24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 46, 47, 48, 0xff, 0xff,
               0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
               0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
               0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0, 5, 0, 0, 0, 49, 20, 36, 36, 45, 4, 1, 1, 2, 3,
               5, 6, 12, 13, 14, 15, 16, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39,
               40, 41, 42, 44, 43, 46, 47, 48, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff]


def get_argument_parser():
    parser = argparse.ArgumentParser(description='Removes the custom blocks from the MCSharp level-format and saves it '
                                                 'in a format that MCEdit understands.')
    parser.add_argument(
        '--path',
        '-p',
        default=".",
        help="The directory in which to look for .lvl-files. Default is the working directory"
    )

    parser.add_argument(
        '--recursive',
        '-r',
        action='store_true',
        help="Also search for .lvl-files in subdirectories of the input-directory"
    )

    parser.add_argument(
        '--output',
        '-o',
        default=".",
        help="Store the output in the selected folder, default is to store it next to the original file"
    )

    return parser


def get_levels(path, recursive):
    """

    :param path: The path to look for .lvl-files
    :param recursive: Whether to look into subfolders
    :return: A list of paths to .lvl-files
    """
    if recursive:
        files = []

        for root, directories, filenames in os.walk(path):
            files.extend([os.path.join(root, file) for file in filenames])
    else:
        files = [file for file in os.listdir(path) if os.path.isfile(file)]

    # Filter out any fils that do not match .lvl (and are .raw.lvl => already converted)
    return [file for file in files if file[-3:] == "lvl" and file[-7:] != "raw.lvl"]


def get_level_size(level_data):
    """
    Read the size of the level from the header

    See https://github.com/Voziv/MCSharp/blob/master/MCSharp/World/Map.cs for more information on the map format

    :param level_data: The level data
    :return: A tuple containing the size in the following order: 1) width 2) length 3) height
    """
    level_data.seek(2)
    width = struct.unpack("H", level_data.read(2))[0]
    length = struct.unpack("H", level_data.read(2))[0]
    height = struct.unpack("H", level_data.read(2))[0]

    return width, length, height


def get_header(level_data):
    """
    Returns the first bytes that contain the header

    See https://github.com/Voziv/MCSharp/blob/master/MCSharp/World/Map.cs for more information on the map format

    :param level_data: The level data
    :return: The header
    """
    level_data.seek(0)
    return level_data.read(header_size)


def get_blocks(level_data):
    """
    Returns all the blocks that are stored in the map

    See https://github.com/Voziv/MCSharp/blob/master/MCSharp/World/Map.cs for more information on the map format

    :param level_data: The level data
    :return: A list containing all the blocks, each element is a block type
    """
    level_data.seek(header_size)

    size = get_level_size(level_data)
    length = size[0] * size[1] * size[2]
    return struct.unpack("B" * length, level_data.read(length))


def map_custom_blocks(blocks):
    """
    This method maps the custom blocks back to normal blocks

     See https://minecraft.gamepedia.com/Java_Edition_data_values/Classic for the existing blocks and
    https://github.com/Voziv/MCSharp/blob/master/MCSharp/World/Block.cs for the blocks that MCSharp uses
    :param blocks: The blocks to map
    :return: A list containing all the blocks where each element is a vanilla block
    """
    return [conversions[block] for block in blocks]


def save_level_raw(header, blocks, file):
    """
    Saves the header and blocks to the given file

    This saves the level in a raw format; no GZIP is used

    :param header: The header to save
    :param blocks: The blocks to save
    :param file: The file to save the headers and blocks to
    """
    with open(file, "wb") as level_data:
        level_data.write(header)
        level_data.write(struct.pack("B" * len(blocks), *blocks))


def convert_level(level_path, output):
    """
    Convert this level to a vanilla Minecraft Classic level
    :param level_path: The MCSharp level
    :param output: The output directory
    """
    print("Opening {0}".format(level_path))

    # Open the level through GZIP
    with gzip.open(level_path) as level_data:
        size = get_level_size(level_data)
        print("\tSize: w={}, h={}, l={}".format(size[0], size[1], size[2]))

        header = get_header(level_data)

        print("\tConverting blocks")
        blocks = map_custom_blocks(get_blocks(level_data))

        output_level_path = "{name} {width} {length} {height}.raw.lvl".format(
            name=level_path[:-4] if output is None else "{}/{}.raw.lvl".format(
                output,
                os.path.basename(level_path)
            ),
            width=size[0],
            length=size[1],
            height=size[2]
        )

        print("\tSaving converted level to {}".format(output_level_path))

        if os.path.isfile(output_level_path):
            print("\tWARNING: FILE ALREADY EXISTS, OVERWRITING")

        save_level_raw(header, blocks, output_level_path)

        print("\tDone")


def main():
    args = get_argument_parser().parse_args()

    if not args.output is None and not os.path.isdir(args.output):
        os.makedirs(args.output)

    for level_path in get_levels(args.path, args.recursive):
        convert_level(level_path, args.output)


if __name__ == "__main__":
    main()