Archives (BSAs)

Certain Bethesda files like textures, meshes, and similar assets are often stored in zipped up files with extensions like .bsa or b2a.

Mutagen calls these Archives and offers API to read the contents from those. Writing new Archives is not something Mutagen can currently do, but is on the list of features to eventually be added.

Reading

Archive Reader

To start reading an Archive, you must make an Archive Reader:

var reader = Archive.CreateReader(GameRelease.SkyrimSE, somePathToBSA);

File Enumeration

With an Archive Reader, you can enumerate all the files it contains:

foreach (var file in reader.Files)
{
    Console.WriteLine($"File at {file.Path}, with size {file.Size}");

    var fileBytes = file.GetBytes();
    // You can also get the file data by stream
}

Folder Lookup

Archive Readers can also look up specific folders:

if (reader.TryGetFolder("some/sub/folder", out var archiveFolder))
{
   // Found the folder inside the archive
}

Folders have similar API of looping contained files as an Archive Reader

Finding Applicable Archives

(Todo)