https://github.com/Inspiaaa/UnityHFSM/tree/master

A simple yet powerful hierarchical finite state machine for the Unity game engine. It is scalable and customisable by being class-based, but also supports functions (lambdas) for rapid prototyping.

Thanks to overloading, it minimises boilerplate code while still supporting generics.

It has a special focus on the temporal aspects of state transitions, making it ideal for timing and synchronization sensitive problems.

Why use UnityHFSM?

• State machines are an amazingly easy way to write and organize game logic. (As soon as you have states, e.g. Walk, Run, Sneak, Jump, you can use a state machine)
• It's easy and straightforward to use
• It helps you tame complex behaviour (e.g. weapon handling -> cooling, ammo, reload, fire) or write AI for NPCs
• Helps you write self documenting code, that is maintainable and readable
• Reduces the boilerplate code required to write a state machine
• UnityHFSM is lightweight and efficient, making it perfect for solving small and big problems
• It is especially designed for Unity, and supports coroutines, which would otherwise be difficult to implement in a state machine
• No GC Allocations for state changes / updates / ... after setting up the state machine (-> No unwanted GC related lag spikes because of the state machine)
• The code is well documented