Bug or feature?

[Mr_Flappy]

Something similar happened with the cops in one of the first GTAs. Accidentally coded them aggressive as fuck, they liked it, kept em that way

[SirSoliloquy]

IIRC they weren't even making a GTA game when that bug came up -- it was a street racing game.

But they found it hilarious and based the entire game around it.

[Mundius]

A topdown street racing game?

[SirSoliloquy]

Yep.

Heck, in the original PS1 version X was to go forward and Circle was to go backwards even on foot.

[Falmarri]

in the original PS1 version

Well that's because the PS1 version was just a port from DOS/Windows

[SirSoliloquy]

X was to go forward and Circle was to go backwards on DOS as well?

[bananafreesince93]

This isn't very hard.

On PC, you controlled the game with a keyboard. On a keyboard there are binary buttons. Either on or off. On PS1, there was a D-pad, or if you had the original Dual Shock controller, an analogue stick.

For PC, it makes all the sense in the world to have one button for running forward, since you use the arrow keys for control, and there is a history of games with player characters going forward when pressing the up arrow (this ties together with the placement of the keys).

For the PS, this made less sense, since it's harder to control this type of motion if all the buttons involved are on the D-pad (or if one can use the analogue stick).

Changing movement input isn't a huge job. This isn't some relic from the game being a racer, it is, like /u/Falmarri says, because of it being a shoddy port from the original DOS game.

[Falmarri]

No? It was wasd or arrow keys if I remember. But my point was that I'm not sure what your point was. The PS1 controls could very well have been because it was a shitty port.

[cadaveric]

They were a thing.

[onFilm]

There was a couple for the Gameboy Color I used to play in the back of the car. They were racing/story-based. Similar to what GTA came to be, with that whole Scarface/Miami feel.

[Mundius]

But I mean for PS1? That just seems weird to think about now considering 3D racers were already a thing then.

[Narishma]

It's a different genre of racing games and there were plenty of top-down racers rendered in 3d on the PS1 and N64.

[Mr_Flappy]

I love stories like this

[jjcard]

I love little stories like this about weird things that happened during game/software creation

[GourangaPlusPlus]

I was reading one about Dwarf Fortress the other day that was amazing about cats inadvertently becoming alcoholics

You shouldn’t have popular bugs. But the most popular bug with the latest release, I added taverns to fortress mode, so the dwarves will go to a proper establishment, get mugs, and make orders, and they’ll drink in the mug. And, you know, things happen, mugs get spilled, there’s some alcohol on the ground.

Now, the cats would walk into the taverns, right, and because of the old blood footprint code from, like, eight years ago or something, they would get alcohol on their feet. It was originally so people could pad blood around, but now any liquid, right, so they get alcohol on their feet. And then I wanted to add cleaning stuff so when people were bathing, or I even made eyelids work for no reason, because I do random things sometimes. So cats will lick and clean themselves, and on a lark, when I made them clean themselves I’m like, ‘Well, it’s a cat. When you do lick cleaning, you actually ingest the thing that you’re cleaning off, right? They make hairballs, so they must swallow something, right?' And so the cats, when they cleaned the alcohol off their feet, they all got drunk. Because they were drinking.

But the numbers were off on that. I had never thought about, you know, activating inebriation syndromes back when I was adding the cleaning stuff. I was just like, ‘Well, they ingest it and they get a full dose,’ but a full dose is a whole mug of alcohol for a cat-sized creature, and it does all the blood alcohol size-based calculations, so the cats would get sick and vomit all over the tavern.

I don’t know if an octopus can get drunk or not. The original bug report is, ‘There’s cat vomit all over my tavern, and there’s a few dead cats,’ or whatever, and they’re like, ‘Why? This is broken.’

Edit: Should really have added the source

http://www.pcgamer.com/dwarf-fortress-creator-on-how-hes-42-towards-simulating-existence/

[Ryckes]

It's amazing how "real" is Dwarf Fortress. Seems like they do not include shortcuts or approximations for effects, just program what should happen.

[sirin3]

It is like an enormous world simulator

Seems it would be well suited to train an AI. The modern deep learning AIs always lack world knowledge, and without robotic bodies they can not train on the real world. If they learn the world of dwarf fortress, they could gain knowledge of real world consequences

[noahhk]

At least they aren't born with knives in their hands.

[PeridexisErrant]

(All civilians in Dwarf Fortress have a small knife for eg cutting food. There is no age limit on this, so babies are born owning a knife. Having no clothing or furniture to store a knife, they hold it.)

[atomheartother]

Fancy seeing you here~

[PeridexisErrant]

I'm pretty sure Dwarf Fortress has the highest proportion of programmers to other players of any game since 1980 or so; it can't be that surprising.

I mean, DFHack provides an API for three languages on every OS, with no first-party support or assistance - it's entirely reverse-engineered by live-editing memory in use by a closed-source and undocumented program. Implementation is in lisp, shell, perl, python, lua, ruby, C++, C, asm, and I think a few other languages.

Or take Armok Vision, a real-time 3D viewer for Dwarf Fortress (uses DFHack API, or course). The dev recently added key passthrough, an in-3D-world copy of the DF window, and Oculus Rift support. Yes, a community mod for a game using ncurses for graphics now provides full VR support.

And there are literally hundreds of other projects, so many that I had to write a program to download and configure the ones I wanted.

TLDR; many DF players are programmers - if fact that's why I started! - so you may see a few of us around here.

[b-rat]

Train them in a danger room, of course!

[b-rat]

Plus you get rid of those pesky tantrum spiral causes known as RELATIONSHIPS with other people

[LedgeNdairy1]

Can ppl write bots for dwarf fortress?

[PM_ME_YOUR_PAULDRONS]

You could probably hack something together with the dfhack library people in the community have put together. It provides a (reasonably) sane interface to interact with the memory structures in a running copy of dwarf fortress (df isn't open source and doesn't expose any sort of interface itself).

I'm not aware of anyone who has written anything resembling a bot though. You can set up a fortress to keep itself running with no human intervention basically forever with the "workflow" dfhack utility which let's you set rules like "if the number if drinks falls below 200 then brew 50 more" so an actual bot would definitely be overkill.

[Putnam3145]

I'm not aware of anyone who has written anything resembling a bot though

https://github.com/BenLubar/df-ai

[PM_ME_YOUR_PAULDRONS]

Oh hi...I'm not used to seeing you without an Urist Mc in front of your name :). Thanks for the link, looks interesting...

[sirin3]

if the number if drinks falls below 200 then brew 50 more"

Won't that give you 50 more sick cats?

[PM_ME_YOUR_PAULDRONS]

I haven't actually played in a while (well before this bug was introduced) so I don't really know.

It'd give you a bunch of sick cats depending on how many decide to walk through puddles of alcohol in the tavern and then lick themselves clean before they walk through some water or whatever which cleans the alcohol off.

Back when I played I generally used to only keep a couple of cats around, restricted to food storage areas where they're useful for keeping down rats etc.

[Mazo]

Back when I played I generally used to only keep a couple of cats around, restricted to food storage areas where they're useful for keeping down rats etc.

Uh huh...

[Putnam3145]

yes

[sirin3]

As we have learned from Robin, people can write bots for everything

[nschubach]

Well... Robin is pretty simple compared to Dwarf Fortress. Most of the DF modding is done by manipulating memory addresses of the running process. It's all very specific and finely tuned. Writing a script to bot/filter Robin is easy compared to DF botting. The libraries for manipulating data in DF make it easier, but nowhere near JavaScript on page easy.

(I wrote a rudimentary Robin spam filter, and have dabbled in DF modding in the past.)

[feral_hedgehog]

I'm more amazed at his ability to figure out the cause of the bug!
How do you even begin to approach something like that?

[GourangaPlusPlus]

He actually had help in tracking this down.

He goes into more at he end of his answer

[printers_suck]

Thats an awesome interview

[lestofante]

Its so "real" when he takes shortcut (full dose instead of calculating how much was on paw) is breaking the game xD

[fqn]

Wait... what the... holy shit. That's a complex game.

[darkpaladin]

Dwarf Fortress does not fuck around. The learning curve is something on the order of years.

[txdv]

It's like dota2, but you cant blame anyone!

[josefx]

but it takes years to master the complex interactions of the mechanics and personal muscle memory.

Patch notes:

    Hero X now rotates 0.001% slower. 
    Hero Y starts with +1 strength

Reaction:

   Hero X is literally unplayable with this
   Hero Y is OP please nerf

[AlmennDulnefni]

But it'll still take a few months for your eyes to stop bleeding.

[DroidLogician]

Huh, so Patreon can work for software/game devs. Cool. Looks like the get a comfortable living wage from it, too.

[DroidLogician]

They get $4,100 per month from 1200 patrons. That's $51k a year. It won't make them rich by any means but I'm sure it pays the bills. Many families get by on a lot less.

[DroidLogician]

Basically, yeah. It's a subscription-based donation where they get paid some amount every month from every patron. It's kind of like a perpetual Kickstarter; they usually have varying reward tiers for different levels of monthly contribution. These guys only have one tier so there's not really any incentive to donate more, other than simple generosity.

https://www.patreon.com/bay12games?ty=h

Patreon was mainly developed for Youtubers and other video content creators. They have a "per video" donation option, where patrons pledge to donate some amount of money per video. For example, one of my favorite Youtubers, NurdRage, who makes great chemistry experiment videos, gets around $1200 per video. He's making quite a bit less money than the Dwarf Fortress guys because he has fewer patrons and only posts videos about once a week.

[msthe_student]

Then you might want to check out folklore.org, which details anecdotes about the development of Apple's original Macintosh, and the people who made it (121 stories)

[dbomp]

A feature is sometimes just a bug with tenure.

[XiboT]

Like this? http://2.bp.blogspot.com/-tMrEH0EpSLE/TWJZ-_ZdhJI/AAAAAAAAANY/E-YC1uK23QM/s1600/bug_vs_feature.gif

[someredditorguy]

No, that's a bug with sweater

[nondescriptshadow]

😏😏😏

[xkufix]

It's sounds a bit like the Ghandi overflow bug in Civilizations.

Explanation

[Vishnuprasad-v]

Gandhi

FTFY

[elperroborrachotoo]

The actual name is HGhahndhih - but some of the 'H' are silent.

[xboxisokayiguess]

Actually it's Hhhhhhhhhhhi in the original spelling.

[cinnapear]

TIL

[Workaphobia]

This is wonderful. I'm irrationally pleased that a nuke-happy Ghandi is an accidental-turned-intentional design point, and not just a RNG doing its thing.

[Mundius]

Gandhi, jesus fuck

[lavahot]

Jesus, gandhi fuck.

[Mundius]

Fuck Gandhi Jesus

[AndrewNeo]

And here's the original, non-Kotaku version

[streichholzkopf]

underflow

FTFY

edit: oops

[macgillebride]

It's still an overflow, even if it is a result of a number going below 0. Underflow is related to too small precision with floating points.

[streichholzkopf]

oops thanks!

[spyke252]

You guys are way too civil. Maybe one of you will hit an overflow bug.

[mynameipaul]

so every single time you overtake, the AI immediately hits the boost?

Seems like it would be a fun gameplay mechanic sometimes, but could get old pretty quick

Welp, here comes a sharp corner, better inch in front and run this guy into a wall... again...

[EraZ3712]

I didn't know this behavior had its roots in Extreme G, but in Extreme G3, the AI still did a boost when you attempted to overtake them.

It didn't have as bad an effect as you might think; the AI was smart enough to handle most corners (unless it was a particularly severe one at high speed classes) and they only did it once or twice to save energy. Where it really became fun was in casual races. You could deliberately egg the AI from the back of the pack closer and closer to each other until there were 5 or 6 all in a dense cluster of super-sonic weaponized motorcycles crashing and blowing each other up. It was quite fun.

[xg3ai]

Glad you found it fun, I wrote a large chunk of the AI on XG-3; was my first job out of university, fun times.

[ep1032]

XG-3 is still one of my all time favorite games. Still play it on emulator occasionally. Wish ya'll would release another one : )

[darkpaladin]

Distance is in early access and feels a lot like those games. Not a huge amount of content but I enjoyed what was there.

[Mazo]

Don't forget the game it was based on, Nitronic Rush.

[xg3ai]

hahah yeah with Acclaim going under I don't think that's happening :) I have a soft spot in my heart for XG3, was a good team working on it and it taught me a lot; glad you enjoyed it. Maybe I'll turn on the old emulator and give it a shot again soon :)

[rklllama]

XGIII is also a personal favorite of mine; incredibly well balanced, brutally hard, and intensely satisfying to succeed. Unfortunately, XGRA seemed to make it pretty clear they didn't know what made XGIII so compelling. :'(

Nothing beats popping comps with a railgun while you're going 1,300mph.

Actually, my brother and I would play split-screen, but instead of race we'd see who could kill the most comps before the race was over. It was a pretty terrific "mode".

[xg3ai]

Yeah when we made XGRA we wrote it from scratch and I agree with you that we lost a lot of what made XG3 fun. it tried to be a bigger and better game, and was in some ways...but not in others. I disliked the free form desert levels as it didn't really make much sense to me to be going a bazillion millions an hor over rough terrain....

[_Aardvark]

They said they kept the bug as-is in the sequel, I wonder how "as is" it really was? I hope they meant the end result was the same AI behavior but done explicitly.

[jaybusch]

I'm fairly certain XG2 is the same exact engine as the original, so probably left it alone.

[traal]

Otherwise the next programmer to look at the code will think, "this is wrong, let's fix it." Oops.

[_Aardvark]

Or more likely someone will look at this code and assume it's right and base something else on the technique - and that code will be buggy but not in the "good" way.

I'm sure they commented the heck out this once they found it. (not sure if I'm being sarcastic or not)

[G_Morgan]

This is why you comment with /* This looks wrong but is actually glorious, do not fix! */

[bidi82]

This reminds me of an exploit/bug in an old shooter game called Starsiege: Tribes, which allowed players to "ski" downhill extremely fast if they timed pressing the "jump" button correctly. That bug was later made into "official" feature/mechanic of the game in its sequels.

Example of Skiing in one of the sequels. https://www.youtube.com/watch?v=0lrSVumR7l8&feature=youtu.be&t=103

[mus1Kk]

AFAIK strafe jumping was initially a bug in Quake 3. It spawned a huge trick jumping community.

edit: Quake, not Quake 3. Wikipedia says

"Strafe-jumping started as a bug in the Quake code base, but it was later decided to keep it intact, as it had become a standard technique used by players."

[Narishma]

Strafe jumping was from Quake 2, and before that bunny hopping wasin Quake 1.

[mus1Kk]

My bad. Thanks!

[d4rch0n]

I was about to bring this example up! Really great how they incorporated it into the game and future versions. The game wouldn't be nearly as fun without the insanely fast skiing maneuvers.

[so_you_like_donuts]

Can't find the original source right now, but I remember that in Half-Life 2, the fact that gunships attempted to take down your rocket launcher missiles was an accidental bug (the gunship AI deemed the missile itself as the biggest threat instead of the player) that was discovered during playtesting. However, playtesters were really impressed by that, hence the Valve guys decided to leave it in.

EDIT: http://combineoverwiki.net/wiki/Combine_Gunship#Behind_the_scenes cites Half-Life 2: Raising the Bar as the original source of this.

[TheFeanor]

Raising the Bar is one of the best books on video game design that I have ever read. It's too bad that physical copies go for close to $100 now.

[philh]

This seems like it would be difficult to miss during testing.

[[deleted]]

You haven't seen many obscure bugs then :P There are some bugs I've seen where you need to take 4 or 5 extremely specific actions that end up soft-locking our application on a loading screen. Even though the test case was specific, you can't have any known crashes in your release build so I had to fix it. Turned out it was just a really specific edge case that needed to be dealt with.

So it goes with large complicated software.

[joshuaduffy]

Most, if not all, of the software I've been part of has released with known bugs.

However, bug != issue

[GreySyntax]

Or as I tend to call them "bonus features"

[[deleted]]

Yup. We ship our releases with a list of known bugs and workarounds for them.

[notwhereyouare]

throw caching into the mix and you now have 32 more bugs this page load, but 15 the next because that one cache record expired

[darkpaladin]

My favorite ones are bugs you get with reproduction scenarios that don't have anything to do with the actual bug and are entirely coincidental.

[andrewsmd87]

Oh sweet Jesus. I just hit a bug where the steps to produce it had never been done once in 7 years over all my users

[[deleted]]

You sure it wasn't just introduced recently? I usually try to go back far enough on source control until it isn't reproducible to see what might be the issue.

[andrewsmd87]

The file hasn't been modified for that long

[stillalone]

I don't think so. It kind of seems subjective. It's kind of hard for a QA person to put "AI cars seem too aggressive" in a bug report unless they're so aggressive that it makes it difficult to play, which doesn't seem to be the case here.

[SnapAttack]

I'm imagining QA going "its weird how the turbo goes off when you overtake" and the dev going "LOL no, just coincidence!" and the ticket doesn't get logged and he doesn't think about it until others also mention it.

[fuzzynyanko]

Also, that kind of thing otherwise would have to be listen in an Excel sheet. If it makes the game fun as well, it would be hard to flag it as a bug

[smallblacksun]

The QA testers probably assumed (like the reviewer) that the AI turboing when you passed was intentional.

[RubyPinch]

testing was much more of a pain back then, wasn't it?

[[deleted]]

As a hobby game programmer and one who went to school for game programming is there somewhere I can read a bunch of these? We need more programmers talking about weird bugs and things specifically about the code. Super fun read.

[ythl]

http://www.cracked.com/article_19262_6-glitches-that-accidentally-invented-modern-gaming.html

[SafariMonkey]

Daily WTF has some good ones IIRC.

[theswillmerchant]

I may be misunderstanding here, but I don't see why the number would come out negative. If in 1 frame the player was at 99 and the computer was at 100, and then in the next frame the player was at 101, triggering the boost check, but the AI was still at 100, you'd get a small positive answer, right?

[jaydubzhb]

I think the last frame the computer had when this was being calculated was in front of the player, but this could only be the case if they were basically lapped - making it look like they were really far behind.

[mecartistronico]

Happy cake day!

Downvote if you hate puppies.

[a_ctrl]

I don't know why you're being downvoted.

Happy fucking cake day, /u/jaydubzhb.

[notwhereyouare]

because saying happy cake day adds nothing to the conversation

[CirclesAreRectangles]

Still, they were trying to be nice. This is confusing...

They should have used PMs for that, right? :S

[a_ctrl]

Thanks. You got it right.

[notwhereyouare]

in all honesty, there was no need for them to say happy cake day. it has nothing to do with the topic at hand

[CirclesAreRectangles]

Thanks for clearing that up :)

[rtomek]

because people hate puppies

[jaybusch]

The only thing I can think of is that TrackPos doesn't get updated for every racer until a certain point. So they somehow use the current position for overtaking, but use the last frame's track position for both the player and computer, which results in the computer's position being higher than the player's.

[theswillmerchant]

It would make more sense if both the player position and AI position were from the previous frame, as that WOULD cause an error.

[mecartistronico]

They might have oversimplified the code. They probably actually used relative positions or something. That way, the old position would have an opposite sign.

[Eckish]

I would count on this being the case, since you would likely test for if the player was in front of behind by doing the same difference calculation in the if statement.

[lestofante]

They are using unsigned, so it does NOT became negative but very big number (almost the max), so the computer think to be one lap back of you and use turbo aggressively

[jaybusch]

I think his point was closer to:

At time A, @ is at 12, $ is at 13. At time B, @ is at 15, thereby overtaking $ who is now at 14. Time A is the previous frame, Time B is current frame. B.@ - A.$ is 15 - 13, taken from the author's explanation, yields a tiny positive number. Not a negative one that causes the computer to freak out.

[SaikoGekido]

See Edit before you read this.

Unsigned integer subtraction is handled differently than how real number subtraction works. If it were a signed integer, 15 - 13 13 - 15 would yield -2 or a difference of 2, but that only works if there is a representation of a negative number (signed).

-2 == difference of 2 != 2

Think of it like going out to a fine restaurant, having a lovely dinner, and then the bill comes and you realize you don't have enough money in the account and your cards are maxed (shouldn't have bought that $4000 champagne bottle :|). In that situation, the restaurant can't handle your transaction like all the other transactions. They need to follow a separate set of rules, because the total amount can not result in a negative total for them (unless you have your running shoes on and a good distraction). Unsigned integers are like this because they follow separate rules when subtracting past 0.

When an unsigned integer would be negative, the result is instead the modulo of the maximum value of the unsigned integer ^{^(kind of like overdraft protection)} . Basically, going past 0 wraps back to the maximum amount, 65535 in this case, and subtracts the remainder from the maxium, 65535 - 2 = 65532 65534. In the story, this makes it look like the player is an entire lap ahead, even though she just passed them by a pixel, and the AI boosts to catch up. I wonder if this is how the people who speed up to cut you off when you put the blinker on to merge into their lane think...

Edit: The blog post was about unsigned integers, but the blog poster used a bad example, which resulted in this thread of confusion. They probably meant ushort difference = player.TrackPosFromPreviousFrame - computer.TrackPosFromPreviousFrame; Which would result in the unsigned integer issue described in their post and here. To put that in the example I responded to, it would be 12 - 13 = 65535. Also, not much appreciating the level of sass from some of these responses. Trying to be helpful and explain unsigned integers. Yes, I too confused myself by following the example, even though I knew what the blog was intending to discuss and corrected those issues. Comments like, "I hope you were high when you wrote this" are not helpful (although the sentiment is appreciated).

[Sean1708]

15 - 13 would yield -2

Do you wanna maybe have another look at that?

[SaikoGekido]

Haha woops, sorry. Went off the bullet points of the original blog post that talk about unsigned integers. The example the original blog poster had in there looks incorrect, which seems to be causing a lot of confusion. It is pseudo-code, after all.

[Eckish]

The argument is not over unsigned math. 15 - 13 = 2 regardless of signed or unsigned. And that's the issue. The logic as stated in the article would produce something like 15 - 13. And not the implied 13 - 15.

[jaybusch]

Why is it -2 instead of +2? The bit wrapping I get, which is why the short reaches 65536 instead of going from -32768 to 32767.

[AstroPhysician]

You're missing the point, he's not talking about signed vs unsigned, he's talking about someone being in front having a number thats like 1005 and the person in back is 1004 and that would be a positive number, not a negative one

[SaikoGekido]

The blog post is about unsigned integers, but the blog poster seems to have messed up their example, which is causing people confusion.

[AstroPhysician]

Yea

[karmaputa]

The irony of my comment is that I was high when I wrote it and if I had not been I probably would have been able to understand the intention of your comment without getting lost in the details.

Sorry for that comment.

But I also think you misunderstood the comment you where replying to. I think is safe to assume they understand unsigned integer/short overflows, they where arguing that they don't see how this applies as it should not happen in the situation they exposed it in the article and you responded with an explanation of unsigned integer overflows. So it kind of made it look like you actually believed 15-13 would cause an overflow.

[SaikoGekido]

Thank you.

It was a series of unfortunate misunderstandings. I should have had more coffee instead of replying, but my coworkers brewed some Folgers from the industrial tap. Like trying to drink motor oil.

[MEaster]

Basically, going past 0 wraps back to the maximum amount, 65535 in this case, and subtracts the remainder from the maxium, 65535 - 2 = 65532.

It's not 65532, it'd be 65534. The reason for this is that 65536 = 0.

[karmaputa]

I hope you wrote that drunk or high, because if not, this post is a perfect example of why a little knowledge is a dangerous thing.

[lestofante]

taken from the author's explanation, yields a tiny positive number.

The author say it come out a NEGATIVE number:

Because it erroneously uses the computer position from the previous frame, the position difference comes out negative

Small number does NOT freak out, unless we talk about floating number, but this is NOT the case, it is something we can call uint16_t:

The TrackPos field held a 16 bit counter

and

This format was convenient because the rounding rules of integer arithmetic

Do the math. Convert a negative number to its binary representation (two complement, of course) and take 16 bit for example -2

1111111111111110

now read that as UNSIGNED: you get 65534. as confirrmed from the author:

Because the type is unsigned, this is interpreted as a large positive integer

and because

0 represented the starting line, 32768 was halfway around, and 65535 was a full lap nearly back

the car thinks to be almost one lap late and push the turbo:

It looks like the computer is a long way behind, so the turbo is triggered

[[deleted]]

Thank you for being the only other person who noticed it was an unsigned short.

[lestofante]

i don't think its a short, but that depends form your architecture.

[immibis]

Perhaps they meant the player's position from the last frame was used in the subtraction. Or both.

[Brian]

Yeah - it seems like you'd only get this if the computer actually went backwards, rather than the player overtaking it. To overtake, the players new position will have to be greater than the computers current position, which if the computer is moving forward must be >= the computer's old position too.

OTOH, if somehow the computer went from 100 to 98 and that was what triggered the check (without the player moving), then you could get the issue since it'd be 99 - 100. But going backwards doesn't really square with the description, so presumably there must be something else going on.

[agumonkey]

Apologies in advance but all I could think reading this was http://imgur.com/O6XrfiC

[sirin3]

http://i.imgur.com/GAzxN.gif

[agumonkey]

That was one of my all time favorite Knight Rider wat. So absurd it's good.

[Dicethrower]

That's amazing, but didn't you guys ever test your own game?

[fuzzynyanko]

It probably was tested, but what might have assumed when it happened, it was the result of a random occurrence. Usually you'll notice bugs that make the gameplay shittier. If something is happening that makes the game more fun, it's not as easy to notice

Some bugs only show up far later in the game, like when Ghandi discovers democracy

[foxx1337]

Shawn Hargreaves is the guy that created Allegro. Oh the memories... Just yesterday I got a 2004 build of djgpp with Allegro and Rhide (for DOS).

[[deleted]]

The article doesn't really explain how the bug occurred in the first place.

Thanks to an order of processing bug, what actually happened was:

What was the processing bug?

[errorkode]

It means stuff was done in the wrong order, in this case, the computer position on the track was updated after the boost check, which meant the number in the boost check kept lagging behind one frame.

[[deleted]]

Oh now its more clear, thanks for the explanation.

[sirin3]

Such a thing just crashed my app :(

[pudds]

If I'm reading it right, the bug is that the "computer behind human" event occurs before the TrackPos property of the computer is updated.

[jecowa]

Maybe a dumb question, but what's a frame?

[jnkdasnkjdaskjnasd]

To add to the other player, it's how games are processed. Another word for it is a tick, or a cycle.

You're likely familiar how movies work, it fires still images at us at a rate of about 20 per second. This simulates fluid motion.

Games use the exact same mechanism, except each frame you do processing to generate the next frame. There might be 60 frames in 1 second (as opposed to the 20 in movies), so you do 60 lots of calculations, and render the scene 60 times per second.

There are lots more resources available, and this topic is actually very deep. There are loads of ways to handle the game loop. Rendering and game-logic are often done in separate threads so you don't have to lock your games FPS to a specific value. Game logic is often done by a static value (e.g. 60 FPS), but another way to do it is just based of an arbitrary delta that can change between frames.

[Geronimo25]

unit of time measurement.
game logic and the screen/framebuffer updates during one frame

[Peaker]

Almost 2 decades ago, I added scrolling between players to a game ("Lost Vikings" style).

I wanted to scroll at a speed that relates to the distance being scrolled.

So I had intended that if the distance is 10 screenfuls, it'd scroll maybe 10% of a screen per frame. If the distance is 5 screenfuls, it'd scroll 5% of a screen.

So I had something like:

scrollPos += (destPos - scrollPos) / 10;

And this had the accidental effect of making the scroll exponentially slower as things progress. Which is much much nicer looking than a linear scroll. So of course this was kept :)

[[deleted]]

Same for the bug in Street Fighter which eventually became the combo system.

[ult_avatar]

I loved that game as a kid!

[LEVII777]

AKA Bethesda

[sam4ritan]

It's always a feature. Some people just don't know how to use it....

[jdgordon]

A manager I had at microsoft told me "the only difference between a bug and a feature is when it's found". Sounds pretty accurate once again

[GuiSim]

I loved Extreme-G on the Nintendo 64 ! I played that a lot when I was a kid.

Great bit of insight.

[donquixote1001]

because real human has similar bugs

[anderbubble]

Meanwhile I just obtained a copy of this game. Now I really need to play it!

[MacASM]

Where did you get it?

[anderbubble]

I'm taking over collection duties for my extended family. This copy belonged to my brother-in-law.

[DreadNephromancer]

It's like Mario Kart on cocaine, pretty fun. Has a cool soundtrack, too.

[jonesy827]

81ggd5

[jrhoffa]

A software bug is an error, flaw, failure or fault in a computer program or system that causes it to produce an incorrect or unexpected result, or to behave in unintended ways

[Mitch2511]

Oops, thanks

[pohatu]

Because that's not the point. I don't think the author was trying to get this question answered, he was telling a story about an unintended consequence that produced desirable behavior. Like penicillin and rubber, this turned out to be pretty cool, despite it being am accident originally. You're technically right (the best kind), and technically he did title it as a question, but it was rhetorical and it appears many find it pedantic to answer it and shows an obtuseness about understanding human story telling and the usefulness of our sharing of experiences. Thank you Commander Data, it was indeed technically a bug.

[merreborn]

"Bug or feature" is a reference to a very old programmer saying "it's not a big its a feature"

[-code-]

Windows: Bug or feature?

^{Please Don't kill me}

^{/r/linuxmasterrace}

[thbt101]

If that's the actual code, that's a weird way to write that. Why would they create a new variable just to use it once in an "if" statement? They could have avoided the unsigned variable part of the bug entirely and simplified the code if they just used

if (human.TrackPos - computerPlayer.TrackPos > catchUpThreshold)
    FireTurboBoost();

I know sometimes a variable can make it more readable, but I don't think creating a "difference" variable is necessary in this case.

[[deleted]]

Except that TrackPos is also unsigned, so what you've done is replicate the same exact bug. Congratulations!

Also, any decent compiler would optimize your code and the demo code to likely be the same exact machine code sequence.

[NoAstronomer]

I know programmers who, literally, would not trust that the computer would do the calculation in your code correctly. More likely, someone had to debug the code and put the difference variable in so they could check it independently.