luanti/doc/world_format.txt

=============================
Minetest World Format 22...29
=============================

This applies to a world format carrying the block serialization version
22...27, used at least in
- 0.4.dev-20120322 ... 0.4.dev-20120606 (22...23)
- 0.4.0 (23)
- 24 was never released as stable and existed for ~2 days
- 27 was added in 0.4.15-dev
- 29 was added in 5.5.0-dev

The block serialization version does not fully specify every aspect of this
format; if compliance with this format is to be checked, it needs to be
done by detecting if the files and data indeed follows it.

Files
======
Everything is contained in a directory, the name of which is freeform, but
often serves as the name of the world.

Currently the authentication and ban data is stored on a per-world basis.
It can be copied over from an old world to a newly created world.

World
|-- auth.txt ----- Authentication data
|-- auth.sqlite -- Authentication data (SQLite alternative)
|-- env_meta.txt - Environment metadata
|-- ipban.txt ---- Banned ips/users
|-- map_meta.txt - Map metadata
|-- map.sqlite --- Map data
|-- players ------ Player directory
|   |-- player1 -- Player file
|   '-- Foo ------ Player file
`-- world.mt ----- World metadata

auth.txt
---------
Contains authentication data, player per line.
  <name>:<password hash>:<privilege1,...>

Legacy format (until 0.4.12) of password hash is <name><password> SHA1'd,
in the base64 encoding.

Format (since 0.4.13) of password hash is #1#<salt>#<verifier>, with the
parts inside <> encoded in the base64 encoding.
<verifier> is an RFC 2945 compatible SRP verifier,
of the given salt, password, and the player's name lowercased,
using the 2048-bit group specified in RFC 5054 and the SHA-256 hash function.

Example lines:
- Player "celeron55", no password, privileges "interact" and "shout":
    celeron55::interact,shout
- Player "Foo", password "bar", privilege "shout", with a legacy password hash:
    foo:iEPX+SQWIR3p67lj/0zigSWTKHg:shout
- Player "Foo", password "bar", privilege "shout", with a 0.4.13 pw hash:
    foo:#1#hPpy4O3IAn1hsNK00A6wNw#Kpu6rj7McsrPCt4euTb5RA5ltF7wdcWGoYMcRngwDi11cZhPuuR9i5Bo7o6A877TgcEwoc//HNrj9EjR/CGjdyTFmNhiermZOADvd8eu32FYK1kf7RMC0rXWxCenYuOQCG4WF9mMGiyTPxC63VAjAMuc1nCZzmy6D9zt0SIKxOmteI75pAEAIee2hx4OkSXRIiU4Zrxo1Xf7QFxkMY4x77vgaPcvfmuzom0y/fU1EdSnZeopGPvzMpFx80ODFx1P34R52nmVl0W8h4GNo0k8ZiWtRCdrJxs8xIg7z5P1h3Th/BJ0lwexpdK8sQZWng8xaO5ElthNuhO8UQx1l6FgEA:shout
- Player "bar", no password, no privileges:
    bar::

auth.sqlite
------------
Contains authentification data as an SQLite database. This replaces auth.txt
above when auth_backend is set to "sqlite3" in world.mt .

This database contains two tables "auth" and "user_privileges":

CREATE TABLE `auth` (
  `id` INTEGER PRIMARY KEY AUTOINCREMENT,
  `name` VARCHAR(32) UNIQUE,
  `password` VARCHAR(512),
  `last_login` INTEGER
);
CREATE TABLE `user_privileges` (
  `id` INTEGER,
  `privilege` VARCHAR(32),
  PRIMARY KEY (id, privilege)
  CONSTRAINT fk_id FOREIGN KEY (id) REFERENCES auth (id) ON DELETE CASCADE
);

The "name" and "password" fields of the auth table are the same as the auth.txt
fields (with modern password hash). The "last_login" field is the last login
time as a unix time stamp.

The "user_privileges" table contains one entry per privilege and player.
A player with "interact" and "shout" privileges will have two entries, one
with privilege="interact" and the second with privilege="shout".

env_meta.txt
-------------
Simple global environment variables.
Example content (added indentation):
  game_time = 73471
  time_of_day = 19118
  EnvArgsEnd

ipban.txt
----------
Banned IP addresses and usernames.
Example content (added indentation):
  123.456.78.9|foo
  123.456.78.10|bar

map_meta.txt
-------------
Simple global map variables.
Example content (added indentation):
  seed = 7980462765762429666
  [end_of_params]

map.sqlite
-----------
Map data.
See Map File Format below.

player1, Foo
-------------
Player data.
Filename can be anything.
See Player File Format below.

world.mt
---------
World metadata.
Example content (added indentation and - explanations):
  gameid = mesetint             - name of the game
  enable_damage = true          - whether damage is enabled or not
  creative_mode = false         - whether creative mode is enabled or not
  backend = sqlite3             - which DB backend to use for blocks (sqlite3, dummy, leveldb, redis, postgresql)
  player_backend = sqlite3      - which DB backend to use for player data
  readonly_backend = sqlite3    - optionally readonly seed DB (DB file _must_ be located in "readonly" subfolder)
  server_announce = false       - whether the server is publicly announced or not
  load_mod_<mod> = false        - whether <mod> is to be loaded in this world
  auth_backend = files          - which DB backend to use for authentication data

Player File Format
===================

- Should be pretty self-explanatory.
- Note: position is in nodes * 10

Example content (added indentation):
  hp = 11
  name = celeron55
  pitch = 39.77
  position = (-5231.97,15,1961.41)
  version = 1
  yaw = 101.37
  PlayerArgsEnd
  List main 32
  Item default:torch 13
  Item default:pick_steel 1 50112
  Item experimental:tnt
  Item default:cobble 99
  Item default:pick_stone 1 13104
  Item default:shovel_steel 1 51838
  Item default:dirt 61
  Item default:rail 78
  Item default:coal_lump 3
  Item default:cobble 99
  Item default:leaves 22
  Item default:gravel 52
  Item default:axe_steel 1 2045
  Item default:cobble 98
  Item default:sand 61
  Item default:water_source 94
  Item default:glass 2
  Item default:mossycobble
  Item default:pick_steel 1 64428
  Item animalmaterials:bone
  Item default:sword_steel
  Item default:sapling
  Item default:sword_stone 1 10647
  Item default:dirt 99
  Empty
  Empty
  Empty
  Empty
  Empty
  Empty
  Empty
  Empty
  EndInventoryList
  List craft 9
  Empty
  Empty
  Empty
  Empty
  Empty
  Empty
  Empty
  Empty
  Empty
  EndInventoryList
  List craftpreview 1
  Empty
  EndInventoryList
  List craftresult 1
  Empty
  EndInventoryList
  EndInventory

Map File Format
================

Minetest maps consist of MapBlocks, chunks of 16x16x16 nodes.

In addition to the bulk node data, MapBlocks stored on disk also contain
other things.

History
--------
We need a bit of history in here. Initially Minetest stored maps in a
format called the "sectors" format. It was a directory/file structure like
this:
  sectors2/XXX/ZZZ/YYYY
For example, the MapBlock at (0,1,-2) was this file:
  sectors2/000/ffd/0001

Eventually Minetest outgrow this directory structure, as filesystems were
struggling under the amount of files and directories.

Large servers seriously needed a new format, and thus the base of the
current format was invented, suggested by celeron55 and implemented by
JacobF.

SQLite3 was slammed in, and blocks files were directly inserted as blobs
in a single table, indexed by integer primary keys, oddly mangled from
coordinates.

Today we know that SQLite3 allows multiple primary keys (which would allow
storing coordinates separately), but the format has been kept unchanged for
that part. So, this is where it has come.
</history>

So here goes
-------------
map.sqlite is an sqlite3 database, containing a single table, called
"blocks". It looks like this:

  CREATE TABLE `blocks` (`pos` INT NOT NULL PRIMARY KEY,`data` BLOB);

The key
--------
"pos" is created from the three coordinates of a MapBlock using this
algorithm, defined here in Python:

  def getBlockAsInteger(p):
      return int64(p[2]*16777216 + p[1]*4096 + p[0])

  def int64(u):
      while u >= 2**63:
          u -= 2**64
      while u <= -2**63:
          u += 2**64
      return u

It can be converted the other way by using this code:

  def getIntegerAsBlock(i):
      x = unsignedToSigned(i % 4096, 2048)
      i = int((i - x) / 4096)
      y = unsignedToSigned(i % 4096, 2048)
      i = int((i - y) / 4096)
      z = unsignedToSigned(i % 4096, 2048)
      return x,y,z

  def unsignedToSigned(i, max_positive):
      if i < max_positive:
          return i
      else:
          return i - 2*max_positive

The blob
---------
The blob is the data that would have otherwise gone into the file.

See below for description.

MapBlock serialization format
==============================
NOTE: Byte order is MSB first (big-endian).
NOTE: Zlib data is in such a format that Python's zlib at least can
      directly decompress.
NOTE: Since version 29 zstd is used instead of zlib. In addition the entire
      block is first serialized and then compressed (except the version byte).

u8 version
- map format version number, see serialisation.h for the latest number

u8 flags
- Flag bitmasks:
  - 0x01: is_underground: Should be set to 0 if there will be no light
    obstructions above the block. If/when sunlight of a block is updated
    and there is no block above it, this value is checked for determining
    whether sunlight comes from the top.
  - 0x02: day_night_differs: Whether the lighting of the block is different
    on day and night. Only blocks that have this bit set are updated when
    day transforms to night.
  - 0x04: lighting_expired: Not used in version 27 and above. If true,
    lighting is invalid and should be updated.  If you can't calculate
    lighting in your generator properly, you could try setting this 1 to
    everything and setting the uppermost block in every sector as
    is_underground=0. I am quite sure it doesn't work properly, though.
  - 0x08: generated: True if the block has been generated. If false, block
    is mostly filled with CONTENT_IGNORE and is likely to contain eg. parts
    of trees of neighboring blocks.

u16 lighting_complete
- Added in version 27.
- This contains 12 flags, each of them corresponds to a direction.
- Indicates if the light is correct at the sides of a map block.
  Lighting may not be correct if the light changed, but a neighbor
  block was not loaded at that time.
  If these flags are false, Minetest will automatically recompute light
  when both this block and its required neighbor are loaded.
- The bit order is:
  nothing,  nothing,  nothing,  nothing,
  night X-, night Y-, night Z-, night Z+, night Y+, night X+,
  day X-,   day Y-,   day Z-,   day Z+,   day Y+,   day X+.
  Where 'day' is for the day light bank, 'night' is for the night
  light bank.
  The 'nothing' bits should be always set, as they will be used
  to indicate if direct sunlight spreading is finished.
- Example: if the block at (0, 0, 0) has
  lighting_complete = 0b1111111111111110,
  then Minetest will correct lighting in the day light bank when
  the block at (1, 0, 0) is also loaded.

if map format version >= 29:
  u32 timestamp
  - Timestamp when last saved, as seconds from starting the game.
  - 0xffffffff = invalid/unknown timestamp, nothing should be done with the time
                 difference when loaded

  u16 num_name_id_mappings
  foreach num_name_id_mappings
    u16 id
    u16 name_len
    u8[name_len] name
if map format version < 29:
  -- Nothing right here, timpstamp and node id mappings are serialized later

u8 content_width
- Number of bytes in the content (param0) fields of nodes
if map format version <= 23:
    - Always 1
if map format version >= 24:
    - Always 2

u8 params_width
- Number of bytes used for parameters per node
- Always 2

node data (zlib-compressed if version < 29):
if content_width == 1:
    - content:
      u8[4096]: param0 fields
      u8[4096]: param1 fields
      u8[4096]: param2 fields
if content_width == 2:
    - content:
      u16[4096]: param0 fields
      u8[4096]: param1 fields
      u8[4096]: param2 fields
- The location of a node in each of those arrays is (z*16*16 + y*16 + x).

node metadata list (zlib-compressed if version < 29):
- content:
  if map format version <= 22:
    u16 version (=1)
    u16 count of metadata
    foreach count:
      u16 position (p.Z*MAP_BLOCKSIZE*MAP_BLOCKSIZE + p.Y*MAP_BLOCKSIZE + p.X)
      u16 type_id
      u16 content_size
      u8[content_size] content of metadata. Format depends on type_id, see below.
  if map format version >= 23:
    u8 version -- Note: type was u16 for map format version <= 22
      -- = 1 for map format version < 28
      -- = 2 since map format version 28
    u16 count of metadata
    foreach count:
      u16 position (p.Z*MAP_BLOCKSIZE*MAP_BLOCKSIZE + p.Y*MAP_BLOCKSIZE + p.X)
      u32 num_vars
      foreach num_vars:
        u16 key_len
        u8[key_len] key
        u32 val_len
        u8[val_len] value
        u8 is_private -- only for version >= 2. 0 = not private, 1 = private
      serialized inventory

- Node timers
if map format version == 23:
  u8 unused version (always 0)
if map format version == 24: (NOTE: Not released as stable)
  u8 nodetimer_version
  if nodetimer_version == 0:
    (nothing else)
  if nodetimer_version == 1:
    u16 num_of_timers
    foreach num_of_timers:
      u16 timer position (z*16*16 + y*16 + x)
      s32 timeout*1000
      s32 elapsed*1000
if map format version >= 25:
  -- Nothing right here, node timers are serialized later

u8 static object version:
- Always 0

u16 static_object_count

foreach static_object_count:
  u8 type (object type-id)
  s32 pos_x_nodes * 10000
  s32 pos_y_nodes * 10000
  s32 pos_z_nodes * 10000
  u16 data_size
  u8[data_size] data

if map format version < 29:
  u32 timestamp
  - Same meaning as the timestamp further up

  u8 name-id-mapping version
  - Always 0

  u16 num_name_id_mappings
  foreach num_name_id_mappings
    u16 id
    u16 name_len
    u8[name_len] name

- Node timers
if map format version == 25:
  u8 length of the data of a single timer (always 2+4+4=10)
  u16 num_of_timers
  foreach num_of_timers:
    u16 timer position (z*16*16 + y*16 + x)
    s32 timeout*1000
    s32 elapsed*1000

EOF.

Format of nodes
----------------
A node is composed of the u8 fields param0, param1 and param2.

if map format version <= 23:
    The content id of a node is determined as so:
    - If param0 < 0x80,
        content_id = param0
    - Otherwise
        content_id = (param0<<4) + (param2>>4)
if map format version >= 24:
    The content id of a node is param0.

The purpose of param1 and param2 depend on the definition of the node.

The name-id-mapping
--------------------
The mapping maps node content ids to node names.

Node metadata format for map format versions <= 22
---------------------------------------------------
The node metadata are serialized depending on the type_id field.

1: Generic metadata
  serialized inventory
  u32 len
  u8[len] text
  u16 len
  u8[len] owner
  u16 len
  u8[len] infotext
  u16 len
  u8[len] inventory drawspec
  u8 allow_text_input (bool)
  u8 removal_disabled (bool)
  u8 enforce_owner (bool)
  u32 num_vars
  foreach num_vars
    u16 len
    u8[len] name
    u32 len
    u8[len] value

14: Sign metadata
  u16 text_len
  u8[text_len] text

15: Chest metadata
  serialized inventory

16: Furnace metadata
  TBD

17: Locked Chest metadata
  u16 len
  u8[len] owner
  serialized inventory

Static objects
---------------
Static objects are persistent freely moving objects in the world.

Object types:
1: Test object
7: LuaEntity

7: LuaEntity:
  u8 compatibility_byte (always 1)
  u16 len
  u8[len] entity name
  u32 len
  u8[len] static data
  s16 hp
  s32 velocity.x * 10000
  s32 velocity.y * 10000
  s32 velocity.z * 10000
  s32 yaw * 1000
  if PROTOCOL_VERSION >= 37:
    u8 version2 (=1)
    s32 pitch * 1000
    s32 roll * 1000

Itemstring format
------------------
eg. 'default:dirt 5'
eg. 'default:pick_wood 21323'
eg. '"default:apple" 2'
eg. 'default:apple'
- The wear value in tools is 0...65535
- There are also a number of older formats that you might stumble upon:
eg. 'node "default:dirt" 5'
eg. 'NodeItem default:dirt 5'
eg. 'ToolItem WPick 21323'

Inventory serialization format
-------------------------------
- The inventory serialization format is line-based
- The newline character used is "\n"
- The end condition of a serialized inventory is always "EndInventory\n"
- All the slots in a list must always be serialized.

Example (format does not include "---"):
---
List foo 4
Item default:sapling
Item default:sword_stone 1 10647
Item default:dirt 99
Empty
EndInventoryList
List bar 9
Empty
Empty
Empty
Empty
Empty
Empty
Empty
Empty
Empty
EndInventoryList
EndInventory
---