AI design in shooters (or stealth games)

[kingcomrade]

Since so many games nowadays are hitscan games (i.e. the enemies all use guns) enemy AI has become more important, because in a hitscan game there has to be a separate mechanic from RNG to decide whether enemies hit you are not. Right now it seems not having definite health is the current solution, and it does work. Your death depends on how much fire you are taking in general rather than how many independent hits you take before your meter hits 0.

I saw the Zero Punctuation review for splinter cell conviction and I thought the idea of enemies firing at a place where they last saw you rather than always knowing where you are was a good one. I haven't played the game so I don't know how well it was actually implemented, but it seems like a good idea.

What should the AI do? It seems like devs don't really know and just go with whatever (just like with a lot of game mechanics), most of the time. I can understand it would sometimes seem like it wouldn't make a big difference to a lazy dev.

I think AI should be predictable, but that's because I like the Doom style of shooter over the half life style where it's just a shooting gallery going down hallways (I do like cinematic feels which is why I probably like modern warfare games so much, but that's not the topic). In Doom all monsters have 2 behaviors. 1) they will always move towards you 2) they behave the same way when attacking (e.g. a zombieman will always raise his rifle and shoot a second or half a second later at the point you were at when he raised his rifle).

I think the biggest problem is just that AI is usually either clairvoyant or totally blind. I hate the first a lot more than I hate the latter. The latter is actually easily forgiveable to the point of not being a flaw, because they are video games. Metal Gear Solid, for example. It gave you the mechanics and they were predictable. Guards were blind past 5 meters, you could see where they were looking, and so on. I liked that. That made it a game, not an exercise in trying to be a realistic stealth simulation. I like games.

 

[MetalCraze]

I saw the Zero Punctuation review for splinter cell conviction and I thought the idea of enemies firing at a place where they last saw you rather than always knowing where you are was a good one. I haven't played the game so I don't know how well it was actually implemented, but it seems like a good idea.

Wow looks like consoles are finally catching up with 10 years old games from PC at least in something

That made it a game, not an exercise in trying to be a realistic stealth simulation.

No it made it a boring casual shit where you don't even need to try using your brain.

 

[Fez]

I think the gradual change as represented by the old Splinter Cell meter for stealth was more realistic and reasonable to deal with than it working like an on/off switch.

It is true that it is important to remember that what you are making is meant to be a game. Part of that is consistent and somewhat predictable rules and behaviour. It's even more important in a game than it is in a film/book/TV series story that you maintain internal consistency.

If it is a game where you are the hunter (amazing hero like Serious Sam or similar gunning through armies) then the AI just needs to provide a challenge as a target with the occasional surprise. Pretty simple AI is enough in some situations, with few 'tricks' needed. The pressure on the player coming from the overwhelming numbers, the lack of health kits or ammo limitations. Occasional set piece battles and bosses break it up enough to avoid boredom.

If you are the hunted in some form (Splinter Cell, Thief, Hitman) then the realism side of things might play a bigger part, at least in the sense of key behaviours (little 'trick's to keep it interesting) that give a good impression and act as a puzzle or check list for the player to remember while under stress (head for cover, footprints, noise levels, wear disguise whatever). Metal Gear Solid had the trails in snow playing a part at times. First time you're likely to be caught out with this, then pleased as it makes the AI look clever (it's pretty limited, but all the matters in this are the tricks) and a little more realistic. It adds an element of challenge without seeming unreasonable. It kept this consistent through the game while giving the player a chance to work around it and the developers or level designers understood the limitations of what the AI could do and what the player could do and came to a balance to make the best game of it that they could. That's good design. It doesn't always have to be the best or most realistic if you can keep it consistent and work well with it.

Inexplicably clairvoyant AI just never seems fair in most situations and usually feels buggy, unfair and arbitrary. Especially if the player has gone to extra effort to hide and then is shown no reward for this effort (thanks to the AI being able to see through obstacles or in the dark when it shouldn't, etc.). Lack of reward for effort is never good. The blind and dim AI's worst crime is usually it can get boring (although some games can fix this easily by extending sight range and accuracy with the difficulty settings or simply adding in numbers or other challanges). Clairvoyant AI at its worst can just seem game-breaking and unfair. You can design around and work with the myopic AI, but the other is always going to cripple it.

 

[Phelot]

Yeah, I would rather a dumb blind enemy then one that always knows where you are.

It would be nice though to finally have an AI that will actually flank or intelligently find alternate routes to you.

But modern FPS appear to be simply cinematic roller coasters. You kill guys sure, but the real excitement is suppose to be from all the crazy shit going on, explosions, a helicopter crashing, chatter on a radio.

A lot of games may have strived to have SOME "totally awesome" moments in their games, but games today seem to simply be entirely made of them.