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Intel Researchers Consider Ray-Tracing for Mobile Devices

Posted by Soulskill on Sun Mar 02, 2008 09:27 AM
from the smaller-pretty-pictures dept.
An anonymous reader points out an Intel blog discussing the feasibility of Ray-Tracing on mobile hardware. The required processing power is reduced enough by the lower resolution on these devices that they could realistically run Ray-Traced games. We've discussed the basics of Ray-Tracing in the past. Quoting: "Moore's Law works in favor of Ray-Tracing, because it assures us that computers will get faster - much faster - while monitor resolutions will grow at a much slower pace. As computational capabilities outgrow computational requirements, the quality of rendering Ray-Tracing in real time will improve, and developers will have an opportunity to do more than ever before. We believe that with Ray-Tracing, developers will have an opportunity to deliver more content in less time, because when you render things in a physically correct environment, you can achieve high levels of quality very quickly, and with an engine that is scalable from the Ultra-Mobile to the Ultra-Powerful, Ray-Tracing may become a very popular technology in the upcoming years."
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[+] Technology: Ray Tracing for Gaming Explored 266 comments
Vigile brings us a follow-up to a discussion we had recently about efforts to make ray tracing a reality for video games. Daniel Pohl, a research scientist at Intel, takes us through the nuts and bolts of how ray tracing works, and he talks about how games such as Portal can benefit from this technology. Pohl also touches on the difficulty in mixing ray tracing with current methods of rendering. Quoting: "How will ray tracing for games hit the market? Many people expect it to be a smooth transition - raster only to raster plus ray tracing combined, transitioning to completely ray traced eventually. They think that in the early stages, most of the image would be still rasterized and ray tracing would be used sparingly, only in some small areas such as on a reflecting sphere. It is a nice thought and reflects what has happened so far in the development of graphics cards. The only problem is: Technically it makes no sense."
[+] Games: Carmack Speaks On Ray Tracing, Future id Engines 256 comments
Vigile writes "As a matter of principle, when legendary game programmer John Carmack speaks, the entire industry listens. In a recent interview he comments on a multitude of topics starting with information about Intel, their ray tracing research and upcoming Larrabee GPU. Carmack seems to think that Intel's direction using traditional ray tracing methods is not going to work and instead theorizes that using ray casting to traverse a new data structure he is developing is the best course of action. The 'sparse voxel octree' that Carmack discusses would allow for 'unique geometry down to the equivalent of the texel across everything.' He goes on to discuss other topics like the hardware necessary to efficiently process his new data structure, translation to consoles, multi-GPU PC gaming and even the world of hardware physics."
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  • by click2005 (921437) on Sunday March 02 2008, @09:42AM (#22615114)
    Moore's Law works in favor of Ray-Tracing, because it assures us that computers will get faster - much faster - while monitor resolutions will grow at a much slower pace.

    Inverse Moore's Law states that the more time that developers spend on making games look 'pretty', the less time they spend on playability.
    • by koh (124962) on Sunday March 02 2008, @09:44AM (#22615122) Journal

      Inverse Moore's Law states that the more time that developers spend on making games look 'pretty', the less time they spend on playability.
      My psychic powers tell me you've played one of the recent Final Fantasy titles.

      • Re: (Score:3, Insightful)

        Sooner or later graphics that are completely indistinguishable from real life will be available on low-end hardware, then they'll have to start competing by making good games instead of just pretty games.
          • Re: (Score:3, Interesting)

            well i only play games on my mobile when i'm waiting for the bus or something. my point was that i tried some 3d racing games and some kind of 2d splinter cell clone but the only ones i actually feel like playing when i'm bored are a Zuma clone and 2 other simple games. maybe it's because i don't need to pay much attention or because i don't need time to understand how to play it. but i can't see why would anyone want to play a complex game on such a small screen and with those really bad controls.
    • by jcnnghm (538570) on Sunday March 02 2008, @10:01AM (#22615176)
      You could probably argue that is why the Wii is selling so well.
      • Re: (Score:3, Insightful)

        I would agree with that argument. The wii got me back into gaming after a few year break. I had quit because I was annoyed with games being all about graphics and not being fun enough to actually draw me in.
      • by Slarty (11126) on Sunday March 02 2008, @11:17AM (#22615442) Homepage
        For games, at least, shadows don't need to be perfect. Neither do reflection and (especially) refraction. The goal is all about rendering something that looks plausible, not perfect (although it's a bonus if you can get it). For things like caustics, most people (and especially gamers) just aren't going to notice if the shadows or caustics or what-not are a tiny bit "off".

        Current rasterization approaches use a lot of approximations, it's true, but they can get away with that because in interactive graphics, most things don't need to look perfect. It's true that there's been a lot of cool work done lately with interactive ray tracing, but for anything other than very simple renderings (mostly-static scenes with no global illumination and hard shadows), ray tracers *also* rely on a bunch of approximations. They have to: getting a "perfect", physically correct result is just not a process that scales well. (Check out The Rendering Equation on wikipedia or somewhere else if you're interested; there's a integral over the hemisphere in there that has to be evaluated, which can recursively turn into a multi-dimension integral over many hemispheres. Without cheating, the evaluation of that thing is going to kick Moore's law's ass for a long, long time.)

        By the way, the claim that with a "physically correct environment, you can achieve high levels of quality very quickly" doesn't really make much sense. What's a "physically correct environment" and what is it about rasterization that can't render one? How are we defining "high levels of quality" here? And "very quickly" is just not something that applies much to ray tracers at the moment, especially in the company of "physically correct". :-)
          • by Slarty (11126) on Sunday March 02 2008, @02:58PM (#22616630) Homepage
            Sure, the rendering equation isn't ray tracing specific (it's a core graphics equation, independent of any one image generation method) but it's much easier to directly apply in ray tracing. There aren't many rasterization techniques that even attempt to solve it... the goal usually is just to add some ambient light effects which look like a plausible attempt at global illumination. AFAIK, even the latest, greatest game engines still stop short at something like baked-in ambient occlusion or screen-space darkening using the depth buffer. It looks cool, but physically accurate it ain't. It's much more natural to get "perfect" results in ray tracing, but that was kinda my point: getting those accurate results is pretty costly. If people don't notice the difference, why bother? Stick with the cheap approximation.

            And about scalability, you're right, of course; ray tracing does scale better with scene complexity than rasterization does, and as computing power increases it will make more and more sense to use ray tracing. However, the ray tracing vs. rasterization argument has been going on for decades now, and while ray tracing researchers always seem convinced that ray tracing is going to suddenly explode and pwn the world, it hasn't happened yet and probably won't for the forseeable future. Part of it is just market entrenchment: there are ray tracing hardware accelerators, sure, but who has them? And although I've never worked with one, I'd imagine they'd have to be a bit limited, just because ray tracing is a much more global algorithm than rasterization... I can't see how it'd be easy to cram it into a stream processor with anywhere near as much efficiency as you could with a rasterizer. On the other hand, billions are invested into GPU design every year, and even the crappiest computers one nowadays. With GPUs getting more and more powerful and flexible by the year, and ray tracing basically having to rely on CPU power alone, the balance isn't going to radically shift anytime soon.

            For the record, although I do research with both, I prefer ray tracing. It's conceptually simple, it's elegant, and you don't have to do a ton of rendering passes to get simple effects like refraction (which are a real PITA for rasterization). But when these articles come around (as they periodically do on Slashdot) claiming that rasterization is dead and ray tracing is the future of everything, I have to laugh. That may happen but not for a good long while.
  • Brilliant! (Score:5, Funny)

    by neonmonk (467567) on Sunday March 02 2008, @10:23AM (#22615232)
    I can just see two moustached elderly gents discussing research, possibly even drinking Guinness out of a bottle. They go silent for a few minutes and then one of them, whilst stroking his long droop moustache suddenly jumps up and proclaims:

    "Holy Crap! Mobile gaming devices have tiny screens, imagine how easy it'd be to use advanced raytracing graphics!"
    "Brilliant!"
  • by nurb432 (527695) on Sunday March 02 2008, @10:45AM (#22615288) Homepage Journal
    "As computational capabilities outgrow computational requirements, the quality of rendering Ray-Tracing in real time will improve, and developers will have an opportunity to do more than ever before."

    This attitude is why even tho our computers are 1000x faster then we had 20 years ago, they actually perform worse overall.
    • Re: (Score:3, Insightful)

      This attitude is why even tho our computers are 1000x faster then we had 20 years ago, they actually perform worse overall.

      I would say yes and no. Its one thing to have the computer do something simply becase it can; I agree that is very wasteful. Raytracing is not needed on a 300x200 screen; especically while plaing a game and things are moving.

      On the otherhand 20 years ago like today we compormised and dispensed with things or found was to "fake it" in cases where the computer's conuld not deliver. Its really not critical shadows are rendered perfectly on my mobile phone while I am playing Doom57 Mobile Edition. An arch

  • prog10 (Score:5, Funny)

    by k2enemy (555744) on Sunday March 02 2008, @10:49AM (#22615300)
    Too bad the source code for the highly optimized prog10 raytracer was lost in the great hard drive crash of '98.
  • by DigitAl56K (805623) on Sunday March 02 2008, @10:50AM (#22615308)

    Moore's Law works in favor of Ray-Tracing, because it assures us that computers will get faster - much faster - while monitor resolutions will grow at a much slower pace.
    Where did this "assurance" come from? Display resolutions grow as quickly as the latest games can run smoothly at the leading-edge dimensions. Since Moore's law is about doubling processing power, but doubling the display resolution means quadrupling the number of pixels, you may find the relationship is in fact much closer than you'd think.
    • Re: (Score:3, Informative)

      Moore's Law says the number of transistors in a certain area at a certain cost will double about every 18 months. This effectively seems to double computer speed every 18 months.

      Doubling the number of transistors on an LCD does not double the resolution (as you pointed out), it only multiplies each dimension by the square root of 2. Doubling the number of transistors on a CRT does nothing (well, maybe it gives you a more impressive OSD). But even limiting it to LCDs, it does not hold up. Display resolution
  • by should_be_linear (779431) on Sunday March 02 2008, @10:51AM (#22615318)
    As Intel couldn't compete with ATI/nVidia on 3D rendering performance, they simply redefined rules of the game. Now they seem ahead of everyone else in Real Time Raytraycing, at least based on publicly presented papers. Now, they need to integrate this into some bigger picture of "new gaming platform". If they manage to integrate this graphics with Java JVM in coherent way, so that developers can easier utilize multiple cores in games and be able to write games once, run on all platforms/future consoles as a bonus. That would be big step towards letting developers focus towards gameplay and not on DirectX/OpenGL/PS3/... API generations, extension nuances, tricks for simulating shades, optimizing polygon count in big scenes, ... ray-tracing is making all this simple without requiring effort on developer's side. Yes, I know Java is some percents slower then C++, but in Java it is so much easier to utilize multiple-cores (especially when it comes to debugging) that I am sure performance will be gained, not lost on modern CPUs.
  • by binaryspiral (784263) on Sunday March 02 2008, @10:58AM (#22615348)
    This is kind of stupid actually. Why would I want a game on my mobile to be thrashing the cpu when it could be doing some basic sprites and other not-so-cpu-intensive methods to produce my game?

    Ray-tracing may be possible on my 500Mhz smartphone's processor - but damn, I don't want to have to be plugged in to play them.
  • Rendering my latest blender project....
  • by Grard Menfin (1178135) on Sunday March 02 2008, @11:19AM (#22615452)
    For those interested in real-time raytracing, the latest beta version of POV-Ray [povray.org] has a neat (but experimental) RTR feature. The source is now available for Windows and Unix/Linux. There also demo scenes available (and another demo scene with pre-baked textures can be found here [oyonale.com]).
  • by igomaniac (409731) on Sunday March 02 2008, @11:26AM (#22615504)
    If you want to know the future of real-time graphics, look at what Pixar and other animation and special effects houses are doing. None of them are using ray-tracing except to achieve specific effects in specific circumstances. The fact is that global illumination combined with scanline renderers simply produce better pictures with less computational requirements.
    • What does Pixar have to do with realtime graphics? Pixar's not DOING realtime graphics.

      Pixar has the luxury of controlling every take, and going back after the fact to re-render shots with different settings, or even to use different algorithms (including ray-tracing) to fix any rendoring flaws caused by whatever approximations they're using at that point. Realtime graphics do not have that luxury... if there's a problem in a scene, you can't go back and fix it.

      So whether raytracing is more or less appropri
    • Actually Pixar has switched to Ray Tracing. Cars was ray traced [pixar.com] [PDF]. Skimming through the whitepapers on the Pixar site [pixar.com], it's clear ray tracing was also used extensively in Ratatouille.

      Even so, what Pixar is doing in feature films isn't particularly relevant to real-time ray tracing on mobile devices.

      • It's worth pointing out (and it's mentioned in the paper you cite) that the main reason Pixar hasn't been doing much ray tracing until now is not performance or realism, but memory requirements. They need to render scenes that are too complex to fit in a single computer's memory. Scanline rendering is a memory-parallel algorithm, ray tracing is not. So, they're forced to split the scene up into manageable chunks and render them separately with scanline algorithms.

        This isn't an issue for games, which are going to be run on a single machine (perhaps with multiple cores, but they share memory).

  • by sunderland56 (621843) on Sunday March 02 2008, @01:23PM (#22616096)
    The normal way things work in computing, things tricke down from high-performance platforms to lower ones. So, where are the desktop games using raytracing?

    If they want a phone to do 256 x 192 raytracing in real time, then a desktop with 1000x the compute power should easily be able to do 720x480 (full res television) in real time. But, oddly enough, there are no such titles out there....
    • That phones may be able to ray trace is news? Sounds more to me like intel was of reading in the news all week how inferior their graphics stuff was because of the Microsoft Vista debacle part eight - and suddenly we have an anonymous tip to a blog at intel saying ray tracing on phones there is "an opportunity to deliver more content in less time" and "Ray-Tracing may become a very popular technology in the upcoming years".

      A popular technology? Like a working filesystem? They're real popular I hear. Or an o