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Binary serialization API¶
Introduction¶
Redot has a serialization API based on Variant. It's used for
converting data types to an array of bytes efficiently. This API is exposed
via the global bytes_to_var()
and var_to_bytes() functions,
but it is also used in the get_var
and store_var
methods of
FileAccess as well as the packet APIs for PacketPeer.
This format is not used for binary scenes and resources.
Full Objects vs Object instance IDs¶
If a variable is serialized with full_objects = true
, then any Objects
contained in the variable will be serialized and included in the result. This
is recursive.
If full_objects = false
, then only the instance IDs will be serialized for
any Objects contained in the variable.
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.
The lowest value two bytes are used to determine the type, while the highest value two bytes contain flags:
base_type = val & 0xFFFF;
flags = val >> 16;
Type |
Value |
---|---|
0 |
null |
1 |
bool |
2 |
integer |
3 |
float |
4 |
string |
5 |
vector2 |
6 |
rect2 |
7 |
vector3 |
8 |
transform2d |
9 |
plane |
10 |
quaternion |
11 |
aabb |
12 |
basis |
13 |
transform3d |
14 |
color |
15 |
node path |
16 |
rid |
17 |
object |
18 |
dictionary |
19 |
array |
20 |
raw array |
21 |
int32 array |
22 |
int64 array |
23 |
float32 array |
24 |
float64 array |
25 |
string array |
26 |
vector2 array |
27 |
vector3 array |
28 |
color array |
29 |
max |
Following this is the actual packet contents, which varies for each type of
packet. Note that this assumes Redot is compiled with single-precision floats,
which is the default. If Redot was compiled with double-precision floats, the
length of "Float" fields within data structures should be 8, and the offset
should be (offset - 4) * 2 + 4
. The "float" type itself always uses double
precision.
0: null¶
1: bool¶
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
4 |
Integer |
0 for False, 1 for True |
2: int¶
If no flags are set (flags == 0), the integer is sent as a 32 bit integer:
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
4 |
Integer |
32-bit signed integer |
If flag ENCODE_FLAG_64
is set (flags & 1 == 1
), the integer is sent as
a 64-bit integer:
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
8 |
Integer |
64-bit signed integer |
3: float¶
If no flags are set (flags == 0), the float is sent as a 32 bit single precision:
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
4 |
Float |
IEEE 754 single-precision float |
If flag ENCODE_FLAG_64
is set (flags & 1 == 1
), the float is sent as
a 64-bit double precision number:
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
8 |
Float |
IEEE 754 double-precision float |
4: 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: Vector2¶
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
4 |
Float |
X coordinate |
8 |
4 |
Float |
Y coordinate |
6: 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: Vector3¶
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
4 |
Float |
X coordinate |
8 |
4 |
Float |
Y coordinate |
12 |
4 |
Float |
Z coordinate |
8: Transform2D¶
Offset |
Len |
Type |
Description |
---|---|---|---|
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 |
Type |
Description |
---|---|---|---|
4 |
4 |
Float |
Normal X |
8 |
4 |
Float |
Normal Y |
12 |
4 |
Float |
Normal Z |
16 |
4 |
Float |
Distance |
10: Quaternion¶
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: 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: Basis¶
Offset |
Len |
Type |
Description |
---|---|---|---|
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: Transform3D¶
Offset |
Len |
Type |
Description |
---|---|---|---|
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 |
Type |
Description |
---|---|---|---|
4 |
4 |
Float |
Red (typically 0..1, can be above 1 for overbright colors) |
8 |
4 |
Float |
Green (typically 0..1, can be above 1 for overbright colors) |
12 |
4 |
Float |
Blue (typically 0..1, can be above 1 for overbright colors) |
16 |
4 |
Float |
Alpha (0..1) |
15: 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: RID (unsupported)¶
17: Object¶
An Object could be serialized in three different ways: as a null value, with
full_objects = false
, or with full_objects = true
.
A null value¶
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
4 |
Integer |
Zero (32-bit signed integer) |
full_objects
disabled¶
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
8 |
Integer |
The Object instance ID (64-bit signed integer) |
full_objects
enabled¶
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
4 |
Integer |
Class name (String length) |
8 |
X |
Bytes |
Class name (UTF-8 encoded string) |
X+8 |
4 |
Integer |
The number of properties that are serialized |
For each property:
Offset |
Len |
Type |
Description |
---|---|---|---|
Y |
4 |
Integer |
Property name (String length) |
Y+4 |
Z |
Bytes |
Property name (UTF-8 encoded string) |
Y+4+Z |
W |
<variable> |
Property value, using this same format |
Note
Not all properties are included. Only properties that are configured with the
PROPERTY_USAGE_STORAGE
flag set will be serialized. You can add a new usage flag to a property by overriding the
_get_property_list
method in your class. You can also check how property usage is configured by
calling Object._get_property_list
See
PropertyUsageFlags for the
possible usage flags.
18: 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: 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: PackedByteArray¶
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: PackedInt32Array¶
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
4 |
Integer |
Array length (Integers) |
8..8+length*4 |
4 |
Integer |
32-bit signed integer |
22: PackedInt64Array¶
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
8 |
Integer |
Array length (Integers) |
8..8+length*8 |
8 |
Integer |
64-bit signed integer |
23: PackedFloat32Array¶
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
4 |
Integer |
Array length (Floats) |
8..8+length*4 |
4 |
Integer |
32-bit IEEE 754 single-precision float |
24: PackedFloat64Array¶
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
4 |
Integer |
Array length (Floats) |
8..8+length*8 |
8 |
Integer |
64-bit IEEE 754 double-precision float |
25: PackedStringArray¶
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.
26: PackedVector2Array¶
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 |
27: PackedVector3Array¶
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 |
28: PackedColorArray¶
Offset |
Len |
Type |
Description |
---|---|---|---|
4 |
4 |
Integer |
Array length |
8..8+length*16 |
4 |
Float |
Red (typically 0..1, can be above 1 for overbright colors) |
8..12+length*16 |
4 |
Float |
Green (typically 0..1, can be above 1 for overbright colors) |
8..16+length*16 |
4 |
Float |
Blue (typically 0..1, can be above 1 for overbright colors) |
8..20+length*16 |
4 |
Float |
Alpha (0..1) |