Unity Foundational Architecture: Managing Global State

Table of Contents: Introduction Constants Singletons & Services Singleton Service Locator Introduction Every Unity developer eventually hits the exact same wall: how do I get my UI script to talk to my Game Manager without turning my codebase into a tangled web of dependencies? Managing global state is a fundamental challenge in game architecture, and the internet is full of conflicting, often dogmatic advice on how to handle it. In this article, we are going to look at some popular approaches to managing global state: Static Constants, Singletons and Service Locator. Before we start though, I encourage you to read some of my previous blog posts in this series on project scaffolding or, even more crucial to some sections in this article, the bootstrapping process . Constants Not every piece of global data needs a instance to live in, interfaces, or an initialization phase. Some data is constant and never changes at runtime (constants). These constants are usually defined with static readonly or const (at least they should be if they never change). Example: public static class MathConstants { public const float MilesToKm = 1.60934f ; } public class CharacterAnimationController : MonoBehaviour { // we must use static readonly instead of const here because we need to generate the SpeedHash from the string literal. public static readonly int SpeedHash = Animator . StringToHash ( "Speed" ); } Constants are also tied to the type they are defined in. So to keep things neat, you should only define constants where appropriate. Meaning if you have a constant for the max networked inventory slot capacity, this shouldn't be defined in a class called NetworkedConstants and instead should reside inside the class that represents the NetworkedInventory which needs this data. In fact, if this is the only class that needs this data, you can even make it private although it's perfectly fine to make it public as well if there's a need for it in other scripts as long as you are not just