I’m currently working on this ability system in Unity, and I’ve run into a real headache with cyclic dependencies in a dynamic stat system. It’s pretty good at calculating base values for stats and keeping track of buffs/debuffs, but when I try to make things dynamic, everything gets wild.
For example, I’ve set it up so that the character’s Health stat is calculated based on their Strength: it’s like half of Strength plus some base value. So if Strength changes, Health is supposed to update, too. That makes sense, right? But then I decided to add an item that boosts Strength based on Health. Suddenly, Strength is also dependent on Health, and I’ve created a cycle: Health updates, so Strength updates, and then Health updates again. It’s like a whirlwind that never stops!
I’ve been thinking about this a lot and came up with a possible solution: using a hash set (or some other structure) to keep track of which stats are currently being updated. Before updating a stat, it checks if it’s already in the set. If it is, it just throws in the towel on that update to avoid looping infinitely. Sounds reasonable, but I’m worried I might be missing something crucial in the design of this stat system.
Has anyone else dealt with similar issues? Maybe you found a better way to handle this kind of dependency? I know in game design, avoiding mechanics that could lead to these cycles is an option, but my goal is to create a rich and dynamic system that allows for more complex interactions between stats, so I really want to nail this down.
I mean, I’ve looked around for resources on implementing dynamic stat systems but keep hitting dead ends, especially when it comes to preventing stack overflows from these loops. If you’ve tackled this problem or have any insights into better ways to structure it, I’d love to hear how you approached it. Any advice or thoughts would be super helpful!
Your approach using a hash set to prevent infinite cyclic updates is sensible, as it effectively tracks already-updated stats within a single update operation, preventing stack overflows. However, relying primarily on runtime checking alone can hide design issues, potentially leading to unintended behavior or diminishing responsiveness in complex stat networks. A more robust solution is to restructure the stat dependencies into a directed acyclic graph (DAG). By clearly modeling your stats as nodes and their dependencies as edges, you can explicitly detect cycles at design or initialization stages, catching problematic interactions before gameplay even starts. This structural design ensures consistency and makes maintenance and debugging far easier in the long run.
If you really need bidirectional dependencies between Health and Strength, consider introducing intermediate derived or proxy stats. For example, rather than directly calculating Strength from Health and vice versa, introduce a separate stat (like VitalityBonus) that affects Strength, which itself is derived from Health changes indirectly and does not back-propagate immediately. Snapshots, delayed updates, or a once-per-frame recalculation pass can also help break recursive loops and stabilize values. Ultimately, clearly documented stat relationships, combined with structured dependency validation and controlled update cycles (e.g., event-driven or queued recalculation), will allow for the rich complexity you’re aiming for without spiraling into chaos.
Dealing with cyclic dependencies in a dynamic stat system can be a real puzzle, right? It sounds like you’re on the right track, but it can get tricky when you start to create interdependencies like that.
Using a hash set to track which stats are being updated is a solid idea! This way, you can avoid infinite loops by checking if you’re already in the process of updating a stat. If it is, you can skip the update, which should help keep things from spiraling out of control.
Another approach to consider is using a “dirty” flag system. When a stat is updated, you can mark it and then only do a full refresh of dependent stats at the end of your game loop or at specific intervals. This way, you can collect all changes and process them in one go, helping to prevent those back-and-forth updates. You can also decide which stats need to be recalculated and which don’t, based on the changes made.
If you feel like diving deeper into this, you might also explore the idea of event-driven systems. Instead of direct dependencies, you could have events trigger updates. For example, if Health changes, it sends an event that Strength listens for, allowing it to update only when necessary, not in immediate response. This can help decouple the direct links between the stats.
Lastly, it’s always a good idea to keep an eye on your system design. Sometimes simplifying your interactions or establishing a clear hierarchy of dependencies can make a big difference. Instead of all stats being able to affect each other, perhaps limit it to a few key stats that can influence others in a controlled way.
Good luck with your stat system! It sounds like a fun challenge to tackle!