March 2018 Update - Diplomacy
Hey all, in this update we'll be taking a quick tour of the design for the new diplomacy system.
In last month's post I talked a lot about high-level design goals, but another important consideration is how things actually play out from the player's perspective, especially with an abstract system like diplomacy. What is the actual thing that you're doing? What is the player trying to achieve? You know, what's the point?
This being a game about Barbarians in the Dark Ages diplomacy in AtG is pretty blunt and straightforward. Your goal isn't building trade networks, spreading your religion, or anything particularly nuanced - the focus here is on war and relationships which lead to it (or not). Having someone declare war on you is the punishment for unsuccessfully navigating the turbulent waters of international politics, and remaining at peace (and thus able to follow through on whatever agenda you're pursuing) is the reward for success.
Success won't come easy though, as some leaders are naturally cranky while others might be in the midst of a feud and expect you to take sides. Who you support and who you snub is a big deal in AtG, because make someone mad enough and you can be pretty sure that they'll show up on your doorstep with lots of unhappy friends.
Furthermore, once you've made an investment in a relationship there should be a tangible reward for having done so. This is often where diplomacy systems in other strategy games fall short, as the fickle whims of the AI RNG can easily spoil a lot of hard work. If the decisions you make don't effectively keep you out of war then everything falls apart pretty quickly, so we also need to make sure relationships in AtG are fairly reliable.
With all of this in mind here are the elements we've included, and the very specific roles we have in mind for them.
Leverage is simply the sum of the player's Relationship Level, Influence, and Reputation (see below) that is or would be spent in a single transaction in order to get an AI Leader to do something, such as declare war on another Leader. After a transaction is finalized, the Influence and Reputation used in achieving it is spent and forever gone, while the Relationship Level remains unchanged.
Relationship Level (RL)
The most basic metric into diplomatic relationship is your Relationship Level. RL determines how favorably or unfavorably disposed an AI Leader is towards the player. It shapes that Leader's behavior, e.g. willingness to make Demands or go to war. In terms of specifics, it is a fundamental component of how a Leader decides which "Approach" to use (see below) and RL is a factor in determining Leverage when negotiating a transaction. The RL scale ranges from -4 to +4 and normally starts at 0, but can be modified based on a Leader's Personality Traits (e.g. -2 RL if 'Belligerent'). Having 9 total levels provides both enough room to do interesting things but also not so many that keeping track of where you are on the scale becomes a chore - each level matters while still providing enough wiggle room to move up and down with varying granularity based on the situation (refusing a request for aid is bad, but declaring war is really bad).
Influence is, in essence, diplomatic currency with a Leader. It can be spent alongside RL and Reputation in order to increase your Leverage with a Leader when negotiating a transaction of some kind (e.g. asking the Leader to Denounce someone else, or publicly Declare Friendship). Inf is usually earned and lost alongside RL - doing a small favor for a Leader might increase both your RL and Inf by 1. This gives players the option of achieving some kind of bigger diplomatic option once, after which the Inf is spent. The player's options will be more limited after that, but they will still remain friends with the other Leader. The Player can proactively earn Inf by Offering a Gift or Holding a Feast in a Leader's honor (see below).
The fourth and final Diplomatic metric is Reputation, which is similar to Inf except for being a global currency that can be spent with any Leader (in addition to or instead of Inf). Rep is fairly hard to earn, and usually comes from facing down some kind of difficult situation (e.g. agreeing to help a Leader in need, or refusing a demand from Attila knowing he will go to war as a result). The effect and usage of Rep can differ based on the Leader and their Personality Traits (e.g. an 'Isolationist' Leader might ignore Rep entirely, while it might have double the effect on a 'Gullible' Leader).
The game contains a list of core actions that can be taken by either the human player or AI Leaders. The full list is as follows:
- Offer Gift (Wealth)
- Hold Feast (Food Gift)
- Request Aid (Food)
- Request Alliance
- Request Denouncement
- Request War
- Demand Tribute
- Demand Denouncement
- Declare War
Each Action has different requirements, costs, and effects associated with them that I won't bother to list out in full here, as it's a lot of numbers and I mainly want to focus on mechanics. For the most part Actions can usually only be performed once, so it won't be possible to butter someone up by holding feasts in their honor every few months or anything like that (though you can of course declare war more than once).
The effects of an Action are pretty much fully predictable. If Attila Demands Tribute of you, then you know that by accepting your RL will increase and he'll leave you alone. Refuse and it will drop, making you a target but also earning Rep that you can spend with other Leaders (should you survive long enough to take advantage of it!).
AI Leader Behavior
The final piece of the puzzle is how the AI leaders actually decide what to do on their end, and this is ultimately defined by their "Approach" towards each other Leader. Different leaders will have preferences for different Approaches, but the effects of the approaches themselves is fairly consistent.
The early game doesn't involve much diplo - players are simply exploring the map and run into each other. Not much happens on the diplomatic front during the first 48 turns - from this point on things start to get interesting though.
Early interaction mainly takes 3 forms:
- Bullies trying to put other Leaders in their place, primarily through making Demands (and then following up with war should they refuse to give in).
- Friendly Leaders (especially those with the 'Social' or 'Needy' Personality Traits) making requests.
- Leaders who dislike each other trying to undercut their rival with the Player's help.
These behaviors are defined by which one of several Approaches an AI Leader has chosen to adopt for each relationship:
- Bully - Active
- Bully - Inactive
Similar to the Diplomatic Actions above there are a lot of numbers associated with each of these that I won't bother with here. Which Approach an AI Leader chooses for a relationship very much depends on the RL, with Personality Traits and to a lesser extent randomness also being factors.
A Leader's Approach will often change based on game events, such as being denounced or given a gift. Valid Approaches, along with the percent chance of transitioning between them after different triggers (e.g. receiving a demand) are defined by the Leader's Traits. These Approaches don't predefine what a Leader does, but do define the pool of options and the likelihood of each being chosen after how long (e.g. if demand refused 50% chance of denouncing 3-6 turns later).
I thought a bit about whether or not a Leader's Approach should be visible to the Player, and after going back and forth for a bit I decided to go ahead and make it public and announce all changes via notification. Transparency is very important in a system like this, and having something which fundamentally drives an AI Leader's behavior hidden under the hood felt like a mistake, especially given how straightforward the rest of the system is (RL, Leverage, etc.).
Making Approach visible means announcing changes via a notification is necessary, as the last thing we want to do is encourage players to check the diplo screen with every Leader every turn! This was a flaw in some early Civ diplo systems that I very much don't intent to repeat in AtG. On the plus side, this will help highlight the system for newer players, as although nothing is changing mechanically it reminds you that diplomacy is, you know, a thing, and if other Leaders are starting to get upset at you that you need to get up off your butt and be proactive.
As one last aside, I considered adopting some kind of "storyline" system where different Leaders would follow somewhat pre-structured plans for their diplomatic endeavors, but ultimately deemed it to be too much work for this game - perhaps a project for a future game!
That's it for this month's update. Given that diplomacy is the last big system to go in from here on out we'll probably be focused more on details and less on high-level design concepts.
Thanks as always for reading, and we'll be back in April!