Traneptora / AzurLaneDecTools

AzurLaneDecTools

Tools to handle LuaJIT files in Azur Lane 5.0. This is forked from the original repositories (here and here), which only builds on Windows.

Build

• Only supports 32-bit x86. The original code uses super unsafe pointer operations that makes a few assumptions it has no business making, like assuming size_t is an alias for unsigned int (which it isn't on x86_64).
• The compiled binaries will run on x86_64, as usual for 32b-bit x86, but if compiled natively to 64-bit x86, it will segfault upon execution. I'm way too lazy to fix this behavior so it'll have to do for now.
• If you're on Linux or another POSIX system you should be able to navigate to the base directory and run make out of the box.
• GCC you use must support -m32 and -march=i386 which usually means you need some sort of multilib GCC. On Arch Linux this is the gcc-multilib package but I'm not sure what it is on other distros.

Usage

This spits out binaries uabdec and bcdec which do two different things.

You have to obtain scripts32 from the game files on your own, which can usually be taken from an android filesystem. It's located at Android/data/com.YoStarEN.AzurLane/files/AssetBundles/scripts32. Copy it over locally, however you wish.

From a terminal, you can decrypt the scripts32 archive using uabdec:

$ uabdec ./scripts32 scripts32-dec

This creates a decrypted unity asset bundle which can be extracted with most unity bundle extractors. In particular, unityextract is a PyPI module, and you can install it with python3 -m pip unityextract. You can then dump the Lua files with:

$ mkdir -p extract/
$ unityextract --text --outdir extract/ scripts32-dec

This creates a bunch of encrypted luajit files in extract/, which we then can batch decrypt with bcdec, the other binary file from this repo.

$ mkdir -p lualj/
$ find extract/ -name '*.lua.bin' | parallel bcdec {} lualj/

This produces several compiled luajit files in lualj/. You don't need to use parallel here but it makes the process faster. find -exec is single threaded.

Now, we use luajit-decompiler to actually decompile the LuaJIT files. These LuaJIT files have a slightly mangled magic signature, but this decompiler ignores that so It Works (TM). luajit-decompiler has a batch option to operate on a directory but since it doesn't multithread, I'm going to use parallel again here.

$ mkdir -p lua-sauce/
$ find lualj/ -name '*.lua.lj' | parallel luajit-decompiler --file={} --output=lua-sauce/{/.} --catch_asserts

This should produce several lua files in lua-sauce. Behold:

$ head lua-sauce/ship_data_statistics.lua 
pg = pg or {}
pg.ship_data_statistics = {
    [100001] = {
        raid_distance = 0,
        oxy_max = 0,
        name = "Universal Bulin",
        type = 1,
        oxy_cost = 0,
        skin_id = 100000,
        english_name = "UNIV Universal Bulin",