Binary serialization API

Johdanto

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 File as well as the packet APIs for 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:

Tyyppi Arvo
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. Note that this assumes Godot is compiled with single precision floats. If instead doubles are used, the length of ”Float” fields within data structures should be 8, and the offset should be (offset - 4) * 2 + 4. The ”float” type itself is always double precision.

0: null

1: bool

Offset Len Tyyppi Kuvaus
4 4 Integer 0 for False, 1 for True

2: int

Offset Len Tyyppi Kuvaus
4 8 Integer Signed, 64-bit Integer

3: float

Offset Len Tyyppi Kuvaus
4 4 Float IEE 754 32-Bits Float

4: String

Offset Len Tyyppi Kuvaus
4 4 Integer String Length (in Bytes)
8 X Bytes UTF-8 Encoded String

This field is padded to 4 bytes.

5: Vector2

Offset Len Tyyppi Kuvaus
4 4 Float X Coordinate
8 4 Float Y Coordinate

6: Rect2

Offset Len Tyyppi Kuvaus
4 4 Float X Coordinate
8 4 Float Y Coordinate
12 4 Float X Size
16 4 Float Y Size

7: Vector3

Offset Len Tyyppi Kuvaus
4 4 Float X Coordinate
8 4 Float Y Coordinate
12 4 Float Z Coordinate

8: Transform2D

Offset Len Tyyppi Kuvaus
4 4 Float The X component of the X column vector, accessed via [0][0]
8 4 Float The Y component of the X column vector, accessed via [0][1]
12 4 Float The X component of the Y column vector, accessed via [1][0]
16 4 Float The Y component of the Y column vector, accessed via [1][1]
20 4 Float The X component of the origin vector, accessed via [2][0]
24 4 Float The Y component of the origin vector, accessed via [2][1]

9: Plane

Offset Len Tyyppi Kuvaus
4 4 Float Normal X
8 4 Float Normal Y
12 4 Float Normal Z
16 4 Float Distance

10: Quat

Offset Len Tyyppi Kuvaus
4 4 Float Imaginary X
8 4 Float Imaginary Y
12 4 Float Imaginary Z
16 4 Float Real W

11: AABB

Offset Len Tyyppi Kuvaus
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: Basis

Offset Len Tyyppi Kuvaus
4 4 Float The X component of the X column vector, accessed via [0][0]
8 4 Float The Y component of the X column vector, accessed via [0][1]
12 4 Float The Z component of the X column vector, accessed via [0][2]
16 4 Float The X component of the Y column vector, accessed via [1][0]
20 4 Float The Y component of the Y column vector, accessed via [1][1]
24 4 Float The Z component of the Y column vector, accessed via [1][2]
28 4 Float The X component of the Z column vector, accessed via [2][0]
32 4 Float The Y component of the Z column vector, accessed via [2][1]
36 4 Float The Z component of the Z column vector, accessed via [2][2]

13: Transform

Offset Len Tyyppi Kuvaus
4 4 Float The X component of the X column vector, accessed via [0][0]
8 4 Float The Y component of the X column vector, accessed via [0][1]
12 4 Float The Z component of the X column vector, accessed via [0][2]
16 4 Float The X component of the Y column vector, accessed via [1][0]
20 4 Float The Y component of the Y column vector, accessed via [1][1]
24 4 Float The Z component of the Y column vector, accessed via [1][2]
28 4 Float The X component of the Z column vector, accessed via [2][0]
32 4 Float The Y component of the Z column vector, accessed via [2][1]
36 4 Float The Z component of the Z column vector, accessed via [2][2]
40 4 Float The X component of the origin vector, accessed via [3][0]
44 4 Float The Y component of the origin vector, accessed via [3][1]
48 4 Float The Z component of the origin vector, accessed via [3][2]

14: Color

Offset Len Tyyppi Kuvaus
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: NodePath

Offset Len Tyyppi Kuvaus
4 4 Integer String Length, or New Format (val&0x80000000!=0 and NameCount=val&0x7FFFFFFF)

For old format:

Offset Len Tyyppi Kuvaus
8 X Bytes UTF-8 Encoded String

Padded to 4 bytes.

For new format:

Offset Len Tyyppi Kuvaus
4 4 Integer Sub-Name Count
8 4 Integer Flags (absolute: val&1 != 0 )

For each Name and Sub-Name

Offset Len Tyyppi Kuvaus
X+0 4 Integer String Length
X+4 X Bytes UTF-8 Encoded String

Every name string is padded to 4 bytes.

16: RID (unsupported)

17: Object (unsupported)

18: Dictionary

Offset Len Tyyppi Kuvaus
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: Array

Offset Len Tyyppi Kuvaus
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: PoolByteArray

Offset Len Tyyppi Kuvaus
4 4 Integer Array Length (Bytes)
8..8+length 1 Byte Byte (0..255)

The array data is padded to 4 bytes.

21: PoolIntArray

Offset Len Tyyppi Kuvaus
4 4 Integer Array Length (Integers)
8..8+length*4 4 Integer 32 Bits Signed Integer

22: PoolRealArray

Offset Len Tyyppi Kuvaus
4 4 Integer Array Length (Floats)
8..8+length*4 4 Integer 32 Bits IEEE 754 Float

23: PoolStringArray

Offset Len Tyyppi Kuvaus
4 4 Integer Array Length (Strings)

For each String:

Offset Len Tyyppi Kuvaus
X+0 4 Integer String Length
X+4 X Bytes UTF-8 Encoded String

Every string is padded to 4 bytes.

24: PoolVector2Array

Offset Len Tyyppi Kuvaus
4 4 Integer Array Length
8..8+length*8 4 Float X Coordinate
8..12+length*8 4 Float Y Coordinate

25: PoolVector3Array

Offset Len Tyyppi Kuvaus
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: PoolColorArray

Offset Len Tyyppi Kuvaus
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)