I am a big fan of Soren Johnson's work. That being said, I keep an eye on his blog, Designer Notes. In a recent post, he listed what he felt were the "seven deadly sins" of strategy game design. Most of them were dead on for whatever reason. I thought that his first one was particularly interesting specifically because it surprised me with its presence.
He talked about how some strategy games had "too much scripting". Some of his points included:
The AI takes action depending not on its own development rate or strategic priorities but on whether the human has hit certain triggers. In many scenarios, in fact, the human cannot even lose because - when defeat approaches - the script will freeze the AI and starting pumping in free units for the player. Further, these scenarios are often built around specific "objectives" to achieve, such as destroying a specific structure or capturing a single point. This artificial environment takes decision-making away from the player. Not only is there only one path to victory, but the player’s performance along that path may not even matter. Games without interesting decisions get boring quickly.
The reason that jumped out at me was that scripting just hasn't seemed to have been a big deal to me in strategy games. I always thing of scripting in the genres of RPGs and lately a lot of FPSs as well. Not that I haven't encountered them in RTSs of the past. I used to play some of the single-player campaigns in the early RTS games like Warcraft and Starcraft. I vaguely remember the one in Empire Earth - which was one of my favorite RTS games for a long time. I have to admit that, despite my being aware that there is a campaign mode available in Civ 4, I haven't even opened it up. I don't even play a lot of the scenarios in Civ 4... just hand me a random map and let me roll.
Still, campaigns just don't do it for me. They just didn't hold me. It seemed to me to be an attempt to "personalize" the experience a la RPGs. That's not why I was playing an RTS, however. I suppose if it was done better, I may be more interested. I like the latest blending of the RPG genre with the the FPS one that seems to have been en vogue of late (e.g. Bioshock). That was a kinda cool... but for some reason, RTS + RPG doesn't quite cut it.
In the end, I suppose I agree with Soren's premise then... it is a sin to put scripted events into an RTS. It's just not what it is meant for.
For that thin slice of the industry that may visit this blog that doesn't already know about AIGameDev's new members area, you are definately going to want to jump over there and check out what's going on. Alex Chapandard's pad has been the best place for game AI info over the past year and now he is really stepping it up a notch. As of today, he has started a new members area that will not only have a lot of papers and other research material, he has been lining up a lot of live interviews and workshops with industry experts. Those are conducted online with audio, video and an interactive whiteboard. The few that he has conducted for free so far have been informative. Here's the schedule of what's going on for this fall.
Go check out what's going on over there at the members area launch page. And tell 'em Dave Mark sent you!
My buddy Paul Tozour has been epic in some of his posts lately. Here's another one, Why "AI Accelerators" Will Never Happen, that I can't believe escaped my notice for a few days. Although I wince at his use of the word "never" in the title, he does have a lot of excellent points in the article.
In the first section he talks about how the concept of "AI" is so broad that there isn't really any silver bullet that would help everyone. He actually kind of echoes a couple of columns I wrote for AIGameDev last spring on the subject. In Why Not More Simulation in Game AI?, talk about how there is that growing division between AI programmers. We just aren't doing the same thing any more... and many of us don't have a handle on what the other types do. Likewise, in Is There a Core Building Block of AI?, I cover how we really don't have a single thing we can build on... like Chris Hecker's idea of the "texture mapped triangle of AI".
I like his comment in the third section about how bad AI rarely comes from a lack of computing power. I would add the qualification that incomplete AI often comes from a lack of computing power. If we had more ticks, we can do more stuff. However, the solution isn't offloading it onto specialized hardware. All we need is either more processor or the permission to use more processor from our bosses.
Damian Isla of Bungie spoke at the recent Develop conference in the UK. He covered a lot of the history of Halo and some of the design decisions that were made in the franchise. Here's a story from Gamasutra that covers a lot of good stuff.
Specifically, there's a couple of things I want to touch on.
Halo's designers wanted the title's gameplay to explore mankind's "primal games" such as hide and seek, tag, and king of the hill, and the game's encounters were created with them in mind.
"It's evolution that taught us these primal games," said Isla. "They're the ones that are played with our reptilian brains. The idea was for the AI [to] play them back with you."
That's kind of interesting from a design standpoint. I guarantee that no one is sitting there thinking "hey, this is like King of the Hill" but they all recognize the concept on a subconcious level.
Isla pointed out that the importance of territory in Halo's encounter design is closely connected to the recharging shield mechanic that has appeared since the original game.
"Part of that recipe demands that at some point you have a safe zone," he explained. "In a sense we needed to make the AI territorial. Once you have this idea, you have to think about the problem of encounter progression as the player expands their safe zone. That itself is a pretty fun process. It gives the player a sense of progress, and is extremely plannable.
This makes a heckuva lot more sense than the "arena + safe corridor + arena..." model. What Halo did was break it up theoretically rather than physically (i.e. with walls). However, there still was the knowledge that the dudes - while still in their territory - were still going to try to take pot shots at you. You could take cover and they weren't necessarily going to come get you, but it wasn't completely safe.
Isla made special mention of AI misperception -- "the most interesting form" of good AI mistakes. If the player moves stealthily, the AI will assume the player is still sitting where the AI last knew him to be. [snip] "Each AI has an internal model of each target, and that model can be wrong," Isla summarized. "This allows the AI to be surprised by you, and this is very fun."
Amen, brother! This is something that I love seeing. I remember reading some of Damian's papers in the AI Wisdom series on exactly this concept of unknown location and search. Good stuff, man!
Still, Isla stressed, enemies shouldn't be dumb. "It's more fun to kill an enemy that's cunning, formidable, and tactical," he said, pointing out that that goal is not just an AI problem but also related to convincing animation and game fiction.
Dude... have I told you I loved you? I'm so sick of the mantra of "AI shouldn't be smart, it should be fun!" As if those two are mutually exclusive of each other.
"In Halo 2, if an AI tips over his vehicle, he walks off and forgets completely he was ever in one," said Isla. "In Halo 3, if he tips it, he remains in its vicinity fighting until there is a point where he can right it again."
According to Isla, the latter approach is "the way things should be going" -- as he puts it, "behavior should be a very thin layer on top of a world of concepts."
I would argue that behavior is more than a thin layer. Otherwise, I agree. Which really brings the concept of knowledge representation to the forefront. Not just world representation (e.g. geometry), but a general concept of how agents perceive and conceptualize things (i.e. psychology). Again, I've read some of Damian's papers on the subject. To me, he is someone who "gets it".
My friend and colleague, Paul Tozour, has put up an excellent post at the internet blog he shares with some other big names, Game/AI. In it, he covers all sorts of stuff that is "wrong" with pathfinding and offers evidence as to why nav meshes are better than waypoint graphs. There's plenty of pretty images that he has created using real-world maps... er... maps from real-world games. Definately educational and thought-provoking.
