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Add Another Core for Faster Graphics
Dzonatas writes "Need a reason for extra cores inside your box? How about faster graphics. Unlike traditional faster GPUs, raytraced graphics scale with extra cores. Brett Thomas writes in his article Parallel Worlds on Bit-Tech, 'But rather than working on that advancement, most of the commercial graphics industry has been intent on pushing raster-based graphics as far as they could go. Research has been slow in raytracing, whereas raster graphic research has continued to be milked for every approximate drop it closely resembles being worth. Of course, it is to be expected that current technology be pushed, and it was a bit of a pipe dream to think that the whole industry should redesign itself over raytracing.' A report by Intel about Ray Tracing shows that a single P4 3.2Ghz is capable of 100 million raysegs, which gives a comfortable 30fps. Intel further states 450 million raysegs is when it gets 'interesting.' Also, quad cores are dated to be available around the turn of the year. Would octacores bring us dual screen or separate right/left real-time raytraced 3D?"
There are already ray traced games. :O
http://graphics.cs.uni-sb.de/~morfiel/oasen/
F.A.N. released a real-time raytraced demo at breakpoint back in 2003. It does no more than 10 fps on my lowly 1GHz P3, but I'm sure it runs quite smooth on a nice modern CPU (though I don't think it's multithreaded).
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Take a look at the proceedings from any graphics conference in the last three or four years, and you will see several papers which involve ray-tracing on a GPU. Actually, not so many recently, because it's been done to death. The most impressive one I saw was at Eurographics in 2004 running non-linear ray tracing. As the rays advanced, their direction was adjusted based on the gravity of objects in the scene. The demo (rendered in realtime) showed a black hole moving in front of a stellar scene and all of the light effects this caused.
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Just found that game using raytracing - Quake 3: Raytraced./
http://graphics.cs.uni-sb.de/~sidapohl/egoshooter
Rumors are there's a q4 version on the way.
I wonder how much this research relates to Intel's renewed desire to become a graphics player.
If they're having trouble, for staffing or other reasons, producing good GPU designs, then it would be pretty clever of them to revolutionize the industry AND capitalize on their CPU strengths in a single move. More power to them, I say. (More power = about 120 watts, I'm guessing.)
I've been thinking about the same thing, but only with 1 core dedicated to the Operating System itself, without the drivers for the various peripherals. This way it should become a lot easier to make a crash free OS: when one core (the OS one) has a higher priority than the other(s) and the only code inside the core is some kind of busy loop checking if the other core is still working as planned. Perhaps of course its already been done by Sun/IBM/... and I'm busy reinventing the wheel.
Found this link a while ago: http://graphics.cs.uni-sb.de/SaarCOR/
Methinks it would be pretty cool when there's a 'graphics' card that could do standard raster-based graphics, raytracing and physics. Most of the calculations are the same anyway, so a general purpose processor that is very good in floating-point vector calculations would be necessary. The API's would be mostly implemented in the driver (OpenGL, OpenRT, etc.)
It's not just the sheer number of FP calculations that can be the problem. Once you get away from the first (or perhaps even second) level of rays, you end up losing coherence between neighbouring rays which causes memory page/cache thrashing. This is not a nice thing on a GPU.
Ray tracing also suffers terribly from "jaggies". Edges look bad because rays can just miss an object and cause really bad stepping on the edges of objects. To eliminate jaggies and do anti-aliasing, you need to do sub-pixel rendering with jitter (slight randomness) to produce an average value for the pixel. So you might have to trace 4 or more rays in a pixel for acceptable anti-aliasing. Effects like focal length, fog, bump mapping etc. cause things to get even more complex. Most pictures rendered with high quality on Blender, POVRay etc. would take minutes if not hours even on a fast / dual core processor.
The only way you'd get 30fps is if cut your ray trace depth to 1 or 2, used a couple of lights, cut the screen res down and forgot about fixing jaggies. It would look terrible. Oh and find time for all the other things that apps and games must do.
A ray-tracing problem can be solved simultaneously using a moment method that incorporates physical optics. I wrote my Master's thesis a long time ago that did precisely that for 2-dimensional situations. Of course, this required solving massive linear systems that, at the time I wrote it, took hours on a 433MHz Alpha to do a single frame, and it was written in FORTRAN77, but hey, we've come a long way since then :)
It's nice that people are working on ray traced games, but please note the following:
...
Oasen is based on "OpenRT" --- which is entirely proprietary, and is NOT open source. Their FAQ explains that clearly.
I'm sure that I'm not the only person annoyed at their use of "open" to mean "closed".
Time to look for an open-source raytracing engine designed for interative use
I am not an expert in OSes, I thought that the idle process just gave the CPU something to do while it waited for a working process (the idle just allowed the working to butt-in, whenever somethin came along).
Wouldn't creating a core just to do nothing be hardware bloat at its most obsurd?
Or am I showing my ignorance, just a bit too openly.
If this were really happening, what would you think?
Thats because a reflection creates another ray segment, and a refraction creates two.
Considering a non-reflective ray traced world at 800x600 needs 320,000 rays to be cast to calculate an image, so 9,600,000 at 30fps, the claim of 450 million ray segments makes sense... thats 45+ per pixel at 800x600, which is a lot of reflections. Usually you'd limit the number to a fairly low because 100 deep reflections don't add noticable detail, especially in motion. Thats a lot of room for both refractive and reflective objects to be in the scenes.
You probably wouldn't just use one ray per pixel. It is typical to fire a number of rays and then average the result. This is because rays diverge quite quickly after passing through the display port, and so you get quite an uneven image. There is a noticeable difference between 1 and 4 rays per pixel, and between 4 and 9. After 9, you start to get into diminishing returns, and beyond about 25 it becomes harder to spot the difference (note that it is common to use a square number of rays, since that makes it easy calculate where they should go).
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As for dynamic scenes, this is actually easier in many ways with a ray tracer. If you start with a scene graph API, you just need to send the changes each frame. How much changes in a typical game? Most of the scenery is fairly static. The characters move and deform slightly (you can often get away with a spacial transfer function, rather than a real change to the geometry in this case). With a traditional graphics pipeline, you still need to redraw every single polygon every frame. With a ray tracer, you can cache huge amounts of the scene (in terms of secondary rays; simply save the results of them as a texture and perform a lookup here for the next ray, and invalidate the texture when something moves between it and any of the light sources).
Ray tracers have been running in real time for a while (take a look at Utah), but not on cheap hardware. The hardware will catch up soon. Take a look at some of the designs from Microsoft Research; they have some very shiny FPGA-based logic which does 100% procedural graphics and is likely to show up in the XBox 3.
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I'll let the other posters comment on the wrongness of your idea that raytracing doesn't scale with scene complexity. There was a nice SciAm article about it, if you need more convincing. Instead, I'll talk about something in the article that the other posters didn't mention. Raster Processing may scale with scene somplexity, but creation doesn't. Raster graphics must be tweaked at creation to make an object look realistic while still rendering quickly. With ray tracing, you just create an object and forget about it. It just looks right without any tweaking.
What costs game designers more: hand tweaking every object, or you buying a better computer so you can ray trace their un-tweaked objects? Now guess which way 3D graphics are gonna go...
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There was a paper published a couple of years ago (at Eurographics?) about this. Each ray was independent, and would return a value at each intersection (i.e. you get the primary ray value quickly, and then refine it further with secondary, tertiary, etc ray data). When a ray was no longer lined up with a pixel, it was interrupted and terminated. This meant that you got a fairly low quality image while moving quickly, but a much better one when you let they rays run longer. I found it particularly interesting, since it completely removed the concept of a frame; each pixel was updated independently when a better approximation of its correct value was ready, giving a much better degradation.
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Shadows; they'd be Doom 3-like. Several games have full stencil shadows and that's just how raytraced ones would look: sharp and straight.
Sharp and straight shadows? Check out this example or this one or yet another. Granted, these scenes rendering times are measured in hours, not fractions of a second... but eventually games will be at that level of quality.
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I remember a talk from someone (John Carmack I think) saying something like raytracing is nice but overkill. Today's hardware maybe be able to handle realtime raytracers but no way near the quality you can get from current 3D engines.
Most special effects you see in current engines are approximation/hacks compared to what you can do with a raytracer but it's also way cheaper to compute.
It's the same kind of relationship than between texture maps vs procedural textures. Procedural textures are better for a rendering point of view, they scale better. But it's also lot harder to make a good quality texture and it requires a lot more power to render.