Table Of Content

T H E L E A D I N G G A M E I N D U S T R Y M A G A Z I N E V O L 1 9 N O 9 SS EE PP TT EE MM BB EE RR 22 00 11 22 I N S I D E : S C A L E Y O U R S O C I A L G A M E S 29 R 1E p o s t m o r t e m B 9m U 24 PixelJunk 4am 0N How do you invent a new musical instrument? PixelJunk 4am turned 9 .1 PthSe3irs p eevreforyrmwhaenrcee isn wtoo mrlduwsiicd-em. Iank tihnigs mpoascthminoerste amn,d l eleatd p dlaeyseigrns esrt rReoawma n SmE U Parker walks us through the ups (Move controls, online streaming), the TL o downs (lack of early direction, game/instrument duality), and why you NV need to have guts when you’re reinventing interactive music. By Rowan Parker E T f e a t u r e s N 7 Fight the lag! o Nine out of ten game developers agree: Lag kills online multiplayer, especially when you’re trying to make products that rely on timing-based c skill, such as fighting games. Fighting game community organizer Tony Cannon explains how he built his GGPO netcode to “hide” network latency and make online multiplayer appetizing for even the most picky players. By Tony Cannon 15 Scale Your online game Mobile and social games typically rely on a robust server-side backend—and when your game goes viral, a properly-architected backend is the difference between scaling gracefully and being DDOSed by your own players. Here’s how to avoid being a victim of your own success without blowing up your server bill. By Joel Poloney 20 level uP Your Studio Fix your studio’s weakest facet, and it will contribute more to your studio’s overall success than its strongest facet. Production consultant Keith Fuller explains why it’s so important to find and address your studio’s weaknesses in the results of his latest game production survey. By Keith Fuller d e p a r t m e n t s 2 gamePlan By Brandon Sheffield [editorial] Haters Gonna Hate 4 headS uP diSPlaY By Staff [newS] The indie-led wrestling genre revival, and games for cats 32 toolBox By Mike De La Flor [review] Wacom Cintiq 24HD Tablet Review 34 inner Product By Alex Darby [Programming] Programmers Disassemble! 43 good JoB By Patrick Miller [career] Q&A with Seth Killian, new studios, and who went where 44 Pixel PuSher By Steve Theodore [art] The Chopping Block 46 deSign oF the timeS By Jason VandenBerghe [deSign] The Care Bear Myth 48 gdc newS By Staff [newS] GDC Online Preview 50 aural Fixation By Damiam Kastbauer [Sound] Pop Will Eat Itself 51 BuSineSS By Dave Edery [BuSineSS] Free-To-Play Pitfalls 52 educated PlaY By Patrick Miller [education] Souvenir 56 arreSted develoPment By Matthew Wasteland [humor] The Gamemasons www.gdmag.com 1 GgAaMmEe PpLlAaNN //// BbRrAaNNDdOoNN SSHHEeFFFFIIEeLlDd game developer magazINe www.gdmag.com haters Gonna hate UBM LLC. 303 Second Street, Suite 900, South Tower San Francisco, CA 94107 t: 415.947.6000 f: 415.947.6090 DEaLInG wITH crITIcISM, anD wHy pLayErS LOvE TO HaTE wHaT THEy LOvE suBsCrIptIon servICes for InforMatIon, orDer QuestIons, anD Mass EffEct 3 was the cap to a hating on products really works. community, most likely because aDDress ChanGes trilogy of games that players had It gets results, or at the very least many in the indie game community t: 800.250.2429 f: 847.763.9606 come to feel emotionally invested reactions, and this has been are making games themselves. e: [email protected] in. They had maintained their absorbed into internet and geek Nobody wants their first big effort www.gdmag.com/contactus characters and character alignment culture at large. stomped on, and so a culture of eDItorIal through dozens of hours of play, Here’s another recent example support is bred instead of one of puBlIsher and the internet was rife with in games. Journalist Patrick Klepek negative reinforcement. Simon Carless e: [email protected] speculation about where the story recently lost a close relative, But it’s interesting to watch eDItor-In-ChIef could go. Then they finished the which greatly affected him, and he these indies as they climb. Brandon Sheffield e: [email protected] game—and by gum, some vocal briefly spoke about it publicly. Not Self-starters like Zeboyd Games eDItor Patrick Miller e: [email protected] people sure hated that ending. long after, Klepek wrote an article were lauded early on for their ManaGer, proDuCtIon So BioWare read the vitriolic that some people disagreed with, revisionist Japanese-style RPGs, Dan Mallory e: [email protected] comments, listened to the including one person who saw fit to but as soon as they started to art DIreCtor petitions, and made a new ending comment, “I’m glad someone close work on a large property (Penny Joseph Mitch e: [email protected] that tried to address some of these to you died.” Arcade’s On thE Rain-slick ContrIButInG wrIters Tony Cannon, Joel Poloney, Rowan Parker, Mike concerns. And guess what? The Klepek was quite affected by PREciPicE Of DaRknEss: EPisODE De La Flor, Alex Darby, Steve Theodore, Jason haters still hated it. We, collectively, this terrible statement, of course, 3), the criticisms and negativity VandenBerghe, Damian Kastbauer, David Edery, have created a game community and wrote about it on his blog. started streaming in. Once you’re Matthew Wasteland that thrives on hate, and Now, I’m not saying he shouldn’t rolling with the big boys, it’s time aDvIsory BoarD sometimes there’s not much you have addressed it, but fewer to get your shields up. Mick West Independent Brad Bulkley Microsoft can do but grow thicker skin. people would write a blog post As an indie, showing your work Clinton Keith Independent about how they had gotten some early and often wins you points Brenda Brathwaite Loot Drop I love to hate you awesome praise from a random with your friends and your fans, Bijan Forutanpour Sony Online Entertainment »The engagement we have with internet denizen. By and large, we and people will be very supportive Mark DeLoura THQ Carey Chico Globex Studios the community is a double- as an industry reward negative of you. But when you’re BioWare, Mike Acton Insomniac edged sword. It is fantastic (and comments with more attention and you change a character’s armor aDvertIsInG sales necessary) to get fan feedback than we give positive ones. slightly, you’re going to get some and make people feel involved Very often, when I address a praise, and a bunch of hate. And as GloBal sales DIreCtor in a product. But the internet negative sentiment that’s been left I mentioned before, we’re trained Aaron Murawski e: [email protected] t: 415.947.6227 is the “great equalizer,” and on my articles, or levied toward to seek out that hate, and to give it MeDIa aCCount ManaGer WeedSmokeBalls187 now feels his me personally, especially if I do it greater privilege than the love we Jennifer Sulik e: [email protected] voice is as important as that of a directly via email, the person will receive. It’s terribly hard to avoid. t: 415.947.6227 work’s original creator. The ease of backtrack, saying, “Oh my god, I GloBal aCCount ManaGer, reCruItMent expressing opinion on the internet love your stuff. Thanks for replying. It’s alIve! Gina Gross e: [email protected] t: 415.947.6241 makes it easy for everyone to feel I’m sorry if I seemed rude, I was just »This is a monster that we as GloBal aCCount ManaGer, eDuCatIon their voice is as important as any thinking this and that...” The hate is professionals have bred and Rafael Vallin e: [email protected] other, and the loudest voice will expressed deeply, but is really only allowed to flourish. Community t: 415.947.6223 often become popular opinion. on the surface. It’s born out of a managers have tried to mitigate it aDvertIsInG proDuCtIon Then there’s how creators deeper need for connection. with information leaks to fans, and proDuCtIon ManaGer react. A comment saying “Wow, People love to hate the things many developers have had blowups Pete C. Scibilia e: [email protected] I love this!” doesn’t get as much they love. And why not? If they about this very issue. Ignoring t: 516-562-5134 attention as “God, this is terrible.” care about something deeply, any your fans is never the answer, and reprInts Everyone, game developers and minor detail will stick in their craw, silencing voices of dissent is not journalists included, responds and they’re more likely to get a very democratic. WRIGHT’S MEDIA Jason Pampell e: [email protected] quicker and with greater force response from the people who I don’t think anyone has found t: 877-652-5295 to negative reinforcement than made the thing they like, if they the ultimate answer. My advice is to auDIenCe DevelopMent positive. The squeaky wheel gets make a stink about it. We reward ignore the hate publicly at first, but the grease, and to a voice that it, directly. discuss it internally to see whether auDIenCe DevelopMent ManaGer wants to get noticed, that’s a it has merit. If it’s something you Nancy Grant e: [email protected] powerful piece of knowledge. the power of the prevIew should really address, speak to lIst rental Peter Candito I don’t think this is something »There’s one big exception to this those concerns as though they Specialist Marketing Services people do on purpose, but the haterade trend in games, and were well reasoned and nicely t: 631-787-3008 x 3020 more reactionary statements that’s the indie darlings of the written. But whatever you do, don’t e: [email protected] are made, and actions are taken world. The indie game community feed the trolls. ubm.sms-inc.com based on negative comments, is generally much more open and —Brandon Sheffield the more we show people that supportive than is the triple-A game twitter: @necrosofty 2 game developer | September 2012 www.uBM.CoM HEADS-UP DISPLAY IT’S REAL TO ME INDIE WRESTLING GAME DEVS ADD NEW LIFE TO THE GENRE //////// Wrestling games are largely a one-company genre; if you have the WWE license, you’re making the biggest game in town. But when wrestling fans aren’t satisfied with where the big game is going, it’s up to the independent developer to turn the match around. Game Developer spoke with WRESTLING REVOLUTION developer Mat Dickie about the nascent indie wrestling revival. I can’t think of any other sport or license where the contrast between the mainstream view and the independent view is so stark. PM: Do you think the wrestling market could support more devs and more games? MD: The wrestling demographic has always been good to me professionally, because you have a small but passionate audience who are prepared to invest in the entertainment they love. That’s what fi rst motivated me to make wrestling games for PC. Each platform is dominated by WWE primarily, but there’s a heart-shaped hole where an independent can make his presence felt. PM: Are you working in in-app purchases? MD: That business model would be the holy grail for us because wrestling games are bursting with content that could be monetized, while still making the fundamental gameplay available to all. It’s defi nitely something I’ll be investigating in WRESTLING MPIRE. Inset: ACTION mobile. That said, I like to keep things simple, so ARCADE WRESTLING. we’ll have to see if it’s a headache to manage. As a solo developer, I have to pick my battles carefully. Patrick Miller: Who are the main players in we’re going about it in our own unique ways this indie wrestling revival? so there is no competition. Collectively, we’re PM: How is it going from a primarily console- Mat Dickie: Ten years ago, Dave Wishnowski bringing independent content to separate based game niche to mobile? started a movement called Wrestling Gamers corners of the industry. MD: You can’t fully recreate a console game United in response to what he and many others on a smaller device, so you have to consider saw as the mainstream developers’ collective PM: How did this indie wrestling revival start? what sacrifi ces you’re willing to make. I made a mishandling of the genre. He put his money MD: Well, we are all disappointed with the state conscious decision to rediscover my 2D roots where his mouth was and bankrolled a project of mainstream wrestling games. We thought that and put gameplay at the forefront. A lot of of his own called PRO WRESTLING X, which he’s THQ had a winning formula with WWF NO MERCY longtime fans felt that 2D was a step backward hoping to release soon. Meanwhile, Dave Horn’s on Nintendo 64, which had inherited a Japanese for me, but I could either make an unplayable ACTION ARCADE WRESTLING is available on the game engine. When THQ took the license in their 3D game or a playable 2D game. Sometimes Xbox Live Indie Games Marketplace, and he own direction, a lot of diehard fans had to endure you have to go backward to go forward! has started work on a second, more ambitious games that looked the part but lacked substance The whole transition has actually been a installment. Dan Hinkles of Serious Parody has and playability. Dave Wishnowski has said he is blessing for me because I seem to have found secured a £1m ($1.56 million) investment in trying to recapture the golden era of Nintendo 64 my place. When I was making big 3D games his WRESTLING MANAGER project for iOS. Finally, with his PRO WRESTLING X. for PC, all people did was make unreasonable I have released the WRESTLING MPIRE series on comparisons to mainstream releases. WRESTLING PC and WRESTLING REVOLUTION for Android, and I PM: Is there anything you get to do with your REVOLUTION is an intentionally retro project, so have an iOS version in the works. wrestling game as an indie that a licensed everybody gets it and accepts it for what it is. dev can’t? Also, players have fewer preconceptions PM: Do you consider each other colleagues, MD: Our independent games depict a fi ctitious about how things should work. It wasn’t easy to or competitors? universe where anything can happen and squeeze so many commands into a few swipes MD: The way I see it, Dave Wishnowski caters creativity outranks commercial obligations. I get and pinches, but I feel I’ve delivered something to PC, Dave Horn caters to Xbox, Dan Hinkles a kick out of taking things behind the scenes and that goes beyond a gimmick and has become a caters to iOS, and I’m getting the best out exposing the realities of the business. A licensed credible way of engaging with wrestling. of Android. We’re all on the same page, and product could never go that far behind the curtain. –Patrick Miller 4 GAME DEVELOPER | SEPTEMBER 2012 HEADS-UP DISPLAY GAMES FOR CATS TIPS FOR FELINE-FRIENDLY DIGITAL AMUSEMENTS The two-man team of artist TJ Though it isn’t huge (yet), ddiiffffeerreennccee bbeettwweeeenn Fuller and programmer Nate there is now a legitimate market lliigghhtt aanndd ddaarrkk.. Murray at developer Hiccup had for video games aimed at felines. TToo ttaakkee aaddvvaannttaaggee something of a fl op with their So we sat down for a quick phone ooff tthhiiss,, GGAAMMEE FFOORR CCAATTSS video game debut: JACOB’S SHAPES, chat with Fuller for a list of best eennssuurreess aa hhiigghh lleevveell a simple iPad puzzle game aimed practices behind what makes ooff ccoonnttrraasstt bbeettwweeeenn at children. Perhaps children GAME FOR CATS tick. tthhee ttaarrggeett aanndd tthhee weren’t their forte. Perhaps they bbaacckkggrroouunndd,, nnoo mmaatttteerr needed a new audience. 1 // SUBTLE, NATURAL wwhhiicchh ggaammee mmooddee aa Noticing several YouTube MOVEMENTS ccaatt iiss ppllaayyiinngg.. TThhee llaasseerr videos of cats pawing at iPad Cats can detect subtle movements lleevveell ooffffeerrss aa bbrriigghhtt llaasseerr games (the human-focused kind), better than we can. If a cat oonn ttoopp ooff aa ddaarrkk bbaacckkggrroouunndd,, Fuller decided to try to make a doesn’t sense that its target is ffoorr eexxaammppllee,, wwhhiillee game specifi cally aimed at them— “alive,” it’s going to ignore it. The iinn aannootthheerr mmooddee,, aa something that could be produced fi rst attempt at movement in ddaarrkkllyy ccoolloorreedd mmoouussee and put on the App Store quickly so GAME FOR CATS was done purely ssccuurrrriieess aattoopp aann aallmmoosstt they could go back to making “real” through code, but everything ooffffeennssiivveellyy bbrriigghhtt wweeddggee games. The resulting game has “felt way too mechanical,” Fuller ooff cchheeeessee.. one simple mechanic: an object tells us. 33 //// CCAATTSS LLOOVVEE DDLLCC 44 //// NNOO PPAAUUSSEE FFOORR Like many mobile games, GAME PAWS FOR CATS is a free download that Hiccup wanted to implement a way monetizes itself with in-app for humans to pause the game transactions: specifi cally, the (allowing them to switch levels or, download includes the laser level perhaps, tweet kitty’s high score), for free, and offers the mouse but doing so in a way that prevented level for an optional 99-cent cats from pausing the game transaction. themselves was a design challenge. Unfortunately, the initial The solution, according to release of the game made Fuller, “still isn’t perfect”; that that purchase path a little too humans have to tap a specifi c easy; in the days immediately section of the screen fi ve times following the game’s release, cats in rapid succession to pause the everywhere were accidentally game. It works pretty well, but purchasing the 99-cent level Fuller says that cats still set it off without their owners’ permission. by accident occasionally. “We got in a lot of trouble,” Gamasutra mascot Tony Cifaldi tests GAME FOR CATS. Fuller laughs. “People were 5 // REWARD WITH on the screen (either a laser light, The solution was to throw accusing us of tricking cats into A SOUND a mouse, or, in the latest update, out that code and record finger making purchases. We got a ton Whenever a cat successfully a butterfl y) moves around the movements on the iPad. When of comments on our iTunes page scores in the game (in other screen in lifelike patterns, enticing the laser (or mouse) moves [from] people accusing us of words, touches the moving the cat to touch it. Cats are scored around in the game, creeping trying to rip them off.” target), its score increases and a on their performance, and the around slowly one moment The solution was to implement sound plays to reward the cat and game even incorporates Game and darting offscreen the a test to make sure the purchaser keep it engaged; the laser chimes, Center, to make sure kitty’s best next, that’s programmer Nate is human before the charge is the mouse squeaks in terror. scores are saved for all to see. Murray’s finger emulating life. allowed to go through. Specifi cally, Fuller warns that while there Just three weeks and one the purchaser is asked to place is temptation to have music in playtest at a local animal shelter 2 // HIGH-CONTRAST a hand on the screen and hold it the game, he thinks it would have later (neither Fuller nor Murray VISUALS there while the app “scans” it. In ruined this effect. are cat owners), GAME FOR CATS There is still some debate as reality, the game makes sure that “If there’s music playing, they debuted, drawing major media to exactly what cats can and four fi ngertip touch points don’t wouldn’t hear it,” he says. “The attention and enough sales to cannot see in terms of color, move for a few seconds—a test sound has to be meaningful, and justify both a sequel and several hue, and saturation, but no one even the craftiest of cats would with purpose.” copycats (pun intended). disagrees that they can tell the have a hard time circumventing. –Frank Cifaldi WWW.GDMAG.COM 5 m o c e. n gi n e al e r n u w. w w Unreal Engine 3 Kinects camera placement was done by noting camera complete and cohesive,” said Edwards. “There is a location and facing vectors and interpolating be- real sense of scale and place with many magnifi cent with Fable: The Journey tween them with script, which was a slow and clunky vistas and always a sense of traversing a huge land.” process. Being able to craft cutscenes in Matinee Lionhead Studios is embracing Microsoft’s Kinect gave the team much more control and The development process to bring Kinect functional- for Xbox 360 with its latest Fable game. Fable: The really empowered them to fi nesse their work. ity to life was a smooth one. The team ensured that Journey is set a few years after Fable 3 and unveils they had Kinect initialized and updated at the correct a brand new area of Albion to gamers. Edwards said a couple of the nine level design team points and that the interfaces were clear enough for members had Unreal Engine experience. For the the gameplay and level scripters to use in UE3. Players take control of Gabriel, an outsider who rest it was a pretty gentle learning curve. becomes a hero as a result of the seer Theresa, “The Unreal Developer Network (UDN) has been an who has been in the background of previous Fable “The nature of the game means we didn’t need to invaluable resource for us in both discussing com- games. The new game, which was developed using get right under the hood and bang our heads on the mon issues among developers and Epic, but also Unreal Engine 3 (UE3), was designed from the bonnet,” he said. for getting quick answers and resolutions using the ground up to fully embrace Kinect technology. forum history and the combined knowledge of the Edwards said the level design team used Matinee other developers using it,” said Lynn. “Kinect gave us the chance to let the player feel and Kismet to quickly block out puzzles and more involved with the world,” said Charlton environmental animations so they could get their With the game nearing completion, the team is Edwards, lead level designer, Lionhead Studios. “It vision across and try out ideas without just showing happy with what they’ve been able to accomplish. gave a physicality to some interactions that a button someone something scrawled excitedly on a piece simply can’t replicate. of paper. “It is a lovingly hand-crafted world, and we have tried hard to marry a lot of detail with the need to keep the According to Ben Brooks, senior scripter, Lionhead “My main reason for choosing UE3 was tools and frame rate high,” remarked Edwards. Studios, the company’s level design and gameplay iteration,” said Marcus Lynn, technical director, Lion- scripting teams – 19 members in total – worked head Studios. “I wanted to get a smile back on the After three successful RPG adventures in the Fable much more closely together on this game than previ- faces of content creators again where they wanted to series, Lionhead Studios hopes players will embrace ous Fable titles because the Unreal Engine’s toolset go and improve something and feel like they had the the same type of innovation it pioneered in console united these disciplines in a way that the studio’s old support and tools they needed.” games with Kinect technology. tools didn’t. Lynn said his team started the evaluation with a Thanks to Lionhead for speaking with freelance “Our level design and gameplay scripting teams skeletal team and quickly got up-to-speed on most reporter John Gaudiosi for this feature. have used Unreal Kismet extensively – it’s our aspects at a basic level. New engineers on the proj- primary tool for bringing the world to life,” explained ect were given a two-week period to write something Brooks. “It’s allowed us to very rapidly prototype, and fun using UE3, which proved successful. UPCOMING EPIC ATTENDED EVENTS the visual interface has opened up quest creation to Escapist Expo people who might view themselves as non-technical. Lionhead adopted additional Unreal Engine technol- Durham, NC The accessibility of the tools has really helped us be ogy tools such as Unreal Landscape and the foliage September 14-16, 2012 self-reliant as a team.” system, which helped reduce memory overhead and MIGS improve performance. Montreal, Canada November 13-14, 2012 Brooks said that Unreal Matinee, in particular, was something of a revelation. On previous games, the “We have managed to create a world that feels Please email [email protected] for appointments © 2012, Epic Games, Inc. Epic, Epic Games, Unreal, Unreal Developer Network, UDN, Unreal Engine, UE3, Unreal Kismet, Unreal Landscape and Unreal Matinee are trademarks or registered trademarks of Epic Games, Inc. in the United States of America and elsewhere. All other trademarks are property of their respective owners. All rights reserved. T o n y C a n n o n >>> www.gdmag.com 7 S ome of the best multiplayer arcade games on consoles or PC are absolutely ruined by lag when played online. It’s easy to understand why; if you’re playing a game that rewards precise timing and control (such as brawlers, shoot- ’em-ups, and fighting games, for example), you want your experience to be as close to lag-free as possible, or the game will feel like no one is playing as well as they think they should. In this article, I’ll walk through how I designed my GGPO netcode (short for “Good Game, Peace Out”), which was used in SKULLGIRLS, STREET FIGHTER III: 3RD STRIKE ONLINE EDITION, and plenty of emulated arcade games through the FinalBurn Alpha emulator. It’s handy for devs looking to mask and minimize the effects of lag in online multiplayer—particularly in games in which timing-based skill is key. GGPO is compatible with all arcade-style games that meet the following criteria: 1) Each update to the game simulation state must be deterministically derived solely from the player inputs and the previous simulation state, 2) the game must be able to update its simulation state independently of sampling the controller, rendering the video, or rendering audio, and 3) the game must be able to save and load the simulation state and execute on demand. GGPO handles all the details. The game developer simply needs to modify her game loop to allow for speculative execution. IDENTIFYING THE CHOKEPOINT NETWORK LAYER INPUT LOCAL INPUTS 1 INPUT The most common method of bringing FRAME 1 REMOTE INPUTS 2 multiplayer games online is to run a separate simulation on each console and keep them INPUT LOCAL INPUTS 2 INPUT synchronized by ensuring that each simulation REMOTE INPUTS 2 gets exactly the same inputs (see Figure 1). If GAME STATE the simulations are determined solely by the INPUT LOCAL INPUTS 3 INPUT inputs, playing the same inputs on both consoles REMOTE INPUTS 3 will result in the same output. This method has a lot of plus sides to it; computers are by INPUT LOCAL INPUTS 4 INPUT nature deterministic and most arcade games REMOTE use integer math exclusively, which is very well P1 + P2 MERGED INPUTS 1 INPUTS 4 behaved from processor to processor, and the INPUT LOCAL INPUTS 5 INPUT developer is also completely isolated from the FRAME 2 GAME STATE REMOTE details of the network implementation. Aside from P1 + P2 MERGED INPUTS 1 INPUTS 5 making sure the game runs deterministically, INPUT LOCAL INPUTS 6 INPUT the engineers and designers implementing the FRAME 3 GAME STATE REMOTE gameplay can be isolated from the details of the P1 + P2 MERGED INPUTS 1 INPUTS 6 network engine. This means you can retroactively add online multiplayer support to games that FIGURE 1: Implementing network play with the traditional frame-delay method. have already been released. (If you can provide a machine emulator for the original hardware GGPO.NET the game was written on, you don’t even need to rbeacsoemd pciolem ipt!o)n Feinntasll ays, itdheis f rmomet hao md ehtahso dn ore sqeurivreerd- INPUT LOCAL INPUTS 1 INPUT FRAME 0 GAME STATE PREDICT REMOTE for basic matchmaking, which is usually provided P1 + PREDICTED INPUT INPUTS 2 by the console manufacturer. Unfortunately, this method also comes with INPUT LOCAL INPUTS 2 INPUT one major drawback: These games are usually FRAME 1 GGAAMMEE SSTTAATTEE PREDICT REMOTE P1 + PREDICTED INPUT INPUTS 2 designed to sample the controller input before every simulation state update. A simulation INPUT LOCAL INPUTS 3 INPUT frame in the game cannot execute until all the FRAME 2 GAME STATE PREDICT REMOTE P1 + PREDICTED INPUT INPUTS 3 inputs from remote players have been received. In practice, this manifests itself as an input delay INPUT LOCAL INPUTS 4 INPUT equal to the time it takes to send a packet from FRAME 3 GAME STATE PREDICT REMOTE one console to the next. In short, the games lag. P1 + PREDICTED INPUT INPUTS 4 The instant response the game was designed for INPUT LOCAL INPUTS 5 INPUT is replaced by a sluggish and squishy control that FRAME 4 GAME STATE PREDICT REMOTE can ruin the players’ experience. P1 + PREDICTED INPUT INPUTS 5 In many cases, the delay introduced by the INPUT LOCAL INPUTS 6 INPUT networking layer can completely change the feel FRAME 5 GAME STATE PREDICT REMOTE of the game. In STREET FIGHTER, we call them “lag P1 + PREDICTED INPUT INPUTS 6 tactics”: using the knowledge that by the time your opponent sees your move it will be too late FIGURE 2: Breaking down GGPO’s prediction mechanism. 8 GAME DEVELOPER | SEPTEMBER 2012