Real-time Raytracing For PC Games Almost A Reality

Vigile writes "Real-time raytracing has often been called the pinnacle of computer rendering for games but only recently has it been getting traction in the field. A German student, and now Intel employee, has been working on raytraced versions of the Quake 3 and Quake 4 game engines for years and is now using the power of Intel's development teams to push the technology further. With antialiasing implemented and anisotropic filtering close behind, they speculate that within two years the hardware will exist on the desktop to make 'game quality' raytracing graphics a reality."

Comments

Big improvement on the way

[ackthpt]

Or is it? Simply means games will appear more eye-candy than they currently are. Gameplay will not change. EA will continue to use take last years sport game, through some new people into it, perhaps introduce some bug which makes it unusable and peddle it as The New Deluxe Edition. I wonder how many geometric objects it will be able to handle (and whether it handles transparancy with textures and patterns well) Having done a bit of raytracing I'm familiar with how quick things can bog down. It'll probably be a bit clunky at first, but get much better as horsepower and horsepower/dollar ratio improve.

There was some game I played on an Amiga (got that? A really old computer) where I raced around in an aircar zapping stuff (some bastard borrowed the game and I've never seen it since!) Very nicely rendered graphics, beautiful even, nearly looked ray-traced. Must have been about 15 years ago.

While I look forward to more realistic, or creative and beautiful gamescapes, do keep in mind -- we were all blown away by the first high quality animated films, now almost everything animated is rendered, raytraced, etc. and there's a lot of junk out there now. So this will be exciting for about 2 years then become "meh".

Lastly, they've got to get the motion down. Characters in games, including sports, look so damn wooden in their movement! That's where real improvement needs doing.

Re:Big improvement on the way

[morgan_greywolf]

The more the hardware can do for you, the less developer resources you need to spend on getting shadows and reflections to look good. The less developer resources spent on BS means that you can spend more developer resources on things like improving gameplay. Maybe EA won't do it (they don't strike as a very innovative company anymore), but somebody will.

Re:Big improvement on the way

[AKAImBatman]

Simply means games will appear more eye-candy than they currently are. Gameplay will not change.

Untrue! Ray Tracing is a lot more flexible method of rendering than previous engines have allowed. Many engines have claimed features like "destructible levels and terrain", but the engines were never fast enough to give both the eye candy demanded by the market and an engine capable of such free-form interaction. Ray Tracing could change all that. Programmers could no longer be limited by BSP trees, visibility trees, polygon count, and other requirements imposed on traditional engines.

Graphics-wise, ray tracing could open new doors as well. For example, 3D adventure games haven't really taken off because it's harder to insert clues in the areas. A painting on a wall, for example, will tend to be slightly too blurry to see a clue embedded in it in a true 3D environment. Ray tracing allows for more precise rendering that would make the painting crystal clear from all perspectives and distances. Which means that the game designer could actually make it visible that the subject of the painting is pointing at a hidden door without making it so obvious that it destroys the enjoyment of the puzzle.

What I'm getting at is that graphics improvements have been one of the factors that have allowed game creators to explore new game genres in the past. While the 3D-age has often focused on rendering quality to the point of forgetting the purpose of graphical improvements, that's not to say that a major switch in technologies couldn't bring new gaming experiences with it.

Re:Big improvement on the way

[joshv]

"Raytracing is O(log n) versus O(n) for rasterization, which means that even though raytracing is currently slower (the constants involved in raytracing are higher), after the break even point is passed much less of the available computational power will be needed to render the scene and can instead be used for physics and AI."

Not disagreeing with you here, but what's "n"?

Re:Big improvement on the way

[*weasel]

The canned solutions include precalculated light maps, mostly-static light sources and level designs that are carefully constructed to limit overdraw. The push for raytracing is more about removing the drawbacks of the current 'solutions', than notably improving eye candy.

E.g. raytracing solutions will free up developers to implement more-dynamic scenes, more-dynamic lights and level designs where buildings and cities aren't glorified mazes where 90% of the architecture is an impenetrable facade.
(Sure, some titles feature those sorts of things now - but they're expensive tricks, with severely limited implementation)

Re:Big improvement on the way

[slew]

So then, in a ray-traced environment, couldn't developers just install virtual stage lights in the environment to re-create TV and movie lighting in the gameplay? Sort of the same way that Nintendo made the Zelda game look like it was animated?

In case that wasn't clear in my response, developers do use virtual stage lights to make shadows look good in ray-traced environments (just like they do it in triangle rendered environments).

The time spent is in tweaking the location of those virtual lights to get shadows to look right, so that's not an "advantage" of ray-tracing. You could use a dumb grid of lights in both ray tracing and triangle rendering or you could spend a month putting the light in to get the shadows to look just right, the time is in the placement and intensity of the lights, not the rendering technique.

Re:Big improvement on the way

[uhlume]

Where's my -1, Improper/Excessive Use Of "Scare" Quotes mod?

This isn't a semi-literate junior high textbook, you don't need to highlight the important terms for us -- we're perfectly capable of figuring those out from context, thanks.

But yes, you're absolutely right about the necessity of lighting design to create dramatic lighting even with raytraced rendering. Most modern 3d-accelerated raster technologies are similar enough to raytracing in their effect that environmental lighting workflows shouldn't change dramatically with the introduction of real-time ray-tracing. The more interesting implications lie in real-time dynamic lighting effects on NPCs and objects: when everything in the scene is capable of casting and receiving shadows -- and reflections -- a whole world of subtlety and nuance in gameplay and storytelling is opened up. Imagine playing an FPS, catching your opponent's reflection in a metallic object nearby, just in time to dodge his attack. Or seeing a shadow approaching from around the corner, giving you time to hide in a darkened corner nearby -- then inadvertently giving yourself away when a glint of reflected light off of your visor catches your opponent's eye. We've already gotten a taste of this sort of thing in games like Doom 3, F.E.A.R., and BioShock, but raytracing throws the doors wide open.

Not to be a wet blanket...

[SnoopJeDi]

...but Q4RT seems to have handicapped most of what makes the Doom 3 engine so impressive-looking to begin with. The reflection effects sure are nice, but it's a long way from making anything comparable to modern methods.

Sure is interesting, all the same.

Wow, real time -- glad I left that business

[dada21]

I was a founder of Deep Productions, one of the Chicago's first rendering farms about 15 years ago. I recall having dozens of Pentium 60s (Were they called Pentium Pros back then?) with 512MB of RAM (if I remember correctly) running a variety of rendering programs (usually 3D Studio, but others based on clients needs). IIRC, a single raytraced frame took about 20 minutes. 2 dozen machines churning full speed were able to render approximately 60 fields per hour, or 1 second of animation in an hour.

I exited that market and Deep eventually moved out of that field entirely, but looking back, I can't believe we made the money that we made at the time. Now that ray tracing is getting closer to real time, it gives me a few minutes pause to realize how much technology has changed in ways that the AVERAGE consumer has no understanding of -- and doesn't need to. In the end, I'm glad that so many entrepreneurs take risks so that consumers needs (and yes, entertainment for some is a need) and wants are fulfilled, without those consumers even knowing the process necessary to get there.

Handhelds first?

[Floritard]

if a certain configuration of hardware can render 1280x720 images at 30 frames per second, then that same hardware will be able to push 563 FPS at a resolution of 256x192 (which happens to be what the DS has). So why not make a handheld that can do real-time raytracing? Seems it would be easier to do. And that's a pretty good selling point to boast "better than PS3/360 graphics in the palm of your hand."

And to the above posts bemoaning the focus on graphics over gameplay, remember if they get a good real-time raytracing system in place then that frees the dev team up quite a bit. No longer having to work so hard on faking proper lighting, they can then focus on the more important things like gameplay/AI/physics.

Re:Handhelds first?

[smash]

So why not make a handheld that can do real-time raytracing? Seems it would be easier to do. And that's a pretty good selling point to boast "better than PS3/360 graphics in the palm of your hand."

It's just not worth it.

These days, games are often ported from platform to platform with fairly portable code (ie, written in C with platform specific low level stuff in ASM if required).

The second you put a raytracing platform out, every conventional raster graphics engine on the market becomes extremely difficult to port to it. It's all well and good being able to boast, but if you have no software to back up the claims, then it's a waste of time.

Is it still relevant?

[ggambett]

I wonder if this is still relevant.

Don't get me wrong, I love raytracers, but what once was their exclusive domain (reflections, shadows,...) has been done in a "fake" but very convincing way since the few latest generations of 3D video cards. What's left? True refraction? True curved surfaces? Is it that important? I tend to side with the "give me gameplay" crowd here.

Realtime caustics and global illumination, on the other hand...

Re:Not the shiny new hammer

[Anonymous Coward]

As an interesting sidenote to all of this, in 1993 I attended an Amiga fair in southern Sweden, where I saw a game demoed that utilized hybrid scanline rendering with certain "raytracing tricks", in realtime, to achieve what was then considered very life-like imagery. This ran in about 15-20 fps at peak, 320x256 resolution, on an Amiga 2000 with a 50mhz 68030/68882 accelerator board. Very impressive considering how early in time it was. The game also employed certain weak physics; you could pick up items and do anything with them; throw them, drop them, look inside of them; even redecorate the demo scene (which was a eerie lit house). The game at that point was titled Haunted, but unfortunately it never saw the day of light.

Here's the reason its not here now...

[tgd]

I remember fifteen years ago doing VR research work and people joking about real-time raytracing for games and VR. Computers are massively faster now than they were then. Why aren't we doing it at this point?

Resolutions have gone up enormously. Polygon count has gone up enormously. If we talk the sort of quality scenes we were rendering in 1993, it was only a few more years before it was possible to do them real-time... but at that point models were 10x more complicated and you weren't rendering for 320x240, you were looking at 640x480. Now we're doing millions of polygons at HD resolutions.

As long as people want more polygons, more texture detail, and higher resolutions, realtime raytracing will never be a production reality. Better hardware, faster CPUs, etc are all consumed quickly to handle richer environments and then suddenly there isn't overhead for raytracing anymore.

Ya I haven't really seen many benefits

[Sycraft-fu]

I don't care at all how the video card decides something needs to be rendered, so long as the results look good. I'm not concerned with the "correctness" of the calculations, only the results. I'd be all for a raytracing card if they found a way to make that work faster with less silicon than the existing rasterization systems. However, it seems we've really done a pretty good job of figuring out what can be quickly accelerated in silicon.

I'd much rather have good, fast, fake stuff than something that is done "right". As an example I actually generally like the graphics in UT2004 better than Doom 3. Despite Doom having a more "correct" lighting engine (all light comes from a source in game, there's no magic global lights) I find that the illusion breaks down too easy. Shadows are too hard, textures get too unrealistic when you get next to them (even in ultra mode) and so on. Now a lot of what UT2004 does to fight that is "faking" it. For example the whole detail texture thing. You get close enough to something, it fades in another texture layer over top that adds grit, imperfections, etc to what you are looking at. While that's "faked" it looks damn good and helps keep the illusion.

So I'm with you on the "give me gameplay". If they can make hardware that does raytracing as fast or faster than what we have and if it looks as good or better, great, I'm all for that. However I'm not at all interested in something that ends up being worse visually, either because it is slower or less detailed or whatever, just in the name of doing it more "correct".

Re:Not the shiny new hammer

[DamnStupidElf]

Raytracing has no advantage over rasterizing for opaque surfaces. Rasterizers are faster there, since their performance is not tied directly to the screen resolution. The advantages lie in refraction/reflection/shadows/translucency, which are painful to implement with rasterizers.

Actually, there's a big advantage. Raytracing is O(log n), but rasterization is O(n). OpenRT's demo of a 350 million triangle model of a Boeing rendered in real time on a single PC (without GPU support) is a good example. The entire model doesn't even fit in memory, so visible surfaces are cached. The result is still realtime (although only a few FPS) with incredible detail. Go slashdot the server and watch the movie. Modern raster based cards can only render that many triangles in a whole second with all their fancy hardware, if they're lucky.

Re:Raytracing is "embarassingly" parallel

[Guspaz]

Incorrect. They typically support alternate-frame rendering (each card does every other frame) for games that are problematic, but the best performance is to be had with tile-based rendering. This is where the SLI setup splits the scene up into a number of tiles, and then the two cards render them all, splitting the load so that each card is working as hard as it can. This is effectively splitting on the pixel level, but in a bit larger chunks. I'm sure that's because whatever overhead is involved probably increases the smaller the tiles get.

I think what he meant is

[Sycraft-fu]

"Where are we on the scale."

People sometimes get a little too giddy talking about Big O notation. Yes, something that scales logarithmicly rather than linearly will eventually be faster, but it kinda depends on where you are now if that will happen any time soon and thus is worth worrying about. To use arbitrary units, suppose at an 'n' of 1000 is the intersection point between the line for rasterization and the curve for ray tracing. So when we pass 1000, it starts to be a case that ray tracing is more worthwhile. Now suppose that current generation of graphics is 100, and it grows at a rate of 2 per year. Ya... Ok, not going to be worrying about that any time soon.

I think that was his point is that just saying "But it's O(log n)!" doesn't mean it is necessarily better at this point.

Also there is the silicon problem to be considered. We don't do our graphics on general purpose processors, we do them on highly specialized DSPs that actually have only recently gained turning completeness (and aren't very good at it, they are really slow at branching among other things). The graphics we see today are possible only because we can make a special purpose processor that can accelerate them very efficiently. Can the same be done for raytracing? I don't know. I mean I'm sure it is possible to an extent, especially since it is a very parallel problem, but that doesn't mean that we will be able to as efficiently accelerate it.

So while it is appreciated that at some point, on equal general purpose hardware, ray tracing is more efficient that isn't the question. The question is What is that point (and how soon will we reach it) and does that carry over to the special purpose graphics hardware?

But is it needed?

[nmg196]

In one of my lectures at university while studying Computer Science, the lecturer said:

People look at the TV and say things like "there's nothing on", "this is rubbish", "this film is so predictable", "surely not an ad break already". They don't often say, "I wish this TV had more pixels and a higher audio sampling rate".

Sometimes I think he's right. While I can see the merits of high definition and DTS, I've also seen plenty of films that seem to rely entirely on CGI and pretty graphics but have a weak plot (and plenty of games too for that matter). I hope this isn't going to make the developers spend even more time making textures, models and scenes just because you can see them so clearly.

Raytracing hardware is what's really needed...

[argent]

The kind of hardware needed to run raytracing really fast is well understood, and it doesn't really look like today's GPUs or like intel's CPUs, though even today you can get better results if you take advantage of the GPU as well. If ATI or nVidia doesn't come up with a hardware raytracing GPU someone else will. It's a pity that Intel doesn't seem to be interested in working on that angle.

Here's an article I've dug out of the Wayback machine and cleaned up, Raytracing vs Rasterization. Phillip Slusallek's home page is here, and you can follow that to SaarCOR and OpenRT. They built a prototype RPU (R for raytracing) that at 66 MHz was comparable in performance to a 2.6 GHz P4. The video is pretty impressive, considering how slow the hardware is.