I like it when sites talk to each other, and I just read a piece over at redkingsdream.com by Fraser Allison that’s made me want to spew some words on a bit of the subject. In The Game Narrative Triangle, Allison talks about the three aspects that actually make up a modern game. Emergent gameplay and Scripted gameplay (called Embedded in the original article but scripted works as a better term for me) are well documented, but Allison calls on a third aspect – Procedural.
It’s basically good, independant AI, summarised in the original text with an example from GTA:
“…pedestrians walking beside roads, garbage trucks cruising the streets early in the morning, police officers patrolling, cars stopping at traffic lights and negotiating corners – civilians fleeing your gunshots in panic, police officers chasing your car at high speeds, gangsters pulling guns as you approach and cars smashing into other cars in panic as the traffic flow is churned into chaos. All of these things are controlled by the computer. In one sense, it is all embedded behaviour, as the rules and AI that govern when and how each action will occur are coded in advance by the game’s designers; however, when the moment-to-moment outcomes of that behaviour could not be predicted by the creators, they are emergent narrative elements, effectively created by the computer.”
Which makes sense, and when you think about it, it’s obvious – but I for one have never really thought about it, nor does it get talked about enough because when it works it can, like in GTA’s case, really make a game. In the comments I recalled an example of it standing out brilliantly. In Liberty City a driver pulled up to a curb to hire a hooker, but in the car with him was a passenger. The hooker tried to get into the car but to do so had to pull the passenger out, who in turn saw this as an act of aggression so started a fight. The hooker lost the fight and an ambulance turned up. Then I stole the ambulance which triggered a police chase. It’s a beautiful example of something that didn’t need to happen, or anyone had planned to happen, but did – and it not only directly affected my actions, it enriched the experience.
Unfortunately I don’t think Allisons article drills into this enough, because it really is fascinating stuff. And when I think about the games that I love the most, they all focus around this idea of a framework of rules that an AI follows, rather than heavily scripted sequences or purely emergent narrative (as in Multiplayer games or games without an overarching narrative/goal such as Mount and Blade). Call of Pripyat is the strongest example; you’re dropped into The Zone and given an objective; then it’s up to you to achieve it but there are these omni-present eco-systems which push and pull you in different directions.
Cynically you could put this down to just being a diceroll of events that could occur within the gameworld – procedural ‘gameplay’ really isn’t more than a random event happening to the player – a person walking down a sidewalk is as much a random event as a mutated dog appearing, especially when you consider the murdering of the person could lead to a high speed police chase; but that really is boiling it down into harsh negativity – and after all, the enjoyment doesn’t stem from these events happening in the singular, it’s from when they clash together or spin the player off their premeditated path. So, to clarify, I’m not talking about Torchlight here which has ways to procedurally generate levels and monsters, but I am talking about being attacked by an Imp in the wilderness of Oblivion.
I suppose what it comes down to is two tiered. Firstly, the question “what happens when you take the player out of the equation?”. If the world carries on seamlessly then we are in the realm of procedural game mechanics. So, like in the STALKER example, take the player out and factions will carry on warring, mutated horrors will keep killing people, etc. The player is out of the world, but the world still works. Secondly, the question “what happens if you put the player back in?”. If, from the world carrying on, the player is going to be affected when put back in by what happened in his absence, then we are in the realm of good procedural game mechanics. So in Gal Civ, two nations have declared a peace treaty during the hiatus which has allowed them to grow, then the player turns up and is seen as a threat to their alliance, so they attack.
More games should be doing this sort of thing, really. Sure “take cover behind this explosive barrel” is giving the player AI to play with, but it would be far more interesting if that intelligence was more intricate, if it were it’s own person with it’s own tiny narrative that affected it’s behaviour. Do I sound like Peter Molyneux? Sorry. Anyway, hopefully I’m not just reciting what has been said a million times before – I don’t recall reading it anywhere anyway. Let us know your thoughts below, especially with any great examples.