WADs are archives used by the clients. They contain assets, game data (e.g. item description), files for the LCU's interface and more.
The WAD file starts with the following header:
| Pos | Size | Format | Description |
|---|---|---|---|
| 0 | 2 | RW |
magic code |
| 2 | 1 | u8 | major version |
| 3 | 1 | u8 | minor version |
Parsing of following data depends on the major version. Latest known major version is 3.
Following the WAD header is the directory entry.
| Pos | Size | Format | Description |
|---|---|---|---|
| 0 | 2 | u16 | entry header offset |
| 2 | 2 | u16 | entry header size |
| 4 | 4 | u32 | entry count |
This header provides the number and location of entries in the WAD archive. Entry headers start at the entry header offset and are spaced by the entry header size. (In practice, they immediately follow the directory header and are contiguous.)
Following the WAD header is the directory entry.
| Pos | Size | Format | Description |
|---|---|---|---|
| 0 | 1 | u8 | ECDSA signature length |
| 1 | 83 | ECDSA signature of entry headers, padded with 0 |
|
| 84 | 8 | XXH64 checksum | |
| 92 | 2 | u16 | entry header offset |
| 94 | 2 | u16 | entry header size |
| 96 | 4 | u32 | entry count |
This header provides the number and location of entries in the WAD archive. Entry headers start at the entry header offset and are spaced by the entry header size. (In practice, they immediately follow the directory header and are contiguous.)
Following the WAD header is the directory entry.
| Pos | Size | Format | Description |
|---|---|---|---|
| 0 | 256 | ECDSA signature | |
| 256 | 8 | XXH64 checksum | |
| 264 | 4 | u32 | entry count |
This header provides the number of entries in the WAD archive. Entry headers immediately follow the directory header and are contiguous.
Entry header format is somewhat compatible with all WAD versions: new fields are added to the end of the structure.
WAD version 1 ends at the data type field, followed by 3 padding bytes (for alignment). WAD versions 2 and 3 include all fields.
| Pos | Size | Format | Description |
|---|---|---|---|
| 0 | 8 | u64 | path hash |
| 8 | 4 | u32 | data offset in the WAD archive |
| 12 | 4 | u32 | compressed size |
| 16 | 4 | u32 | uncompressed size |
| 20:0 | 0:4 | u4 | data type |
| 20:4 | 0:4 | u4 | count of subchunks |
| 21 | 1 | bool | set for duplicate entries |
| 22 | 2 | u16 | index of first subchunk |
| 24 | 8 | entry checksum |
For version 3.4 onwards, the duplicate field is instead used as high byte for the first subchunk index.
That means its value is multiplied by 216 and added to the index of first subchunk field.
The following data types are known:
0 -- uncompressed data1 -- gzip2 -- file redirection3 -- Zstandard4 -- Zstandard with subchunksIntroduced in 3.3.
Subchunked entries consist of multiple ZStandard compressed frames.
Subchunk headers are packed as an array inside of a dedicated entry.
The name of this dedicated entry is derived by swapping the .wad.client extension with .wad.SubChunkTOC.
This allows the client to skip decompressing unecessary parts of files (example: unused mipmaps).
| Pos | Size | Format | Description |
|---|---|---|---|
| 0 | 4 | u32 | compressed size |
| 4 | 4 | u32 | uncompressed size |
| 8 | 8 | subchunk checksum |
Paths of files in WAD archives are hashed using 64-bit XXH64 with seed 0. Since paths are not stored in the archive in clear, they have to be guessed.
Hashed paths are all in lowercase. They usually use letters, digits and
characters from ._-/. Rare occurrences also use spaces and @.
List of reversed hashes are available in Data repository.
If an entry is duplicated, it's offset points to data of first entry which is not duplicated. Pointed entry does not have duplicated flag set, only subsequent entries have it. This is a technique to lower file sizes.
Not present for entry headers before wad version 3. For version 3.0 this is first 8 bytes of sha256 hash. Starting with version 3.1 this is xxh3_64bits hash.
For file redirection entries, the data offset points to an u32 specifying the
length of the file redirection that follows it.
The file redirection is a string path. It tells the game to load the file redirection file path instead of the one the xxHash specifies.