godot-docs/tutorials/misc/binary_serialization_api.rst

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.. _doc_binary_serialization_api:
Binary serialization API
========================
Introduction
------------
Godot has a simple serialization API based on Variant. It's used for
converting data types to an array of bytes efficiently. This API is used
in the functions ``get_var`` and ``store_var`` of :ref:`class_File`
as well as the packet APIs for :ref:`class_PacketPeer`. This format
is not used for binary scenes and resources.
Packet specification
--------------------
The packet is designed to be always padded to 4 bytes. All values are
little endian encoded. All packets have a 4 byte header representing an
integer, specifying the type of data:
+--------+--------------------------+
| Type | Value |
+========+==========================+
| 0 | null |
+--------+--------------------------+
| 1 | bool |
+--------+--------------------------+
| 2 | integer |
+--------+--------------------------+
| 3 | float |
+--------+--------------------------+
| 4 | string |
+--------+--------------------------+
| 5 | vector2 |
+--------+--------------------------+
| 6 | rect2 |
+--------+--------------------------+
| 7 | vector3 |
+--------+--------------------------+
| 8 | transform2d |
+--------+--------------------------+
| 9 | plane |
+--------+--------------------------+
| 10 | quat |
+--------+--------------------------+
| 11 | aabb |
+--------+--------------------------+
| 12 | basis |
+--------+--------------------------+
| 13 | transform |
+--------+--------------------------+
| 14 | color |
+--------+--------------------------+
| 15 | node path |
+--------+--------------------------+
| 16 | rid |
+--------+--------------------------+
| 17 | object |
+--------+--------------------------+
| 18 | dictionary |
+--------+--------------------------+
| 19 | array |
+--------+--------------------------+
| 20 | raw array |
+--------+--------------------------+
| 21 | int array |
+--------+--------------------------+
| 22 | real array |
+--------+--------------------------+
| 23 | string array |
+--------+--------------------------+
| 24 | vector2 array |
+--------+--------------------------+
| 25 | vector3 array |
+--------+--------------------------+
| 26 | color array |
+--------+--------------------------+
| 27 | max |
+--------+--------------------------+
Following this is the actual packet contents, which varies for each type
of packet:
0: null
~~~~~~~
1: :ref:`bool<class_bool>`
~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+-----------+---------------------------+
| Offset | Len | Type | Description |
+==========+=======+===========+===========================+
| 4 | 4 | Integer | 0 for False, 1 for True |
+----------+-------+-----------+---------------------------+
2: :ref:`int<class_int>`
~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+-----------+--------------------------+
| Offset | Len | Type | Description |
+==========+=======+===========+==========================+
| 4 | 4 | Integer | Signed, 32-Bit Integer |
+----------+-------+-----------+--------------------------+
3: :ref:`float<class_float>`/real
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+---------+-------------------------+
| Offset | Len | Type | Description |
+==========+=======+=========+=========================+
| 4 | 4 | Float | IEE 754 32-Bits Float |
+----------+-------+---------+-------------------------+
4: :ref:`String<class_string>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+-----------+----------------------------+
| Offset | Len | Type | Description |
+==========+=======+===========+============================+
| 4 | 4 | Integer | String Length (in Bytes) |
+----------+-------+-----------+----------------------------+
| 8 | X | Bytes | UTF-8 Encoded String |
+----------+-------+-----------+----------------------------+
This field is padded to 4 bytes.
5: :ref:`Vector2<class_vector2>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+---------+----------------+
| Offset | Len | Type | Description |
+==========+=======+=========+================+
| 4 | 4 | Float | X Coordinate |
+----------+-------+---------+----------------+
| 8 | 4 | Float | Y Coordinate |
+----------+-------+---------+----------------+
6: :ref:`Rect2<class_rect2>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+---------+----------------+
| Offset | Len | Type | Description |
+==========+=======+=========+================+
| 4 | 4 | Float | X Coordinate |
+----------+-------+---------+----------------+
| 8 | 4 | Float | Y Coordinate |
+----------+-------+---------+----------------+
| 12 | 4 | Float | X Size |
+----------+-------+---------+----------------+
| 16 | 4 | Float | Y Size |
+----------+-------+---------+----------------+
7: :ref:`Vector3<class_vector3>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+---------+----------------+
| Offset | Len | Type | Description |
+==========+=======+=========+================+
| 4 | 4 | Float | X Coordinate |
+----------+-------+---------+----------------+
| 8 | 4 | Float | Y Coordinate |
+----------+-------+---------+----------------+
| 12 | 4 | Float | Z Coordinate |
+----------+-------+---------+----------------+
8: :ref:`Transform2D<class_transform2d>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+---------+---------------+
| Offset | Len | Type | Description |
+==========+=======+=========+===============+
| 4 | 4 | Float | [0][0] |
+----------+-------+---------+---------------+
| 8 | 4 | Float | [0][1] |
+----------+-------+---------+---------------+
| 12 | 4 | Float | [1][0] |
+----------+-------+---------+---------------+
| 16 | 4 | Float | [1][1] |
+----------+-------+---------+---------------+
| 20 | 4 | Float | [2][0] |
+----------+-------+---------+---------------+
| 24 | 4 | Float | [2][1] |
+----------+-------+---------+---------------+
9: :ref:`Plane<class_plane>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+---------+---------------+
| Offset | Len | Type | Description |
+==========+=======+=========+===============+
| 4 | 4 | Float | Normal X |
+----------+-------+---------+---------------+
| 8 | 4 | Float | Normal Y |
+----------+-------+---------+---------------+
| 12 | 4 | Float | Normal Z |
+----------+-------+---------+---------------+
| 16 | 4 | Float | Distance |
+----------+-------+---------+---------------+
10: :ref:`Quat<class_quat>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+---------+---------------+
| Offset | Len | Type | Description |
+==========+=======+=========+===============+
| 4 | 4 | Float | Imaginary X |
+----------+-------+---------+---------------+
| 8 | 4 | Float | Imaginary Y |
+----------+-------+---------+---------------+
| 12 | 4 | Float | Imaginary Z |
+----------+-------+---------+---------------+
| 16 | 4 | Float | Real W |
+----------+-------+---------+---------------+
11: :ref:`AABB<class_aabb>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+---------+----------------+
| Offset | Len | Type | Description |
+==========+=======+=========+================+
| 4 | 4 | Float | X Coordinate |
+----------+-------+---------+----------------+
| 8 | 4 | Float | Y Coordinate |
+----------+-------+---------+----------------+
| 12 | 4 | Float | Z Coordinate |
+----------+-------+---------+----------------+
| 16 | 4 | Float | X Size |
+----------+-------+---------+----------------+
| 20 | 4 | Float | Y Size |
+----------+-------+---------+----------------+
| 24 | 4 | Float | Z Size |
+----------+-------+---------+----------------+
12: :ref:`Basis<class_basis>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+---------+---------------+
| Offset | Len | Type | Description |
+==========+=======+=========+===============+
| 4 | 4 | Float | [0][0] |
+----------+-------+---------+---------------+
| 8 | 4 | Float | [0][1] |
+----------+-------+---------+---------------+
| 12 | 4 | Float | [0][2] |
+----------+-------+---------+---------------+
| 16 | 4 | Float | [1][0] |
+----------+-------+---------+---------------+
| 20 | 4 | Float | [1][1] |
+----------+-------+---------+---------------+
| 24 | 4 | Float | [1][2] |
+----------+-------+---------+---------------+
| 28 | 4 | Float | [2][0] |
+----------+-------+---------+---------------+
| 32 | 4 | Float | [2][1] |
+----------+-------+---------+---------------+
| 36 | 4 | Float | [2][2] |
+----------+-------+---------+---------------+
13: :ref:`Transform<class_transform>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+---------+---------------+
| Offset | Len | Type | Description |
+==========+=======+=========+===============+
| 4 | 4 | Float | [0][0] |
+----------+-------+---------+---------------+
| 8 | 4 | Float | [0][1] |
+----------+-------+---------+---------------+
| 12 | 4 | Float | [0][2] |
+----------+-------+---------+---------------+
| 16 | 4 | Float | [1][0] |
+----------+-------+---------+---------------+
| 20 | 4 | Float | [1][1] |
+----------+-------+---------+---------------+
| 24 | 4 | Float | [1][2] |
+----------+-------+---------+---------------+
| 28 | 4 | Float | [2][0] |
+----------+-------+---------+---------------+
| 32 | 4 | Float | [2][1] |
+----------+-------+---------+---------------+
| 36 | 4 | Float | [2][2] |
+----------+-------+---------+---------------+
| 40 | 4 | Float | [3][0] |
+----------+-------+---------+---------------+
| 44 | 4 | Float | [3][1] |
+----------+-------+---------+---------------+
| 48 | 4 | Float | [3][2] |
+----------+-------+---------+---------------+
14: :ref:`Color<class_color>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+---------+----------------+
| Offset | Len | Type | Description |
+==========+=======+=========+================+
| 4 | 4 | Float | Red (0..1) |
+----------+-------+---------+----------------+
| 8 | 4 | Float | Green (0..1) |
+----------+-------+---------+----------------+
| 12 | 4 | Float | Blue (0..1) |
+----------+-------+---------+----------------+
| 16 | 4 | Float | Alpha (0..1) |
+----------+-------+---------+----------------+
15: :ref:`NodePath<class_nodepath>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+-----------+-----------------------------------------------------------------------------------------+
| Offset | Len | Type | Description |
+==========+=======+===========+=========================================================================================+
| 4 | 4 | Integer | String Length, or New Format (val&0x80000000!=0 and NameCount=val&0x7FFFFFFF) |
+----------+-------+-----------+-----------------------------------------------------------------------------------------+
For old format:
^^^^^^^^^^^^^^^
+----------+-------+---------+------------------------+
| Offset | Len | Type | Description |
+==========+=======+=========+========================+
| 8 | X | Bytes | UTF-8 Encoded String |
+----------+-------+---------+------------------------+
Padded to 4 bytes.
For new format:
^^^^^^^^^^^^^^^
+----------+-------+-----------+-------------------------------------+
| Offset | Len | Type | Description |
+==========+=======+===========+=====================================+
| 4 | 4 | Integer | Sub-Name Count |
+----------+-------+-----------+-------------------------------------+
| 8 | 4 | Integer | Flags (absolute: val&1 != 0 ) |
+----------+-------+-----------+-------------------------------------+
For each Name and Sub-Name
+----------+-------+-----------+------------------------+
| Offset | Len | Type | Description |
+==========+=======+===========+========================+
| X+0 | 4 | Integer | String Length |
+----------+-------+-----------+------------------------+
| X+4 | X | Bytes | UTF-8 Encoded String |
+----------+-------+-----------+------------------------+
Every name string is padded to 4 bytes.
16: :ref:`RID<class_rid>` (unsupported)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
17: :ref:`Object<class_object>` (unsupported)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
18: :ref:`Dictionary<class_dictionary>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+-----------+---------------------------------------------------------------------+
| Offset | Len | Type | Description |
+==========+=======+===========+=====================================================================+
| 4 | 4 | Integer | val&0x7FFFFFFF = elements, val&0x80000000 = shared (bool) |
+----------+-------+-----------+---------------------------------------------------------------------+
Then what follows is, for amount of "elements", pairs of key and value,
one after the other, using this same format.
19: :ref:`Array<class_array>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+-----------+---------------------------------------------------------------------+
| Offset | Len | Type | Description |
+==========+=======+===========+=====================================================================+
| 4 | 4 | Integer | val&0x7FFFFFFF = elements, val&0x80000000 = shared (bool) |
+----------+-------+-----------+---------------------------------------------------------------------+
Then what follows is, for amount of "elements", values one after the
other, using this same format.
20: :ref:`PoolByteArray<class_poolbytearray>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+---------------+-------+-----------+------------------------+
| Offset | Len | Type | Description |
+===============+=======+===========+========================+
| 4 | 4 | Integer | Array Length (Bytes) |
+---------------+-------+-----------+------------------------+
| 8..8+length | 1 | Byte | Byte (0..255) |
+---------------+-------+-----------+------------------------+
The array data is padded to 4 bytes.
21: :ref:`PoolIntArray<class_poolintarray>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+------------------+-------+-----------+---------------------------+
| Offset | Len | Type | Description |
+==================+=======+===========+===========================+
| 4 | 4 | Integer | Array Length (Integers) |
+------------------+-------+-----------+---------------------------+
| 8..8+length\*4 | 4 | Integer | 32 Bits Signed Integer |
+------------------+-------+-----------+---------------------------+
22: :ref:`PoolRealArray<class_poolrealarray>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+------------------+-------+-----------+---------------------------+
| Offset | Len | Type | Description |
+==================+=======+===========+===========================+
| 4 | 4 |Integer | Array Length (Floats) |
+------------------+-------+-----------+---------------------------+
| 8..8+length\*4 | 4 |Integer | 32 Bits IEE 754 Float |
+------------------+-------+-----------+---------------------------+
23: :ref:`PoolStringArray<class_poolstringarray>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+----------+-------+-----------+--------------------------+
| Offset | Len | Type | Description |
+==========+=======+===========+==========================+
| 4 | 4 | Integer | Array Length (Strings) |
+----------+-------+-----------+--------------------------+
For each String:
+----------+-------+-----------+------------------------+
| Offset | Len | Type | Description |
+==========+=======+===========+========================+
| X+0 | 4 | Integer | String Length |
+----------+-------+-----------+------------------------+
| X+4 | X | Bytes | UTF-8 Encoded String |
+----------+-------+-----------+------------------------+
Every string is padded to 4 bytes.
24: :ref:`PoolVector2Array<class_poolvector2array>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+-------------------+-------+-----------+----------------+
| Offset | Len | Type | Description |
+===================+=======+===========+================+
| 4 | 4 | Integer | Array Length |
+-------------------+-------+-----------+----------------+
| 8..8+length\*8 | 4 | Float | X Coordinate |
+-------------------+-------+-----------+----------------+
| 8..12+length\*8 | 4 | Float | Y Coordinate |
+-------------------+-------+-----------+----------------+
25: :ref:`PoolVector3Array<class_poolvector3array>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+--------------------+-------+-----------+----------------+
| Offset | Len | Type | Description |
+====================+=======+===========+================+
| 4 | 4 | Integer | Array Length |
+--------------------+-------+-----------+----------------+
| 8..8+length\*12 | 4 | Float | X Coordinate |
+--------------------+-------+-----------+----------------+
| 8..12+length\*12 | 4 | Float | Y Coordinate |
+--------------------+-------+-----------+----------------+
| 8..16+length\*12 | 4 | Float | Z Coordinate |
+--------------------+-------+-----------+----------------+
26: :ref:`PoolColorArray<class_poolcolorarray>`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+--------------------+-------+-----------+----------------+
| Offset | Len | Type | Description |
+====================+=======+===========+================+
| 4 | 4 | Integer | Array Length |
+--------------------+-------+-----------+----------------+
| 8..8+length\*16 | 4 | Float | Red (0..1) |
+--------------------+-------+-----------+----------------+
| 8..12+length\*16 | 4 | Float | Green (0..1) |
+--------------------+-------+-----------+----------------+
| 8..16+length\*16 | 4 | Float | Blue (0..1) |
+--------------------+-------+-----------+----------------+
| 8..20+length\*16 | 4 | Float | Alpha (0..1) |
+--------------------+-------+-----------+----------------+