Game wIde Global variables best practice

Hi, I’m just starting a new project which will have multiple scenes and I noticed that (in the example at least) by loading a new scene the complete hierarchy of the previous scene is destroyed.

So, my question is how do I maintain a set of game wide variables that can exist between scenes? Do I need to keep a separate (Manager) object outside of the root which contains the variables and make sure I never destroy it or is there a cleaner way?

I couldn’t find any information in the manual regarding global variables or variable scope but maybe I missed it?

Thanks :slight_smile:

Hi @Grimmy,

I think it’s a matter of preference really.

You can put variables in the global js scope by just declaring them outside of script object you create. Being a bit paranoid about breaking other js elements potentially loaded on the page, I typically stay away from it.

As you mentioned in your post, I prefer to have a manager that moves with each scene change taking all of the script that need to follow with it. That way I can keep things that need to be persistant, persistant, and everything else gets destroyed.

Ultimately it’s about your comfort level working in the global scope.

OKay thanks. Is it okay to keep my manager outside of the Root level or could that affect other things?

I believe the scene loading is additive … it just adds entities into the hierarchies. If you see the old hierarchy getting removed, that means a code to do so is called. You can simply not delete some initial scene and keep persistent scripts / data in it.

…and if i want to go back to a previous scene is there a way of loading it but excluding certain objects ie, my manager object, or would I have to manually delete the duplicate? That sounds like it could get quite messy.

Actually, what I do is have a scene that is only loaded once and let my manager and all of my persistent scripts live there. That way, I can always go back to any scene I want:

You just attach whatever scripts you want to the Scene manager entity or a child of it, and off you go.

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I generally go down the scene additive route too. Example here

Here is what I went with in the end. It seems to work.

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