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Do You Think Ray-Tracing Is The Future?

Posted: Thu May 22, 2008 5:25 pm
by NeRve
Just as Pixel/Vertex Shader revolutionized graphics in the late 90's - do you think Ray-Tracing will do the same for the 00's and 10's?

Re: Do You Think Ray-Tracing Is The Future?

Posted: Thu May 22, 2008 5:41 pm
by UberGerbil
In case you haven't noticed, the 00's are almost over.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Thu May 22, 2008 7:27 pm
by mortifiedPenguin
While I think that ray-tracing will bring good stuff to the table it isn't the be all and end all of graphics. There are still a few things ray tracing is inefficient at doing that could be done with the same quality using rasterization. So I thing that a hybrid approach is the most likely solution for efficiency balancing.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Thu May 22, 2008 8:09 pm
by NeRve
mortifiedPenguin wrote:
While I think that ray-tracing will bring good stuff to the table it isn't the be all and end all of graphics. There are still a few things ray tracing is inefficient at doing that could be done with the same quality using rasterization. So I thing that a hybrid approach is the most likely solution for efficiency balancing.


Also from what I understand Raytracing requires a complete overhaul of all current GPU architectures because they are all based on Rasterizing (all current gens down to the old Radeon 7000 and TNT2 cards.)

Re: Do You Think Ray-Tracing Is The Future?

Posted: Thu May 22, 2008 8:09 pm
by BoBzeBuilder
I'm still not sure what ray-tracing does. Better lighting? I looked at some screen shots and they didn't wow me.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Thu May 22, 2008 8:26 pm
by mortifiedPenguin
NeRve wrote:
Also from what I understand Raytracing requires a complete overhaul of all current GPU architectures because they are all based on Rasterizing (all current gens down to the old Radeon 7000 and TNT2 cards.)

This is true, although I believe there are some efforts to run ray-tracing on GPGPU systems. Wouldn't be quite as fast as a "pure" ray-tracing system though. I figure such an architecture would have both dedicated ray-tracing and raster components with some sort of interconnect and a third processor to combine calculations into the final image.

BoBzeBuilder wrote:
I'm still not sure what ray-tracing does. Better lighting? I looked at some screen shots and they didn't wow me.

Not necessarily "better lighting" but a more accurate way of calculating lighting as well as things like refraction and reflection. Essentially, a ray-tracer shoots out rays of "light" and calculates their exact bounces as they hit objects and every time it bounces it would change the color/intensity/hue of the pixel that it hits. Makes for some pretty accurate lighting (in terms of physical correctness) if there are enough rays being cast from the light source.

edit: A good example of what ray-tracing can do.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Thu May 22, 2008 9:11 pm
by NeRve
mortifiedPenguin wrote:
NeRve wrote:
Also from what I understand Raytracing requires a complete overhaul of all current GPU architectures because they are all based on Rasterizing (all current gens down to the old Radeon 7000 and TNT2 cards.)

This is true, although I believe there are some efforts to run ray-tracing on GPGPU systems. Wouldn't be quite as fast as a "pure" ray-tracing system though. I figure such an architecture would have both dedicated ray-tracing and raster components with some sort of interconnect and a third processor to combine calculations into the final image.

BoBzeBuilder wrote:
I'm still not sure what ray-tracing does. Better lighting? I looked at some screen shots and they didn't wow me.

Not necessarily "better lighting" but a more accurate way of calculating lighting as well as things like refraction and reflection. Essentially, a ray-tracer shoots out rays of "light" and calculates their exact bounces as they hit objects and every time it bounces it would change the color/intensity/hue of the pixel that it hits. Makes for some pretty accurate lighting (in terms of physical correctness) if there are enough rays being cast from the light source.

edit: A good example of what ray-tracing can do.


That picture reminds me of the XNA Graphics Demos that Microsoft showed off a few years ago (not the recent ones, but old ones with the morphing animal, cigarette butt, etc...) Whatever happened to them I wonder? Anyways - I'm pretty sure current Rasterizing Tech can do that image, however it probably wouldn't be as efficient (with tons of unnecessary hardware overhead) as a pure Raytracer hardware...

Re: Do You Think Ray-Tracing Is The Future?

Posted: Thu May 22, 2008 9:14 pm
by UberGerbil
We've had discussions of this in the past -- you can search for them. Ray tracing has its pluses and minuses:
+ You get reflections, shadows, translucency "for free" (not exactly, but there's much less delta than adding the same features to rasterizing)
+ Computational workload doesn't increase with scene complexity (but scene complexity increases memory pressure).
+ It scales perfectly with computing resources, so you can keep throwing transistors at the problem as Moore's Law makes them available to you
- The computation workload increases with screen resolution. Twice the pixels, twice the work.
- The entire framebuffer has to be recomputed for any change of POV, no matter how trivial (there are some hacks to mitigate this, but they're hacks)

So we have one trend working in ray-tracing's favor (ever-increasing transistors and parallelism) and one trend working against it (ever-increasing screen resolution). The former is increasing faster than the latter, but there's still a lot of hurdles to cross. As a kind of example, here's your a wild-ass back-back-of-the-envelope computation:
1080p HD resolution is ~2MP. Obviously we'd like to aim higher since 2560x1600 displays are available today and QuadHD is looming, but 1080 is a sweet spot (especially if you're talking about consoles). At 60 fps, that's 120MP that have to be recalculated every second (remember, you have to recalculate the entire frame). Given that workload, a 4GHz processor gets all of 32 cycles to spend on each pixel. Clearly, that's not enough -- cache misses will blow up your throughput, and even if you can keep the entire scene in L2 (or get perfect prefetch) you're going to have trouble calculating much of anything in 32 cycles. So you have to throw more processors at the problem. How many? Well, that's the interesting tradeoff that Intel and nVidia and AMD are looking at. You can have more processors running slower, or fewer running faster, and you can trade off processors vs cache when spending your transistor budget. Not enough processors, and you'll be running at some slower frame rate; not enough cache so your scene spills out into main memory, and your frame rate crashes. Too much scene complexity (so again it spills out of cache) and your frame rate crashes.

This is why ray-tracing has been used for static scenes (or run offline, as Pixar does, to produce frame by frame in non-real time) and why in interactive graphics it is mostly used in a hybrid application, where it is employed just for reflections and other things for which it is particularly well-suited. (Scene complexity and its memory issues was a huge deal for Pixar when doing "Cars" -- they only had to fit the scene into memory, not cache, since they were rendering offline, but they still had issues with having enough memory to deal with scene complexity so they took a hybrid approach as well. See this PPT for an interesting discussion of this).
mortifiedPenguin wrote:
Essentially, a ray-tracer shoots out rays of "light" and calculates their exact bounces as they hit objects and every time it bounces it would change the color/intensity/hue of the pixel that it hits.
To be clear, it traces the light "backwards" from the eye (or, more exactly, the viewport representing the screen) into the scene to see where that light came from. Since each pixel on the screen represents one potential ray, by following it backward to a light source you can accumulate all the effects of reflections, translucency, and opacity of the materials in the scene it might hit along the way.

There are several introductions to ray-tracing (real-time and otherwise) around on the net; the recent one at Coding Horror isn't a bad place to start. Or, if you're more of a hands-on learner (or coder), see what you can find at OpenRT

Re: Do You Think Ray-Tracing Is The Future?

Posted: Fri May 23, 2008 1:26 am
by just brew it!
Ray tracing isn't revolutionary; the concept has been around for a very long time. What has caused a revival of interest in the technology lately is the fact that computational horsepower is finally getting to the point where we can start talking about the possibility of doing real-time ray tracing on reasonably priced desktop hardware. I think it is still a few years away from being practical though; it is simply too computationally intensive.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Fri May 23, 2008 6:12 am
by Meadows
UberGerbil wrote:
In case you haven't noticed, the 00's are almost over.

Much like the late nineties were, in the OP's line. I see consistency.

There are some things ray tracing can do, and some things that need to be worked out or where you need rasterized graphics. A very good example is reflection itself. Not all surfaces are perfectly reflective, which means over-using it on any surface would create an unrealistic ray-traced image with a worse impression than what the old ways (old in practical terms) could have given. I won't be a believer until I see it work, but I'm pretty sure the big dogs are working hard to make it happen.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Fri May 23, 2008 6:30 am
by Jigar
Meadows wrote:
I won't be a believer until I see it work, but I'm pretty sure the big dogs are working hard to make it happen.


X2, but i am really impressed with the image quality (link which mortifiedPenguin posted).

Re: Do You Think Ray-Tracing Is The Future?

Posted: Fri May 23, 2008 7:08 am
by just brew it!
Meadows wrote:
A very good example is reflection itself. Not all surfaces are perfectly reflective, which means over-using it on any surface would create an unrealistic ray-traced image with a worse impression than what the old ways (old in practical terms) could have given.

Only a very simplistic ray tracing algorithm would treat a surface as 100% reflective. Control of what colors are reflected (and how much) would of course be necessary. Surface normals can also be applied so that the surface is not perfectly smooth...

Re: Do You Think Ray-Tracing Is The Future?

Posted: Fri May 23, 2008 7:33 am
by liquidsquid
The point that needs to be made: Why? Will games/software truly benefit? As it is now, it seems the prettier the game/OS, the lousier the game/OS plays/is. All we need now is PCs that can render beautiful, stinky games. "Gee, look at how these Christmas Tree Ornaments sparkle! OMFG, who shot my head off!" or Look, my OS is prettier than yours, but I can barely run applications on it since it eats all of my GPU resources and memory!

To be honest I do not see how a card that can ray-trace has any real use on the computer other than a nice g-wiz. I would much rather have time spent on a more common-place physics accelerator to have interactive environments. Now that to me makes for a positive gaming experience. Besides, with most games I play, things are going by so fast, all you care about looking at it where the enemy is, and how to get 'em. Not that refractions through their blood plops are accurate.

-LS

Re: Do You Think Ray-Tracing Is The Future?

Posted: Fri May 23, 2008 1:43 pm
by UberGerbil
Meadows wrote:
Not all surfaces are perfectly reflective, which means over-using it on any surface would create an unrealistic ray-traced image with a worse impression than what the old ways (old in practical terms) could have given.
As JBI says, this has been a solved problem for over 20 years, which is why all the ray-traced images you can find (there are lots on the net, just look) don't make everything look like they're made out of liquid metal (unless that's the effect they're going for, in which case it's much easier to achieve than with rasterized graphics).
liquidsquid wrote:
The point that needs to be made: Why? Will games/software truly benefit? As it is now, it seems the prettier the game/OS, the lousier the game/OS plays/is. All we need now is PCs that can render beautiful, stinky games. "Gee, look at how these Christmas Tree Ornaments sparkle! OMFG, who shot my head off!" or Look, my OS is prettier than yours, but I can barely run applications on it since it eats all of my GPU resources and memory!
Quality of the game and quality of the graphics are (or should be) largely orthogonal issues. Look at Hollywood. You can have crappy movies full of gee-whiz special effects, and wonderful films that use nothing more than a single camera. But does it make any sense to say "Nobody can use any special effects in a movie because every movie that uses them is crap"? From what I've seen. the movies that manage to have fantastic effects and a fantastic story become true classics. "Hey, Steven Spielberg, you only get to use a black and white camera to make sure you focus on a the story!" What if somebody told Lucas he couldn't do the original Star Wars because a movie with lots of special effects is certain to be "stinky"?
To be honest I do not see how a card that can ray-trace has any real use on the computer other than a nice g-wiz. I would much rather have time spent on a more common-place physics accelerator to have interactive environments. Now that to me makes for a positive gaming experience. Besides, with most games I play, things are going by so fast, all you care about looking at it where the enemy is, and how to get 'em. Not that refractions through their blood plops are accurate.
These aren't necessarily conflicting goals. Much of the GPU development that would be necessary for real time ray tracing -- lots of parallel floating point execution units -- are exactly what you need to do physics. From the standpoint of the math that needs to be done, there's very little difference between projecting a light ray through space and projecting an object like a bullet. Whether it's your railgun or a light beam, you want to know where it goes and what it hits. The scatter of light off a diffuse surface is similar to the scatter of debris from an explosion. And so on. Something like Larabee, or it's successor, should be an awesome physics accelerator even if it never pans out for ray-traced graphics.

And sure, if all you're doing is playing twitch games there's a point where added visual effects detracts from the gameplay, or at least is just more visual clutter you ignore. But those sorts of games aren't going to exploit this much, and if they do they'll give you the option to turn it off. I can imagine certain ways it could be interesting even in a twitch shooter, though -- a fight in a hall of mirrors, catching a glimpse of your enemy reflected in the surface of the water as he tries to sneak under a bridge, etc. And it would be interesting to see what Valve might do with raytracing in a future sequel to Portal -- bouncing lasers off mirrors to trigger things, etc. Or what about a game where you occasionally obtain X-Ray vision?

I don't want to sound like I'm beating the drum for ray tracing -- for technical reasons I'm actually pretty dubious we'll see it catch on in any significant way (beyond some hybrid uses to dress up the visuals in conventional rasterizers) in the next five years. (It's pretty notable that even Pixar doesn't purely ray-trace, but uses a hybrid approach, even when they can employ as much computing horsepower as they need and have no requirement to work in realtime). But I don't see any reason to dismiss it out of hand just because some developers might misuse it like any new toy, or because we don't see how it might enhance existing games.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Fri May 23, 2008 1:46 pm
by Meadows
just brew it! wrote:
Meadows wrote:
A very good example is reflection itself. Not all surfaces are perfectly reflective, which means over-using it on any surface would create an unrealistic ray-traced image with a worse impression than what the old ways (old in practical terms) could have given.

Only a very simplistic ray tracing algorithm would treat a surface as 100% reflective. Control of what colors are reflected (and how much) would of course be necessary. Surface normals can also be applied so that the surface is not perfectly smooth...

I'm more interested in whether it can model objects which reflect the world blurred, that is, have flawed reflection as opposed to flawless.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Fri May 23, 2008 2:09 pm
by Flying Fox
Wait, I thought PS/VS is 00's tech?

Re: Do You Think Ray-Tracing Is The Future?

Posted: Fri May 23, 2008 2:25 pm
by mortifiedPenguin
Meadows wrote:
I'm more interested in whether it can model objects which reflect the world blurred, that is, have flawed reflection as opposed to flawless.
Can it model blurs? Yes, but it isn't terribly efficient. It would essentially be the projection of an identical or nearly identical ray onto a pixel offset of the "real" location of where it would be in a pure reflective object and blended with the color of the ray/pixel already there. It gets pretty computationally expensive at that point though, since we'll need to shoot out more rays to get the blending properly or we get some aliasing artifacts. That is actually one of the weak points of ray-tracing, when things are blended since we need more samples and more samples means more computation time. This would be a good example of where the hybrid approach makes sense, trace the reflection for accurate positioning/color then blur it using raster techniques.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Fri May 23, 2008 2:41 pm
by UberGerbil
Meadows wrote:
I'm more interested in whether it can model objects which reflect the world blurred, that is, have flawed reflection as opposed to flawless.
Of course (but it's more expensive). The issue is not just blurred reflection; it's also refraction. In fact the key to doing realistic-looking flesh is to do some internal refraction (subsurface scattering (PDF -- see images at the end) -- some light penetrates the skin and reflects out from underlying flesh/blood, which is also what gives the finest marble its lustre) as well as reflections from sweat/oils on the surface. (Here's a small PDF showing another example). Interestingly, many of the medical imaging techniques (CAT, MRI) use the same techniques -- they just are tracing back real rays, not imaginary ones. In fact, one of the origins of raytracing was a team of physicists ooking at working backwards to trace the path of subatomic particles, and when they showed off what they were doing to computer graphics professionals the CG guys said "You've solved the Hidden Surface Problem!" And the physicists said "What's the Hidden Surface Problem?"

Of course that's getting a bit far afield from what is needed in fast-twitch games. Another form of "blurring" may be more interesting there: motion (vector) blur.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Sun May 25, 2008 7:58 am
by bogbox
yes, but over 5-10 years or so. I read a article about this ,and amused me ,3 ps3 on a single static image , a bit much for our days .for this to have success i think more people will have to buy very expensive hardware , not going to happen better buy a ps3 or ps4 (in 5 years) .the pc is dying , laptops with IGP(dx 10 ?, what a joke :lol: ) are the future , and for games xbox or play station or wii.(with ray tracing )
Ray tracing will be the future because intel and nvidia will invest in it . microsoft is going to lunch dx11 with ray tracing so .. it's clear. :D

Re: Do You Think Ray-Tracing Is The Future?

Posted: Sun May 25, 2008 10:14 am
by Meadows
bogbox wrote:
blablabla (...) the pc is dying (...) laptops with IGP are the future (...) blablabla

How can the PC die, if laptops are the future? A laptop is a PC.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Sun May 25, 2008 4:15 pm
by bogbox
Meadows wrote:
bogbox wrote:
blablabla (...) the pc is dying (...) laptops with IGP are the future (...) blablabla

How can the PC die, if laptops are the future? A laptop is a PC.

good point !what about a ps3 with mouse and keyboad and a emulated xp is a PC too? yep:D :lol:
my bad ! labtops are not for games ,just ask a igp from intel :lol:

Re: Do You Think Ray-Tracing Is The Future?

Posted: Sun May 25, 2008 4:36 pm
by Meadows
bogbox wrote:
good point !what about a ps3 with mouse and keyboad and a emulated xp is a PC too? yep:D :lol:
my bad ! labtops are not for games ,just ask a igp from intel :lol:

In the broad sense of the phrase, a PS3 qualifies as a PC as well, and you don't need to emulate Windows on it and you don't need a keyboard/mouse for that.
Laptops can be used for gaming and are very advantageous for LAN party travelling. "Ask" any discrete GPU from nVidia, to put it your way.
You continue to make moot points.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Mon May 26, 2008 5:48 am
by bogbox
Meadows wrote:
bogbox wrote:
good point !what about a ps3 with mouse and keyboad and a emulated xp is a PC too? yep:D :lol:
my bad ! labtops are not for games ,just ask a igp from intel :lol:

In the broad sense of the phrase, a PS3 qualifies as a PC as well, and you don't need to emulate Windows on it and you don't need a keyboard/mouse for that.
Laptops can be used for gaming and are very advantageous for LAN party travelling. "Ask" any discrete GPU from nVidia, to put it your way.
You continue to make moot points.

A ps3 is a pc , and the war PC vs consoles is over . long live Pc(S3) !and Mac is a PC too, so even my cell phone is a pc , or my watch,.....etc.
PC is in all , and all are PCs.
a $3000-$4000 laptop is good for gaming, but how many have a $3000(at least) laptops with SLI or high end graphic cards?
for wow or cs source , will be fine with intel extreme graphics (80% of the market use a integrated crap) , but rest of market ? max 15% use a 8700m or older go series so no well DX 9c, DX10 maybe in 2-3 years.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Mon May 26, 2008 6:54 am
by Fighterpilot
Gotta admit I saw some game called Metal Gear Solid something or other at an electronics store the other day running on a PS3.
The graphics were so crisp and colorful it was almost like watching an animated feature film...impressive.

Re: Do You Think Ray-Tracing Is The Future?

Posted: Thu Jun 19, 2008 11:27 am
by HurgyMcGurgyGurg
Really, the performance hit that Ray-Tracing has makes it in-effective to use for at least another ten years. Likely, we will start to see ray-tracing blending in as an added feature in future games for certain things, reflections etc. but it will not be the main rendering technology for awhile.