How does Unity handle folders and files in exported games?

Question

I am quite new in game development with Unity and was wondering how the "export game" function of unity works. I not yet used this function in unity, but I've read that it will generate some .exe file from your complete game. I also read that it will create a "data" folder or something like that.

My question is: What exactly is stored in this "data" folder? And how can I write logic to save my own files (e.g. files which contain save states, settings, configurations, etc.) in some file inside this directory (which is then shipped with the complete game / created in the local game directory after the user e.g. saved his game the first time? Can i e.g. save those files in a relative path (e.g. ./MyGame/data/savegames)?

And which types of files can I create? Text / Binary? Or can I even use some relational Database (some small one like HSQLDB)?

And how are things like models, sounds, animations and other assets treated? Are they all packaged within the .exe file which is my complete game? Or do i have some seperate folders with the shipped game for them?

Thank you!

Answer 1

The data folder (named the same as the exe file, but _Data on the end instead of .exe, which can be safely renamed to just Data) contains all of the dlls that actually run the game (even a blank Unity project will have them! The unity engine itself compiles to several dlls) as well as any Resources you might have (tip: stop using resources and use Asset Bundles instead).

Omitting this folder would be very bad indeed!

As for reading/writing other data from the hard disk (which is not possible on all platforms--looking at you web deployment) I would recommend using your own folder, eg. RuntimeData which could contain external audio, image, or video files as well as mutable data such as save games or screenshots. Pretty much anything you'd be ok with your users modifying without seriously breaking stuff (modding is "in" these days).

As for the types of file: well, that's up to you, really! Creating text files (of any extension: xml, html, dat, qqq...) is very easy. Images tend to be done through a 3rd party script (do you really want to write your own JPG converter? Video, same thing). You can also create binary files following a format of your own choosing. The only difficulty is writing the serializer and deserializer for the data, which would scale in difficulty as the complexity of the data scales.

You have full file system access* so you can realistically read or write anywhere. This is C# we're talking about. But with great power comes great responsibility.

*Note: Mobile devices heavily frown on that sort of thing and will deny access to folders outside the one explicitly given to that application.