Pac-Man's Ghost Behavior Algorithms 194
An anonymous reader writes "This article has a very interesting description of the algorithms behind the ghosts in Pac-Man. I had no idea about most of this information, but that's probably because it's difficult to study the ghosts when I die every 30 seconds. Quoting: 'The ghosts are always in one of three possible modes: Chase, Scatter, or Frightened. The "normal" mode with the ghosts pursuing Pac-Man is Chase, and this is the one that they spend most of their time in. While in Chase mode, all of the ghosts use Pac-Man's position as a factor in selecting their target tile, though it is more significant to some ghosts than others. In Scatter mode, each ghost has a fixed target tile, each of which is located just outside a different corner of the maze. This causes the four ghosts to disperse to the corners whenever they are in this mode. Frightened mode is unique because the ghosts do not have a specific target tile while in this mode. Instead, they pseudorandomly decide which turns to make at every intersection.'"
Programming lesson (Score:5, Insightful)
Take note CS professors: writing a Pac Man ghost algorithm would be an awesome exercise.
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Writing a Pac Man MAN algorithm would be better.
Re:Programming lesson (Score:5, Interesting)
Re:Programming lesson (Score:4, Funny)
Then you'll get one kid who goes "Aww man. I totally thought this was Ms Pacman! I built it with no sense of direction whatsoever!"
Re:Programming lesson (Score:4, Funny)
Don't be sexist. Chicks hate that.
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Re:Programming lesson (Score:5, Funny)
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Shut up.
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+1 Thank you. If I had mod points, I'd mod you up.
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Re:Programming lesson (Score:4, Interesting)
It's been scientifically proven that statistically men have better 3D perceptualization than women - yes some women are better at it than men, but when you plot it all out you get the regular bell curves, and men typically have higher preforming scores.
So it's not like jokes revolving around a woman's ability to park a car, or judging how far away an object is, or any of the things that seem to be related to navigation - they do have SOME foundation to it. (if you don't believe me, Google "Women's Depth Perception")
Much in the same way that colourblindness is strictly a male thing - if a woman is colourblind, it typically means that some dominant male gene actually took control when their eyes developed, which is quite rare in women. But also in Women its rare that they sometimes get a 4th "cone" in their eye that helps identifying in colours. This is why women tend to be better at items like interior design and Fashion, so the jokes about how "Men can't dress themselves" also have a good foundation. Like before, "some men are better than women at that sort of stuff" - but statistically speaking, this is a good strong point for women.
So - now that the science is out of the way - what does this have to do with Offensive jokes? That's the thing, they are just jokes. I mean in it in a light tone and while some might take it as derogatory, there are any number of things someone could make fun of me for (as you might have pointed out, my apparent lack of tact and manners!).
It boils down to this: do I value a good joke over someone elses potential feelings? Personally, I do enjoy a good joke. I think that the enjoyment it brings to me and others outweighs the possible negative feelings that a small contingent might actually feel - after all not ALL women are offended by such jokes.
A wise man once said... well I can't remember the exact words, but it was something along the lines of "Wisdom starts with humility". If you can't laugh at yourself than thats something you should work on. Recognising your shortfalls is the first step to overcoming them.
Now - the biggest problem I have with people is when they can't seperate Discrimination, prejudice, or harassment from humour. Like when you're at an Open source conference, and you're a women, like the article you linked. Guys taking upskirt photos of women? Yeah sexual harassment. Ignoring females because they are believed to be non-technical? Yeah discrimination. A picture of a girl in a Bikini during a slide show to say "That was just to get your attention" - Thats humour! It's meant in light fun, I bet if you had enough girls around you'd find them chuckling at the idea as well.
Point is - people need to lighten up. If more people could understand the difference between humour and harassment - the world would be a much better, and funnier place.
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Top scientists think the reason decreased depth perception arose in women is because of the thousands of years men have been convincing them that something 5inches long is actually 8inches.
Re:Programming lesson (Score:4, Interesting)
It's been scientifically proven that statistically men have better 3D perceptualization than women - yes some women are better at it than men, but when you plot it all out you get the regular bell curves, and men typically have higher preforming scores.
Really now? Can you link me to a few unbiased studies the topic with statistically significant sample sizes and shows results of men having, not only higher scores, but statistically significantly higher scores? I assume, of course, that you also have available the justification for why we can trust the tests to be testing purely for 3d perceptualisation, without testing for additional unrelated factors (such as how well you can decipher difficult instructions, a common additional factor in such tests). And I also trust that these studies have properly isolated for sex, ensuring that additional factors such as training and practice in related skills or a lifetime of "you can do anything" vs. "oh, you're just a girl" have no bearing on the final results?
I'll be rather impressed if you can show me any such study. Now, I'll be the first to admit that not all people are created equal and that it is quite possible that people of different sexes and genders and races and sexual orientations have some amount of differences. However, I think you'll find that most of these studies in these topics are entirely inconclusive after you consider all of the factors surrounding them.
It's also worth noting the striking parallels to the number of 19th century studies "proving" that black people were strictly inferior to white people. Confirmation bias can prove anything, as it turns out.
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Gay, Straight, and the Reason Why: The Science of Sexual Orientation [amazon.co.uk] covers various physical and psychological differences between males and females. Pages 107 to 109 refer to the studies that may be of interest to you.
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And I also trust that these studies have properly isolated for sex, ensuring that additional factors such as training and practice in related skills or a lifetime of "you can do anything" vs. "oh, you're just a girl" have no bearing on the final results?
But that is not really necessary if you simply want to know something about the current population. If the cause of the observed difference (if any) is environment or inheritance is really a different thing.
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But that is not really necessary if you simply want to know something about the current population. If the cause of the observed difference (if any) is environment or inheritance is really a different thing.
That's where we get into some shady areas. For one, if it's an environmental difference, but only in the American population in 2008, it doesn't even come close to proving that men are better at it (although you might get away with the statement that, currently in the United States men are better at 3D perceptualisation, so long as the rest of the conditions I listed have been filled, but that's a vastly different statement). Similarly, an environmental distance, even in a worldwide study, from 1970 would
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A wise man once said... well I can't remember the exact words, but it was something along the lines of "Wisdom starts with humility". If you can't laugh at yourself than thats something you should work on.
Men making misogynistic jokes aren't laughing at themselves. They're laughing at other people. That's pretty much the opposite of humility.
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I've actually come to realize that I have what can only be described as "color dyslexia", especially with pink and purple. I can tell the shades apart - if you put something pink and something purple in front of me, I can tell you that they're different - but when you show me a pink item and ask me what color it is, half the time I'll tell you it's purple.
It's really weird.
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While there have been numerous studies showing that there is a statistically significant difference between women and men in regards 3D thinking, that statistically significant difference turns out to not be particularly meaningful when taken out of the lab and applied to real-world activities. It's the same for the studies that prove that women have a statistically significant edge over men when it comes to processing language - women have the edge in controlled experiments, but when brought into the real
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It's always nice to read a sincere compliment, regardless of the venue. Thanks :)
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Besides, to be more specific, color blindness is caused by a recessive gene on the X that isn't matched on the Y. So it's carried by women, but a woman has to inherit it from both parents to be colorblind, a man needs only inherit it from his mother, and a woman who is hybrid for it actually has better color perception that "normal", as the gene in question causes one type of cone to favor an abnormal color range. If a woman is hybrid for the gene, she gets both the normal and abnormal versions of the con
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Oh yes. If there's ONE FUCKING THING WE NEED, it's another community so afraid of offending anyone, we walk around mincing words and generally acting like complete pussies.
How is it mincing words to refrain from insulting 50% of the world's population just for a chuckle? If you don't go around gratuitously demeaning everyone you possibly can then you're being a pussy?
I work in the education field, and it's completely pathological there. You can get fired, directly or indirectly, for saying anything not politically correct. (Indirectly is a lot more common, by the by.)
I'll admit that that sucks, but you're basically saying that if we start respecting women's intelligence and individuality then we'll automatically end up there. I don't think that's an accurate appraisal of the situation. The biggest reason education is as f---ed up as it is (and believe me I know, my wife te
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I'm not saying 'Thought Police - Make An Arrest!' - I just asked the OP to re-consider their comment, and how it might affect women within the community, in light of the current issues the broader community have.
Aha! I see what you did there! ;)
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If someone says "stop being an asshole" and your conclusion is "but then I will have nothing to say", what the hell is wrong with you?
I am continually amazed with what people defend this behavior with. You don't need to be devoid of humor or steeped in forced neutrality, you don't need to stop speaking your mind or fear that you can't have an open and honest discussion. You just need to stop being a dick. (Which would probably help any arguments you're trying to make in any case.)
("You" doesn't refer to par
Mod Parent +Insightful (Score:2)
Look at the Slashdot censorship (Score:2)
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Kinda makes you feel like the mods are compensating for something, doesn't it? Maybe you hit too close to home...
Is this a joke about small penises? I hope the girls aren't offended too much.
I intended to imply that they were compensating for their guilt by attacking the messenger, but I am also aware of the sexual implications and am perfectly fine if people take it that way, too. I don't think anyone already on /. will be offended, and if you think that's what this discussion is about, you probably should go back and read the original link.
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Domestic violence is serious and the vast majority of it is man-on-woman.
That is a common myth, there is a significant percentage of women-on-men violence, and many studies and meta-studies suggest the rates may be equal.
"Martin S. Fiebert of the Department of Psychology at California State University, Long Beach, provides an annotated bibliography of over two hundred scholarly works which demonstrate that women and men often exhibit comparable levels of IPV violence.[110] In a Los Angeles Times article about male victims of domestic violence, Fiebert suggests that "...consensus
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Trust me. You can do far more damage to someone psychologically by not hitting them physically. Imagine this. You wake up and find your head shaved and/or your hair glued to the pillow. You step out of bed onto an emptied box of thumbtacks. When you get downstairs, you find out that your pet dog is hanging from the ceiling fan with its guts strewn on the floor. Your elementary school daughter's class schedule is missing from the front of the refrigerator, and the words "You're next" are written in the
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Re:Programming lesson (Score:4, Informative)
It's awful that some people have gone so far off the deep end that simple jokes cannot be told without questioning their intentions.
I don't think anyone was questioning the intentions. They were questioning the effects that such jokes have on the culture, particularly when they are so one-sidedly against women all the time. It's great that you're an equal-opportunity offender and I salute that, but the FOSS community as a whole is not. Even if the individual jokes themselves are all meant in good fun, taken together they create a boys'-club atmosphere that is not healthy to the growth of the community.
On the other hand, folks are overly sensitive about some things. No one granted anyone the 'unalienable right' to not be offended. Some shit offends me too, but I get over it.
I would re-read the link notionalTenacity posted. It isn't about safeguarding the right not to be offended, because of course no such right exists. It's about creating an environment that encourages all to participate, which is not something we have a "right" to but would be a very smart thing for the FOSS community to foster.
Have you tried getting over it and trying to have a sense of humor? Not about things like the dude sticking his hand down the chick's pants....that's messed up and he should at least have the hell beaten out of him a few good times for it. About things like "hur hur, women ain't got no direction smarts!"
You don't think the two are related? Really, would a man really try to stick his hand down a woman's pants at a conference where people didn't make repeated jokes about the entire female sex and there weren't pictures of women in bikinis in the presentations? One sexist joke is harmless, if it's the only one, but that kind of pervasive behavior creates an environment where men literally think, "these women are here to pleasure me, not to participate in tech talk", and that mindset leads directly to the odd one attempting the ol' scoop-n-grab.
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The problem you seem to have is that you can't distinguish attempted humour from actual sexism. There is a lot of difference between "haha women can't park" and "durhur men a jerks", and actual sexist behaviour. And before you start, I'm gay, so yes I do know what both are like.
I think this is something you need to work on rather than attempt to change everyone around you.
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The problem you seem to have is that you can't distinguish attempted humour from actual sexism.
Once again, no. If you'd actually read my post you would know this was not the case. I can distinguish perfectly well between a joke and a discriminatory belief, but the entire point I was making was that even though they are different, the one reinforces the other in most cases.
There is a lot of difference between "haha women can't park" and "durhur men a jerks", and actual sexist behaviour.
And apparently you believe "actual sexist behaviour" arises in a vacuum with no reinforcement from people in the environment saying sexist things. The two can't possibly be related, can they?
And before you start, I'm gay, so yes I do know what both are like.
I don't see how this makes you any sor
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So every time somebody says gays should be denied all rights, or should all be murdered, and you have a problem with it but then they claim they were just joking, how about I tell you it's something you need to work on rather than attempt to change everyone around you?
Wouldn't that come under knowing the difference between attempted humour from actual sexism? Why is it in your world, you're the only one enlightened to the difference while everyone else is completely oblivious?
As many people have stated, you're not improving society - you're just making society less tolerant in your own way, which doesn't actually fare better in the long run than allowing people to make bad jokes.
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Why is it in your world, you're the only one enlightened to the difference while everyone else is completely oblivious?
You're the ONLY one in this exchange who has accused someone of not knowing the difference. I don't consider myself enlightened and haven't acted like I am. I'm just trying to have a discussion of sexism, its effects, and how to fix it. That's all.
As many people have stated, you're not improving society - you're just making society less tolerant in your own way, which doesn't actually fare better in the long run than allowing people to make bad jokes.
I am in favor of allowing people to make bad jokes. The fact that you're posing my actions as the opposite of "allowing people to make bad jokes" when "allowing people to make bad jokes" is EXACTLY WHAT I AM ADVOCATING shows that you're not really applying log
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I've gone back and read your comments, and I have no idea how I came to the conclusion that I did.
You have my apologies.
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I have this nice movie you really should watch. It's called Equilibrium (or Cubic in some places). I really see the great thing with no humour (and culture) that they got going. I mean really, no wars!
Yeah, because the only type of humor is humor that demeans women. No other humorous statements are possible, or even conceivable!
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I personally don't really prefer those kinds of jokes, unless the situation makes the juxtaposition really humourous, but my point (that you're either failing to grasp or sarcastically ignoring) is that an censoring attitude to any kind of joke that offends you is a slipperly slope to disallow any jokes regardless of subject.
I completely grasp and am not ignoring your point. In fact, I completely agree, and I expressed my agreement with your point elsewhere in the thread. MY point, which I won't accuse you of either failing to grasp or sarcastically ignoring because it couldn't be clear from such a short post, is that what you call "an censoring attitude to any kind of joke that offends you" is not what's going on here. You can have care and caution to what kind of atmosphere you're creating without having a "censoring attit
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When is modern science going to find a cure for a woman's mouth?
After it finds a cure for thinking with your dick.
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When is modern science going to find a cure for a woman's mouth?
After it finds a cure for thinking with your dick.
We've had that for years, it's called Porn
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When is modern science going to find a cure for a woman's mouth?
After it finds a cure for thinking with your dick.
We've had that for years, it's called Porn
I keep trying it, but the problem only gets worse!
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Actually, in the original Pac-Man, the ghosts did not follow a "predetermined path," but actually made decisions based on some very simple logic. This was done dynamically throughout game-play. These rules, although very simple, fall still under "artificial intelligence,' since they form the basis of decision making, and thus affected the behaviour of each ghost.
The reason that memorizing patterns helped beat the game was because, based on the same conditions, the ghosts will make the same decisions every
Re:Programming lesson (Score:4, Informative)
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There's absolutely nothing in common between these. Core Wars are about trying to overwrite each other's code, the exercise GP proposed has programs secure about their integrity and controlling something in a model -- not that different from, say, Chess.
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Mmmm... google is my friend P-Robots [sources.ru]
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Considering there's 4 vs 1 and only 4 orthogonal directions you can go the ghosts have a clear advantage if they work together properly.
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Already similar things out there but with robots, not pacman. Here's one of the more popular Java/.NET versions:
http://robocode.sourceforge.net/ [sourceforge.net]
This wasn't the first. There are a whole stack of them for the C language.
Re:Programming lesson (Score:5, Interesting)
Take note CS professors: writing a Pac Man ghost algorithm would be an awesome exercise.
I wrote a PacMan in GWBasic when I was around 13 or so.
The Ghost algorithm was one of the more interesting problems. The chase rules were simple... at each intersection the ghost chose to move towards pac-man, with the one caveat that it wasn't allowed to simply reverse direction. There was also a smallish random chance that the ghost would go a different direction if available.
This made them mostly but not entirely predictable, and also helped break them up when multiple ghosts ended up in the same place behind pac-man. And was the only way they used the left-right 'teleporter'
It worked well enough and by fine tuning the random chance of going in a random direction I was able to get a pretty satisfactory game.
The algorithm was actually based more on my observations of lode-runner than of PacMan. (I desperately wanted to be able to write a lode-runner type game, but I was self-taught... and didnt' under stand data modelling. My pacman sprites navigated the maze by acutually looking a the pixel colors around them... white was a wall.
My next project was tetris a couple years later, in pascal, with the same sort of inspect the pixels to see if a row was complete, and to stop falling, see if rotations were allowed, etc.
I remember having the data model epipaphany when I was trying to write a variable width font word processing thing (again in basic), and I couldn't for the life of me figure out how to support 'backspace'; looking backwards at the screen and comparing the pixels with the bitmaps for the different letters was simply a mess...hmmm... instead of simply drawing the letters as I type and moving the cursor forwards what if I put the letters I typed into a string as well... ooooooooooh.
A real personal Eureka moment there.
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By coincidence, I've been working for the past 6 months on a port of Pac-Man to the Intellivision platform (CP-16010 CPU). I've based much of my game logic on the insight I gained from reading Jamey Pittman's The Pac-Man Dossier.
An even bigger coincidence is that this weekend I had started working on Ghost AI.
-dZ.
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the insight I gained from reading Jamey Pittman's The Pac-Man Dossier. [gamasutra.com]
FTFY. The article is fantastic and really deserves linkage.
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Programming lesson: early examples (Score:2)
Laurentius de Voltolina meets Pac-Man [handyvandal.com]
Pac-Man's Last Supper [handyvandal.com]
Always fascinating. (Score:3, Interesting)
I've known about this for years, but it's still quite fascinating. A 30-year-old game featured AI more sophisticated than what you'll find in most games today. Or at least AI appears more stupid and easier to foil today.
If I remember correctly Ms. Pac-Man added a randomization factor to avoid ghosts falling into set patterns.
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I remember there were special patterns which made cool things happen.
If you moved just the right way, then as you came down a corridor, you would go through one of the ghosts. It had to be some sort of "collision detection" bug or optimization. How the first person isolated it and documented it (at a quarter a game), who knows.
There were 30 of them in the book I bought. I was much better at Ms pacman than pacman (but only like level 12 or 13).
Re:Always fascinating. (Score:4, Informative)
I read somewhere If pac-man leaves tile A entering tile B on the same clock pulse as a ghost leaving tile B enters tile A, the machine will switch their positions on that pulse; they never occupy the same tile.
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That is correct. On an unrelated note, I discovered I was a nerd when I found myself reading up on Pac Man AI a few years ago.
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That is true. It is reproducible typically after a level has been playing for a while (during Cruise Elroy), when Blinky is going at the same speed as Pac-Man. It's pretty cool. It's predictable enough that there are some patterns exploiting this feature.
-dZ.
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Re:Always fascinating. (Score:5, Insightful)
A 30-year-old game featured AI more sophisticated than what you'll find in most games today.
I'm not sure "deciding whether to turn right or left at the fork in a 2D maze" can really compare to the ridiculously complex AI behavior in many games today. Team combat, terrain navigation, etc. Advance-to-cover squad-based tactical combat is hardly If PAC_MAN_INVINCIBLE == FALSE; Chase().
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Yeah, it might seem easier to foil some current game AI, but only because the gameplay allows you way more options than just "move in one of 4 directions." If Pac-Man had a gun and could drop proximity mines, the ghosts would seem a lot less intelligent.
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As long as you don't cross the streams.
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Because most games humans play can be mastered by computers.
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But there are behavior trees handling a huge number of potential situations, as well as a lot of good games doing things like genetic algorithms to try to find new behaviors. There's a lot, lot more going on there than pacman's 3 state AI.
Re:Always fascinating. (Score:4, Insightful)
>Well, the behavior is complex in today's games, but the algorithms are not.
Study up on the path-finding, grouping, and line-of-sight algorithms in "today's games", before you lodge this kind of insult at their developers please.
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>> We don't use path-finding algorithms to move around objects. We use spatial memory and common sense, two things game AI lacks.
Are you aware that modern games attempt to mimic precisely this? The behavioural systems are much more complex than they were back in the early days of Pac-Man--not necessarily because the programmers didn't know how to do it, but because the systems did not offer enough computational resources to accomplish it.
-dZ.
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That's hardly a fair criticism. It's if-then-else all the way down, no matter how complex you make it...
Furthermore, it's not the complexity, but the simplicity of the pac-man monster rules that is impressive, specifically just how challenging and fun and unpredictable a game could be with basically four simple rules and a maze.
Re:Always fascinating. (Score:5, Insightful)
A 30-year-old game featured AI more sophisticated than what you'll find in most games today.
In defense of games today, things where a whole lot easier when you were on a strictly 2D, non-altering, fully 100% visible plane, and where an AI that knows your exact position regardless of things like noise and line of sight wasn't considered unfair, and where the only abilities an AI had to worry about were "Move My XY coordinates to = Player XY Coordinates" -
Well I think you're getting the picture...
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AI today is significantly more complex and sophisticated. It is playing much more complex games against you. I can assure you that this is almost a purely 'oh the good old days' sort of thinking.
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Yeah, but A* is just for path finding and:
compared to pac-man AI, A* is complex.
compared to A*, modern AI is complex.
So in case that was unclear:
Modern AI is vastly more complex than A* is more complex than pac-man.
Modern AI is a complex beast built on top of fundamental algorithms like A*.
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My point was more that Modern AI has existed somewhat longer than Pac Man.
Only if you redefine "Modern" and my preprocessor threw a flag when you tried. In terms of the total time that computer software has existed, Pac-Man is an antique, a relic.
Re:Always fascinating. (Score:5, Insightful)
More sophisticated?
They are constrainted by the paths and when they have to make a choice they pick the one that gives the shortest straight line distance to their destination.
In other words they are retarded, which is good because there are four of them and they'd box the player in in about 10 seconds if they weren't.
Re:Always fascinating. (Score:5, Insightful)
In other words they are retarded, which is good because there are four of them and they'd box the player in in about 10 seconds if they weren't.
Yes. There's this persistent myth that smart game AI is hard to build. It's not. A really smart, impossible-to-beat game AI is easy to build (for most types of games). What's hard to build is a sort-of-smart-but-often-fallible AI that's just competent enough that it makes you feel like you're accomplishing something worthwhile when you finally beat it. For extra bonus hardness points you can try building an AI that makes the same kind of sub-optimal choices that a human would make so that it feels "alive". That's hard to do.
Game AIs have all kinds of advantages that make it easy (again, for most types of games) to build them to be unbeatable. They have always have instant reaction time, they can consider a large number of disparate data streams simultaneously, they always have perfect knowledge of their environment, they can have vast libraries of pre-computed decision trees, and their accuracy in moving, aiming, etc is limited only by the precision of floating-point data types. (An aside: the reason why real-world robotics is so hard is largely because real-world robots have really terrible knowledge of their environment, unlike game AIs.) The trick to writing a top-quality game AI is to figure out how to degrade and handicap all of those advantages in ways that leave them beatable while not leaving them looking stupid.
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"AI appears more stupid and easier to foil today" doesn't have anything to do with minimalism, and all to do with the non-stupidity of the AI.
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The thing is though, is that it isn't complex, it is actually quite simple. The beauty of the algorithm is that it produced complex and interesting behavior using minimal resources, that behavior however is absolutely predictable and exploitable to top-level players. There is a charm to the lack of randomness though, and even the modern Champion Editions of Pac-Man, use very similar chase algorithms to the originals, and thus share the deterministic nature of the originals.
I can't read the actual article si
NAM-CAP (Score:2)
Back in those days, we didn't have fancy graphic systems like CGA so I had to make do with VT100 and NCURSES. My ghosts were reverse video double quotes which looked good enough. Unfortunately, the 9600 baud transfer rate only allowed 2 ghosts to be playable. With that in mind, I put together a really simple chase algorithm:
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When you can beat bastard mode tetris, get back to me...
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What this reminds me of more than anything is the AI in Halo. You have a number of enemy types with comparatively simple behaviour rules, and if the game featured any one of them alone it'd be very dull indeed, like a game of Pacman where all the ghosts behave like Blinky. But the enemies are always presented in mixed groups - an Elite, several grunts, a couple of Jackals - and there's great synergy in the combination. If you can land a plasma shot on the Elite then you can take him down quickly and the gro
Crush roller (Score:3)
The most interesting behavior that i recall in those arcades was crush roller's. Only 2 "ghosts" but damn clever.
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The most interesting behavior that i recall in those arcades was crush roller's. Only 2 "ghosts" but damn clever.
I agree. Those fish were way smarter than the PacMan ghosts.
Chase, scatter, frightened .... (Score:2)
Save the best for last... (Score:3)
One final special case to be aware of are the four intersections that were colored yellow on the simplified maze diagram. These specific intersections have an extra restriction — ghosts can not choose to turn upwards from these tiles. If entering them from the right or left side they will always proceed out the opposite side (excepting a forced direction-reversal). Note that this restriction does not apply to Frightened mode, and Frightened ghosts may turn upwards here if that decision occurs randomly. A ghost entering these tiles from the top can also reverse direction back out the top if a mode switch occurs as they are entering the tile, the restriction is only applied during “regular” decision-making. If Pac-Man is being pursued closely by ghosts, he can gain some ground on them by making an upwards turn in one of these intersections, since they will be forced to take a longer route around.
It appears their web server (Score:5, Funny)
Breaking news!!!! (Score:5, Informative)
Yawn... This stuff that already been posted on the Pacman Dossier [comcast.net] for years. Not really "news for nerds".
Now, what would really be "news for nerds" is the analysis of the ghosts' behavior in Google Pacman [google.com], which is very similar, but subtly different.
Of course, since Google Pacman's source is available, this can theoretically be deduced straight from the source, but it's more fun to figure it out by trial and error. Great timekiller. There are definitely notable differences -- like certain directions the ghosts will never turn to if they enter the intersection from one direction, but will if they enter the same intersection from the opposite direction.
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I think his explanation of the the targeting decision of Inky was more accessible than Jamey Pittman's. I love The Pac-Man Dossier, and it has proven indispensable in writing my own Pac-Man port for the Intellivision (my current project). However there are some parts, like the doubling of Inky's target direction-vector based on Blinky's position, that were either under-defined, or not very clearly explained.
I've re-read that section of the Dossier multiple times to make sure I understood it completely, bu
Interesting but from my memory (Score:4, Interesting)
Re:Interesting but from my memory (Score:5, Informative)
Following exact patterns work because that generates the same exact pseudo-random number pool that the ghosts use to pick directions.
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Pac Men's heath magazine (Score:2)
If you don't want to be this http://www.nextnature.net/2008/01/pacmans-skull/ [nextnature.net] quit eating this http://truckbearingkibble.com/comic/2008/06/17/pellets-of-langerhans/ [truckbearingkibble.com]
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Well, if you're counting, then there's also "Caged" mode and "Cage Exiting" mode, and there's also "Invisible" (AKA "Just Been Eaten By Pac-Man") mode.
Presumably the "three modes" mentioned by the article refer to those that affect the state of game-play.
-dZ.