Assassin's Creed: Odyssey Research

How to interpret this documentation

• Forgive me if this documentation is confusing. This is my first time doing this.
• If a struct has been spelt out, it will not be repeated. Use the links to jump to that struct.

Notes

• In the raw data extracted from the forge, you should take each Data Chunk data, decompress it, and merge it with the other decompressed data. This is because the maximum decompressed data size for each Data Chunk is 262144 bytes (0x00 0x00 0x04 0x00).
• THIS DOCUMENTATION IS UNFINISHED.

Compression

Oodle

Header

Type	Name	Size	Notes
Resource Type	resourceType	4
int	fileSize	4
int	fileNameSize	4
char[]	fileName	fileNameSize
	<skip 2 bytes>
int64	fileID	8	fileID is the same from this file's entry in the .forge Index Table

---

Resource Type

This is always found at the first 4 bytes of decompressed data. Other Resource Types can appear in the same file, for example, in mesh files. Here is a selection of the most important Resource Types.

These values are actually strings (names of the Resource Type without spaces) hashed with CRC32.

Value	Resource Type
0xFC9E1595	Compiled Mesh
0x85C817C3	Material
0x415D9568	Mesh
0x1D4B87A3	Mipmap
0x24AECB7C	Skeleton
0xA2B7E917	Texture Map
0xD70E6670	Texture Set

---

DXT

Whatever you call it, DXT Type, DXT compression, fourCC, etc.

Value	DXT
0, 7	DXT0
1, 2, 3	DXT1
4	DXT3
5, 6, 12	DXT5
8, 9, 16	DX10

---

Texture Map file

Structure

• Header
• Texture Map
• Image Data

TopMip

Type	Name	Size (bytes)
int	width	4
int	height	4
	<skip 8 bytes>
DXT	dxt	4
	<skip 4 bytes>
int	mipmaps	4

Texture Map

Type	Name	Size (bytes)
int	fileType	4
TopMip	topMip0	28
	<skip 81 bytes>
TopMip	topMip1	28
	<skip 25 bytes>

Image Data

Type	Name	Size (bytes)
int	imageDataSize	4
byte[]	imageData	imageDataSize

---

TopMip file

Structure

• Header
• Image Data Alt

Image Data Alt

This is different than the Image Data block above. This one lacks an int before the imageData.

Type	Name	Size (bytes)	Notes
byte[]	imageData	fileSize	fileSize from the Header