Sending a chunk

[Simetraa]

Hello,

I'm trying to write a very stripped down minecraft server with this library. However, I'm struggling to determine the cause of an error I get when trying to send a chunk to the client. My code so far is adapted from the examples, previous issues (#70) and PyMine's Packets.py (although I could not get that to run either)

Internal Exception: io.netty.handler.codac.DecoderException: java.io.IOException: Packet 0/34 (nf) was larger than I expected, found 27836 bytes extra whilst reading packet 34. Changing the region file seems to change the number of extra bytes, but not the packet number. The only similar issue I could find was #82, and I don't really understand what the fix was in that case.

x, z = 0, 0
with RegionFile("regionfile3.mca") as f:
    chunk = f.load_chunk(0, 0).body.value["Level"].value
full = chunk["Status"].value == "full"
registry = LookupRegistry.from_json("reports")

sections = [None] * 16
for section in chunk["Sections"].value:
    if 'Palette' in section.value:
        y = section.value["Y"].value
        if 0 <= y < 16:
            blocks = BlockArray.from_nbt(section, registry)
            block_light = None
            sky_light = None
            sections[y] = (blocks, block_light, sky_light)

heightmap = TagRoot.from_body(chunk["Heightmaps"]) # put in tagroot
biomes = chunk["Biomes"].value
block_entities = chunk["TileEntities"].value
sections_data = self.buff_type.pack_chunk(sections)
self.send_packet(
    'chunk_data',
    self.buff_type.pack('ii?', x, z, full), # int, int, bool
    self.buff_type.pack_chunk_bitmask(sections), # [optional?[blockarray]
    self.buff_type.pack_nbt(heightmap),  # TagRoot[TagCompound[TagLongArray[PackedArray]]]
    self.buff_type.pack_array('I', biomes) if full else b'', # []
    # changed in 1.15
    self.buff_type.pack_varint(len(sections_data)), sections_data, #?
    self.buff_type.pack_varint(len(block_entities)), # int
    b''.join(self.buff_type.pack_nbt(entity) for entity in block_entities)) # nbt list

[barneygale]

Sorrry for the long delay here. Did you still need a hand?

[Simetraa]

Yes please, that would be helpful.

[barneygale]

Which Minecraft version are you using?

[ajh123]

im using 1.16.3 and have the same problem

[barneygale]

Will try to work up an example!

[ajh123]

@barneygale How far done are. you with the example?

[tmshader]

Hey there! Is the example coming long? Or does anyone have a working script?

[ajh123]

i dont sadly, seems like no one dose

[tmshader]

Soon I'll have one! I just have to figure out how to read chunks from files. (I might be able to post the example in 2 days) :)

[ajh123]

@TMShader What’s your progress with the example?

[tmshader]

@ajh123 I'm sorry, I forgot to post it, but I can't post it sooner than a week, but as soon as I can I will. I was trying to make it faster and better, but reading and sending a chunk to a player takes about a second :( So don't expect some blazing fast code

[ajh123]

Thank you!

[ajh123]

@TMShader how good and fast is the example now?

[tmshader]

@ajh123 I tried generating it from code or reading it from file, but still slow :( I tried multithreading but nope I'm not sure what could make it better If I can't make it better/faster in a few days I'll extract the code from my testing code and post it here

[ajh123]

Thank you!

[ajh123]

@TMShader maybe a cache could make it faster for chunks that have not changed and are loaded

[tmshader]

@ajh123 i think the packet creation is slow so I could cache the packets maybe... Not sure, I'll try both ways tho, thanks for the help!

[ajh123]

@TMShader how much has the cache helped?

[tmshader]

@ajh123 I haven't had time to try it yet, but I'll do it as soon as possible

[ajh123]

@TMShader will this support 1.17 to

[tmshader]

@ajh123 I'm working on that rn but something changed that is not documented on wiki.vg :/

[ajh123]

ye, like the 3d biomes and like that

[ajh123]

we can look at bukkit / spigot to see how they do it and make it work in python

[tmshader]

@ajh123 I think I found why the code I used in 1.16.5 fails in 1.17.1. Instead of sending a VarInt for the Primary Bit Mask, 1.17 now sends an Array of Long which I have no idea how to implement yet. Therefore the ServerProtocol.buff_type.pack_chunk_bitmask() is outdated and has to be updated. @barneygale Any idea on how that could be implemented or what the right function should be?

[tmshader]

(And also, 1.17 uses a BitSet instead of a Bitmask)

[tmshader]

So I couldn't get the 1.17.1 version to work, but I have an example that I will upload to github soon. I tried storing the region files and the chunks, but the sending is slow. The example is multithreaded and sends the spawn chunk, then leaves the chunks sorrounding it empty and then sends the sorrounding chunks of the empty chunks.

It looks like this from above:

▮▮▮▮▮
▮▯▯▯▮
▮▯▮▯▮
▮▯▯▯▮
▮▮▮▮▮

[tmshader]

Ok the example is up, you can find it here @ajh123 https://github.com/TMShader/QuarryMinecraftServerTests

Edit: I've set up a server on 3rd.tmshader.me if anyone wants to try it

[ajh123]

yaaa, now the original issuer (@Simetraa ) needs to try it

[Simetraa]

Awesome! I can confirm it works. Thank you very much for your help. A new issue should probably be opened for the 1.17 problem? I'll close this one for now.