Game Tech: How BioShock Infinite’s Lighting Works

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Original source An anonymous reader writes “The Principal Graphics Programmer for BioShock Infinite has put up a post about how the game’s lighting was developed. We don’t usually get this kind of look into the creation of AAA game releases, but the studio shut down recently, so ex-employees are more willing to explain. The game uses a hybrid lighting system: direct lighting is dynamic, indirect uses lightmaps, shadows are a mix. ‘Dynamic lighting was handled primarily with a deferred lighting/light-pre pass renderer. This met our goals of high contrast/high saturation — direct lighting baked into lightmaps tends to be flat, mostly because the specular approximations available were fairly limited.’ It’s interesting how much detail goes into something you don’t really think about when you’re playing through the game. ‘We came up with a system that supported baked shadows but put a fixed upper bound on the storage required for baked shadows. The key observation was that if two lights do not overlap in 3D space, they will never overlap in texture space. We made a graph of lights and their overlaps. Lights were the vertices in the graph and the edges were present if two lights’ falloff shapes overlapped in 3D space. We could then use this graph to do a vertex coloring to assign one of four shadow channels (R,G,B,A) to each light. Overlapping lights would be placed in different channels, but lights which did not overlap could reuse the same channel. This allowed us to pack a theoretically infinite number of lights in a single baked shadow texture as long as the graph was 4-colorable.'”

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Hour record regulations could see changes by mid-year

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Original source

Chris Boardman set a new hour record in Bordeaux, France, in 1993 on modern aerodynamic equipment. Photo: AFP

RICHMOND, Va. (VN) — The hour record may be getting a refresh this year, whether or not Fabian Cancellara makes good on his promise to pursue the long-stagnant benchmark.

Speaking with VeloNews at the Richmond 2015 course announcement on Tuesday, UCI president Brian Cookson revealed that the UCI Management Committee has tasked the organization’s track commission with reviewing and revising the regulations that govern the hour record. The track commission is expected to deliver its recommendations in the next several months, and Cookson expects any resulting changes to be adopted by mid-year.

“My own view is that the so-called athletes hour, the record on the old traditional track bike, I think it was a nice idea, but frankly I think it’s an idea whose time has passed,” Cookson told VeloNews.

The creation of the athlete’s hour was the UCI’s attempt to protect the hour record as a physical contest among men, as much removed from technology as an inherently technological sport could manage. It put the brakes on decades of technological advancement in record-setting technology — from Francesco Moser’s dual-disc funny bike to Graeme Obree’s radical and fast egg and superman positions — by limiting riders to a diamond-framed bike, shallow, spoked wheels, drop handlebars, and standard helmets.

The athlete’s hour may have removed technological variables to the extent possible, but it also all but killed interest in the record. Chris Boardman set the new record under the new rules in 2000, displacing Eddy Merckx, whose 1972 mark was reset as the official record. Since then, Boardman’s mark has only been topped by the relatively anonymous Ondřej Sosenka, the giant Czech winner of the 2002 Peace Race, who set the current mark of 49.7 kilometers in 2005 before exiting the sport on a methamphetamine positive in 2008. The athlete’s hour record has remained untouched since. Chris Boardman’s pre-athlete’s rules mark, set using the arms-out superman position pioneered by Obree and now known as the “best human effort,” still stands at 56.375 kilometers.

Faced with two parallel records and what its president views as outdated regulations, the UCI is left looking for the middle road between an anachronism and a technological battleground.

“So what we’ve asked the track commission is, look, what’s the step forward out here?” said Cookson. “We aren’t going to allow anyone to ride the hour record in the superman position. But we think that the old, traditional track bike athlete’s hour record is probably a little bit of an outdated idea. Where do we go from here?”

One likely solution would be to allow aspiring hour record holders to use current, UCI legal pursuit bikes, which, unlike current hour-record bikes, can use monocoque frames, deep section or disc wheels, and aerodynamic handlebars. But, with modern technology back in place, which mark would they be aiming for — Sosenka’s athlete’s mark, or Boardman’s ultimate hour?

Recent advances in training and technology mean that one of today’s riders on a modern pursuit bike might put the blazing marks achieved with the radical superman position within reach. In 2011 Australian Jack Bobridge, riding a pursuit bike, toppled Boardman’s 1996 4km individual pursuit record, set in the outlawed superman position and long considered unbeatable under current equipment rules. If that four-minute effort can be extrapolated to the hour, Boardman’s best human hour record could be a fair mark, yet one sufficiently difficult to narrow the field of riders who could claim what was once one of cycling’s crown jewels.

“I want to stimulate interest in the world hour record. I want people to go for that. But I want them to do it in a way that’s meaningful and sets a really high standard,” Cookson said. “I don’t just want to say, ‘OK, ride the pursuit bike and set a new record,’ because anyone could go and do that. Beating the athlete’s hour record on a current pursuit bike? I’m not going to say it would be a soft record, because it’s pretty hard to ride that speed for an hour, but it would be doable by a large number of athletes. What we have to do is find somewhere between the superman record and the athlete’s hour record that’s achievable by an athlete of stature and quality.”

With Fabian Cancellara stepping forward to express his interest in the hour, Cookson has an athlete of that stature and quality, but ultimately, he’d like to see a return to decades past, when the sport’s most formidable time trialists, men like Boardman, Miguel Indurain, and Tony Rominger, as well as innovator Obree, swapped the record amongst themselves.

“Yeah, [Cancellara] will be good. But you know, Tony Martin’s pretty good at riding fast on his own. Bradley Wiggins knows how to ride a track pretty fast. I’m sure there are others out there that would fancy having a go as well. I think we can see something really exciting coming.”

The impending rule changes could be responsible for Trek Factory Racing’s hesitation to set a firm date for Cancellara’s hour attempt. Setting a new athlete’s hour record under the current rules could make for short-lived glory if the hour is opened to modern technology later in the year. When contacted for comment, the The team’s press officer responded via email, saying, “We’ve also heard rumors that the UCI is considering changes to the hour record rules, but we have no comment on it right now.” did not return a request for comment on this story and said last week that the American squad would not address the hour record until after the spring classics.

In an era in which sports once considered “extreme” are now Olympic mainstays, can the ancient hour record — one man on a wooden track, steady on for 60 minutes — hope to recapture the fans’ imaginations?

“I was lucky to be present at both of Chris Boardman’s hour records and they were fantastic,” Cookson said. “Listen, anyone who says it’s boring watching a guy going around a track for an hour has never attended one. It’s absolutely brilliant. They were two of the best hours I’ve ever spent in a velodrome.”

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How An Astronaut Nearly Drowned During a Space Walk

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Original source Hugh Pickens DOT Com writes “About 44 minutes into a 6.5-hour spacewalk last July, Italian astronaut Luca Parmitano noted that water was building up inside his helmet – the second consecutive spacewalk during which he reported the problem. As Parmitano worked his way back to the air lock, water covered his eyes, filled his ears, disrupted communications, and eventually began to enter his nose, making it difficult for him to breathe. ‘I know that if the water does overwhelm me I can always open the helmet,’ wrote Parmitano about making it to the airlock. ‘I’ll probably lose consciousness, but in any case that would be better than drowning inside the helmet.’ Later, when crew mates removed his helmet, they found that it contained at least 1.5 quarts of water. In a 122-page report released Wednesday, a mishap investigation board identified a range of causes for the near-tragedy, including organizational causes that carried echoes of accident reports that followed the loss of the shuttles Challenger and Columbia and their crews in 1986 and 2003. Engineers traced the leak to a fan-and-pump assembly that is part of a system that extracts moisture from the air inside the suit and returns it to the suit’s water-based cooling system. Contaminants clogged holes that would have carried the water to the cooling system after it was extracted from the air. The water backed up and flowed into the suit’s air-circulation system, which sent it into Parmitano’s helmet (PDF). The specific cause of the contamination is still under investigation but investigators also identified deeper causes, one of which involved what some accident-investigation specialists have dubbed the ‘normalization of deviance’ – small malfunctions that appear so often that eventually they are accepted as normal. In this case, small water leaks had been observed in space-suit helmets for years, despite the knowledge that the water could form a film on the inside of a helmet, fogging the visor or reacting with antifogging chemicals on the visor in ways that irritate eyes. NASA officials are not planning on resuming non-urgent spacewalks before addressing all 16 of the highest priority suggestions from the Mishap Investigation Board. ‘I think it’s a tribute to the agency that we’re not hiding this stuff, that we’re actually out trying to describe these things, and to describe where we can get better,’ says William Gerstenmaier, associate administrator for NASA’s Human Exploration and Operations Mission Directorate. ‘I think that’s how we prevent Columbias and Challengers.'”

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