Vromfs

What is Vromfs?

Vromfs is a type of virtual file system used by Dagor games.

Files and directories are compressed into a single file with the extension .vromfs.bin. This file can be both compressed and cryptographically signed during creation.

Files are created and managed using vromfsPacker-dev.exe, which can also unpack them. To use it, run the command:

vromfsPacker-dev.exe some_config.blk

The configuration file in .blk format, contains rules for compression, specifying what to compress, the source and destination paths of directories, compression settings, signing, etc.

You can open a .vromfs.bin file to inspect which directories and files are compressed within each vrom file and identify their source paths. It is also possible to decompress a vrom file manually.

Using vroms protects data from modification and significantly reduces load times.

Important Tips and Hints

• Potential Issues: Using the flag has drawbacks. For example, the disappearance of a file might go unnoticed because it would still be found in the vrom.

• daNetGame Approach: daNetGame-based games use a different concept. All add-ons and vroms are mounted to the game via a list in settings.blk, which also provides the source of the vrom. The flag debug{useAddonVromSrc:b=yes} tells the game to ignore vroms and instead mount the provided directories.

• Advantages of Vroms: Vroms are small and can hold vital information, such as scripts and game data, which allows updates or patches without a full patch (particularly important for consoles or phones where quick updates are not feasible). Consequently, vroms are updated in all games. In WarThunder, this is done via a special service that also synchronizes vroms between dedicated servers and clients. In daNetGame-based games, the game downloads these files at startup (only on consoles). Future updates may include downloading vroms before joining queues or in other scenarios.