We have two projects underway and want to share some classes between them. The shared source must be in a single location so when a programmer on Project1 updates the code those changes are immediately seen in Project2.
The important part is that we do not want to maintain multiple copies of the same code. i think we would agree that its simply bad practise to do so.
The only option appears to be putting the code in a class library and load it as a plugin into each project. But I don't believe this works when referencing Unity types like GameObject or transform.
In C/C++ land we could put the source in a directory and include it into any solution we wanted - doesn't seem to be so easy in Unity-land. Is their a better way to share code between unity projects?
EDIT: All projects, including the shared code, are already under source control. This is not a Source Control question, its a framework issue. (And obviously I need to write better questions!)
Lets say the directory structure looks like this...
Can Unity reference code from other projects? Can Unity reference code outside of its own Assets folder? If so, how?
I had originally flagged this as a duplicate question: http://answers.unity3d.com/questions/9658/what-needs-to-go-into-source-control-to-share-a-project-unitypro, but on re-reading - it's not exactly the same, although it seems like you're trying to solve the same problem from two different directions.
This is definetely an extension of 9658. I felt it warranted splitting into two seperate parts to make it easier for the community to find specific answers.
If the problem is not source control, and you have a solution for that side of things, then symbolic links could help. Put your shared code in a sub-folder of Assets, then move the subfolder to a shared location and link it into all the projects that use it. Windows 7 symlinks are (finally!) pretty good. See "mklink /?" for details.
The link from the first comment seems to be brokenHere's the fixed one: http://answers.unity3d.com/questions/16907/what-needs-to-go-into-source-control-to-share-a-pr.html
Answer by Lucas Meijer 1
May 14, 2010 at 05:45 PM
You can share code (and assets like prefabs) effectively like this:
Use external versioning support. (I'll use subversion in this example, but most versioncontrol systems support this scenario).
Version your game at:
Version your shared code at:
Now, in the checkout of the game, create a folder called "SharedCode", and set its
svn:external property to the svn url of your shared code svn location.
This way you can easily share your "common" code amongst different games. If your needs get a bit more complex, you can also branch your sharedcode project to something like:
if you want to "freeze" the version of the sharedcode that the monkeydonkey game uses.
(for instance, when a game gets close to shipping, but you have another game in full production, it's likely that you don't want to the sharedcode updates to be picked up by your almost shipping game, due to risks of accidentally introducing a bug).
I find this to work pretty well myself, as you can easily commit changes to both your game, and the engine code.
Had not thought about sharing assets & prefabs too. Thats very cool, thanks Lucas.
This may be a dumb question, I'd already thought about doing this as specified, but I was concerned about the metadata files. Is it possible for one project to change them and then cause problems in another project that's using the same library?
so, that's basically saying "no, unity can't do it. instead, use your source control of choice, such as git's submodules, subtree or even cherry-picking"
Hi I'm a newbie. I had the exact same question, but also the exact same concern as squidbot in the above comment. Has anyone answered how meta data works when shared between projects? We believe it breaks our project links. Thanks.
Dear @wrxmarcus and squidbot: I'm not following your concerns. You have to keep the ".meta" file always together with its "parent". That's all, and nothing breaks down. If you lose the meta, you lose its information, but it will be recreated and only what has been lost from the meta would be "broken", and the meta recreated with a warning. That's still far from breaking the whole project.
Answer by Michael La Voie
May 07, 2010 at 11:22 PM
The link provided by @Cyclops may provide part of the answer. Sharing the code could be accomplished through a clever use of source control.
Your scripts (and potentially the whole project if you have pro) should be under source control already. Consider moving all shared code into a single root folder. Keep this folder out of your source control by ignoring it. Create a new repository just for this shared code.
With this model, you can develop in both projects making changes to project-specific and shared code. The only extra work comes when its time to check-in and sync your changes to the server. Instead of only doing it once, you'll do it for the project specific repository and the shared one.
When working on either project, always remember to check out the latest version of the shared code and you should have a single point for managing all that code.
You definitely should have everything under version control - this "keeping in a single location so that it's immediately updated" is a bad idea, as it can break someone's changes. To expand on Michael's answer, I use git to keep track of the project as a whole, but have a submodule specifically for code - that way I keep the binary data from the scenes separate from the text-based code which is re-usable across projects.
Hey @Ricardo, although I agree that it could lead to breaking code in another project, that risk will come with any method of sharing code between projects.
Hi Michael. Sure, but it's a lot more likely on his originally suggested approach, where he doesn't use a vcs and instead expects the directory to auto-update.
@ricardo, I am using VCS. I thought this was implied in the question but obviously not. Thanks for bringing it up! I've made appropriate edits.
Answer by eventropy
May 29, 2016 at 07:55 PM
You could also try Projeny - a free open source framework that addresses this problem for both assets and scripts (using symlinks)
Answer by LI LONG
Dec 05, 2013 at 08:03 AM
I found a really nice way to share code,perfab and any others in different unity project, yes, that is SVN indeed, see here https://help.cloudforge.com/entries/22483742-Setting-up-svn-externals we can create a new project using svn, then in the unity project, just set a folder property to svn:externals and link to our porject we created and we must use the svn as the version control system.not the asset server provided by unity
that's really a nice method
Answer by FamerJoe
Jan 05, 2014 at 08:59 PM
The solution I came up with doesn't use DLLs or SVN.
-Make a new project, and add your shared scripts etc
-Grab Belvedere, a free automatic file manager
-Add the scripts folder to Belvedere, then create a rule for each project that says any file date last modified 1 second ago, copy them to a location in your project. The result is when you modify any of those shared scripts, or add new scripts, all your projects will be automatically updated.
-Whenever you start a new project, simply add a new rule to Belvedere, and watch your shared files populate your new project.
It works quite well!
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