save.py

import nbtlib as nbt
import base36
import chunk

class Save:
    def __init__(self, world, path = "save"):
        self.world = world
        self.path = path

    def chunk_position_to_path(self, chunk_position):
        x, y, z = chunk_position

        chunk_path = '/'.join((
            self.path,
            base36.dumps(x % 64),
            base36.dumps(z % 64),
            f"c.{base36.dumps(x)}.{base36.dumps(z)}.dat"
        ))

        return chunk_path

    def load_chunk(self, chunk_position):
        # load the chunk file
        chunk_path = self.chunk_position_to_path(chunk_position)

        try: chunk_blocks = nbt.load(chunk_path)["Level"]["Blocks"]
        except FileNotFoundError: return

        # create chunk and fill it with blocks from the chunk file

        self.world.chunks[chunk_position] = chunk.Chunk(self.world, chunk_position)

        for x in range(chunk.CHUNK_WIDTH):
            for y in range(chunk.CHUNK_HEIGHT):
                for z in range(chunk.CHUNK_LENGTH):
                    self.world.chunks[chunk_position].blocks[x][y][z] = chunk_blocks[
                        x * chunk.CHUNK_LENGTH * chunk.CHUNK_HEIGHT +
                        z * chunk.CHUNK_HEIGHT +
                        y
                    ]

    def load(self):
        for x in range(-4, 4):
            for z in range (-4, 4):
                self.load_chunk((x, 0, z))

    def save_chunk(self, chunk_position):
        x, y, z = chunk_position
        chunk_path = self.chunk_position_to_path(chunk_position)

        # if chunk cannot be loaded, create a new one
        try: chunk_data = nbt.load(chunk_path)
        except FileNotFoundError:
            chunk_data = nbt.File({"": nbt.Compound({"Level": nbt.Compound()})})
            
            chunk_data["Level"]["xPos"] = x
            chunk_data["Level"]["zPos"] = z

        # fill the chunk with blocks from our chunk

        chunk_blocks = nbt.ByteArray([0] * (chunk.CHUNK_WIDTH * chunk.CHUNK_HEIGHT * chunk.CHUNK_LENGTH))
        
        for x in range(chunk.CHUNK_WIDTH):
            for y in range(chunk.CHUNK_HEIGHT):
                for z in range(chunk.CHUNK_LENGTH):
                    chunk_blocks[
                        x * chunk.CHUNK_LENGTH * chunk.CHUNK_HEIGHT +
                        z * chunk.CHUNK_HEIGHT +
                        y
                    ] = self.world.chunks[chunk_position].blocks[x][y][z]
        
        # save the chunk file

        chunk_data["Level"]["Blocks"] = chunk_blocks
        chunk_data.save(chunk_path, gzipped = True) # save with compression


    def save(self):
        for chunk_position in self.world.chunks:
            if chunk_position[1] != 0: continue

            chunk = self.world.chunks[chunk_position]

            if chunk.modified:
                self.save_chunk(chunk_position)
                chunk.modified = False