Game of Design

guyal brings up a good point in the comments.  Humans seem much more likely to ascribe connections to things on a macro level then a micro level.  In my generated story research, it’s actually proven critical.  Without this trick, this logical leap of the brain, procedural content because much harder to tie together, because the AI has to determine intent on it’s own and then communicate it to the player as well.  It’s easier if people just make intent up themselves, guided by common cultural clues.  Try laying a few randomly chosen game events next to each other and to see the connections and stories people will create.  In an interesting twist, I recall even the chapters of Don Quixote were designed to be read in any order and form an interesting plot, as was the style at the time.

I can’t find an online reference so correct me if I’m wrong.  But my search did turn up these thoughts on some of the rules of story and how to apply them to procedural storytelling.  I get so excited about this stuff.  I’ve researched and used some of these rules, but this covers a broader level of detail then seems necessary in most games, filling in too many details you could say.  But the key here is that there are rules behind stories, and rules are things we can program.  We just could use more precise rules then Mr. Simakov presents here.

The Queen of Interactive Fiction Emily Short posted some great writing tips over on her blogs.  I find IF construction fascinating, and their insights on the genre unique (as seen in Emily’s review of Portal).  Inform 7 is a great training tool if you’re an aspiring game writer, at least as a start.  The games are easy to explore too, and quite exciting and groundbreaking, a must if you haven’t tried them recently and you’ve got a few free hours.

This interview with Valve’s Doug Lombardi highlights Left 4 Dead’s AI Director, which I hadn’t heard of. Dynamic spawning is the first step towards the procedural storytelling I’ve been working on for the last couple of years. Finally some of this stuff is getting published.

Yes, dynamic procedural storytelling might ultimately never work. But, if you’ve played a pen and paper RPG you know it probably can. I’ve run these ideas through enough projects and models to feel it’s one of the next big story game revolutions, and these kinds of interviews get me all excited.

I know, I should write about it. Give me some time.

I’m in a defining mood this year, apparently.

For a long time I’ve thought there were two kinds of games, and they were approached in construction two completely different ways. Mechanics games are the mechanics driven, repeatable, shorter games, like Poker and Tetris, that derive their design from some new concepts. They are easy to spot - their PR tends to focus on these exciting new interactions. Story games are driven by their flavor. They are experience based, have a narrative arc and an ending, tend to steal their mechanics from mechanics games and polish them up. Their PR tends to focus on their characters and setting. Pretty much every big game you’ve ever heard of - Grand Theft Auto, Halo, World of Warcraft, Axis and Allies - is a story game. For a long time, I’ve thought this distinction was useful for the same reason that the PR is different - it helps you identify where you have to focus and what you have to succeed with.

But as time has gone on, this distinction has become less and less, well distinctive. It seems like the biggest distinguishing factor is no longer story or gameplay, it’s money. If your budget is over $500,000, you’re probably a story game. Portal by all rights should have been a mechanics game. It wasn’t. The prequel Narbacular Drop was. Portal was the polished up, story driven version, and it was awesome. We all loves us some story games. But we in the video game industry have lost something that still drives the majority of the market today. People love their simplicity, their mechanics exploration, and their replayability as well. Puzzle Quest, Bejeweled, and Solitaire are popular for a reason too. In a sense, story games are trying to transcend the medium, but in the process we can lose sight of where we started.

But we’re getting better. The key decision point I watch is when that “The End” screen disappears and we’re back at the main menu. If we’ve done our jobs well, story and mechanics together, players will pick “New Game” again every time. The ritual that has defined games for thousands of years.

Update: This blog reminded me of Soren’s Smart vs. Adversarial AI, and how it ties back into these concepts.  I’m thinking his Smart/Fun is directly tied to story games and Adversarial/Good is tied to mechanics games.  This model shifts most multiplayer games into the mechanics genres, which I think is all right.  Look at multiplayer game advertising.

(If you missed it) - a survey of the Top 10 most popular emotions while playing games. Fantastic work Chris. I had a lot of trouble understanding Bliss. I thought I got it, but realized later that I was really thinking of Contentment. I wonder where I experience Bliss over Contentment, if at all?

I can tell you I didn’t experience many of these emotions playing Devil May Cry 4 over the weekend. I got a whole different suite - Frustration, Anger, Bemusement, Boredom, and Sadness. Apparently not for me. Is there a survey of most common negative emotions somewhere as well?

Warning! AI Engineering Content Ahead!

I’ve been distracted all week, but I’ve been thinking about this long enough. Chris gave, in my opinion, the best talk at GDC 2008 and I’m a bit ashamed that I haven’t seen more serious consideration from the AI community about his hypothesis (the exception being here, thanks Dave!). There’s a summary of the talk here. I think he made 3 main points:

1. There are different categories of problems, which I’ve talked about before.
2. AI should be the most useful tool we have to make games. (I actually don’t agree with this. Games are primarily competitions, and many of the games we love best have no AI at all. However, that said, I do think AI is the most useful tool we have to interact with the player. AI, however, along with user interface and mechanics, is the communication between the designer and the player, and AI has the capacity to be the most detailed and most contextual.)
3. Identifying the building blocks of AI will allow us to create artistic AIs.

This third point is the most controversial, but the most insightful and the most ambitious. Can we find a basic set of building blocks for AI? Nobody seems to know. Obviously, it’s a hard problem, because it hasn’t been solved yet. And maybe that’s because it’s just not true. But I think it’s still worth examining critically. Let’s assume it’s true, that there is such a basic set. What would such a set look like? It should model “data” in a “code” system. Given my experience, it seems logically that decision-making (picking your prioritizes at any given point in time) will be our”code”. So what could be our “data”? It would have to be adaptable to the situation, reflect the personality of the character, and allow the designer to construct a set of interactions from it. Like:

• Stats. A questioner brought this up and it was a strong point. Most RPGs use stats to drive the game. Ultima 4 famously extrapolated it out to moral virtues.
• Game state. Stats are just basically game state, and game state is the core of most games. I’m pretty confident that if stats is the right direction, it will ultimately end up using the larger game state as well. Unfortunately, this doesn’t give us a lot of direction on the “code” way to go, and makes characters look a lot more like gameplay then AI.
• Actions or Behaviors. Concrete things the AI can do are another direction we could go in. This implies a “code” language to control them, which is usually script or a complex AI, but it might work. Actions are pretty tricky to imagine as a pure data set though, because they usually involve conditional logic, and have a close history with our friend the finite state machine.
• Goals. The current meme in AI engineering might work too. It’s a bit higher level then behaviors, but they are discrete controllable things. The concern I have is that in practice goal switching and control seems to be very primitive in modern games. This might be a sign it’s the right direction though.
• Objects. The Sims, for the most well known example. Objects that describe how they are used are already understood in the data-code model and are easily extensible. In this example though, Game State is usually used to set the priorities between objects.
• Animations and Motions. On an even smaller level, almost every character is seen through it’s motions. I have a hard time conceptualizing this data as AI, because there’s so many other things that can cause motion that don’t impart an AI. A player-controlled car for example. But if you broaden your definition of an AI, then there are pretty specific designer-created rules that specify when these motions occur, so they could be a core set. Unfortunately, it doesn’t seem like it simplifies anything.
• Others? Then we get down to the crazy list. Colors in the world? Sounds? Player Inputs? What else could be out there?

Of this list, it seems like Game State is the most obvious contender, since it’s a defining building block for many of these options. But it still opens up a lot of worms. How can we have a common game state given that most games are completely different? Is it really unique on a per-game basis? Or is there some sub-set of game state, like health for example, that is part of the basic art of AI? What would a tool for reacting to game state look like? I can imagine a lot of sliders and bars, maybe tweaking and tuning on a stage, until you get something that emergently looks right. We do this in test levels for AI already, so to speak. But that seems better for something like Objects or Behaviors and Goals model then it does for Game State.

This does make it seem, as I contemplate this problem, like there’s a set of underlying data and structures that really shouldn’t influence the art of AI construction at all. You could argue the triangle has the same problem in Modeling, relying on a host of 3D mathematically concepts and definitions like “point”. But I think that is a bit inaccurate - triangles really are the basic data structure of graphics and modeling. If we want to use that model as a guide, then we really should try and follow it.

I don’t know what’s next. It’s these kinds of logical loops that I think have caused others to back away from these ideas. But it seems like a fruitful area of investigation, and if I was doing AI middleware I’d be thinking a lot about this problem. What do you think?

I was going to start a page to compile some of the specialized Starcraft knowledge I’ve learned over the years, stuff that missed on the outdated battle.net page.  Unfortunately the wordpress.com software doesn’t seem to support linked page as well as say, google sites or a traditional wiki.  Does anyone have a recommendation on some way I could integrate this as a subpage into my blog?  Or a site that’s already doing this that I could contribute to?

So, after visiting “or” in Game Grammer last week, I’ve become more convinced “or” exists. There are lots of games that are complete enough and encompassing enough to be considered “or”s. World of Warcraft is a good example. It’s hard to argue that raiding and social play is not a fundamental part of the game, if not more fundamental then the leveling. But I’m still not clear on the value added.

In the most common cases, “or”s seem to add variation, very similarly to “with”s. The main difference is that “with”s are subtler and more optional - “or”s represent a broadening of the variation grey area next to “with”s. Many of these “or”s are not optional if you want to have the presented game experience, and they have the production and polish to show for that. But because there is limited focus in most products and they are not optional (World of Warcraft excluded), they seem to drag the overall quality of the game down. e.g. if you have both required combat and required vehicle levels in your game, both of them have to be easy and accessible enough that every potential player can complete them to continue. This is one of the reasons I think puzzle games may have struggled so much - puzzle games essentially are a sequence of “or” games strung together because the puzzles rarely build on learned skills over demanding new ones.

So what’s the lesson here? Be very careful adding “or”s to your game. If you can, find a way to tie them into the core game mechanically (”and”s) or make them optional (”with”s). If you can’t, recognize you’ve bitten the bullet and consider dumbing down at least one of your “or”s so that it’s not a barrier to entry and is easy to polish. And try again to tie it mechanically back into your main “core”, even if it’s just score or money. If you don’t try something early, you might find yourself dumbing all of your “or”s down instead of all but one.

Freerice.com is an interesting game, particularly in light of me highlighting Questionaut before. Not because Freerice is for charity (I have no confirmation whether it is real or not), but as an example of how taking a rather banal but important skill, studying vocabulary, and making it fun. A broad challenge set tailored to each player, a satisfying reward, simple presentation with direct usability, fast replayability, and a game with multiple skill dimensions (related words and good guessing skills really help!) make this game stand out again. We had quite a good time playing co-op too. What more can you ask?

Hi, my name is Exploration. People love me, but I can’t seem to find my mechanics. Can you help me?

Leave no stone unturned!