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Intel Shows Off Quake Wars, Ray Traced
An anonymous reader writes "At the Research@Intel Day 2008, Intel showed a ray-traced version of Enemy Territory: Quake Wars. Compared to the original game, a water with reflections and refractions and a physically correct glass shader were added. Also, a camera portal with up to 200 recursions to itself has been demonstrated. To show off this ongoing research in the topic of real-time ray tracing, a four-socket system with quad cores has been used that allowed rendering the enhanced visual effects in 1280x720 at 14-29 fps. Just two years before, early versions of Quake 4: Ray Traced ran only at 256x256 with 17 fps. Even though Intel's upcoming Larrabee will be primarily a rasterizer, the capabilities for also doing ray tracing on it should deliver interesting opportunities."
I see two things here:
1. It runs on 4 x quad core. Which is about just 4X the CPU power a normal user could have right now. A 4X speed improvement isn't probably that far away. They may be hoping to reach a point where a dedicated video card is no longer needed. With the required performance level being so near, adding some extra support to the CPU may be enough.
2. Raytracing scales differently than methods currently used in games. With raytracing, increasing resolution is what adds the processing time, while adding detail is very cheap. Which I'm guessing means that as soon as you get raytracing going in real time at a decent resolution, adding extra quality is cheap. This would radically change the current situation, and possibly drastically bump the quality level.
3. Raytracing implements effects like shadows and transparency in a straightforward manner, which should make it easier to code. Game developers should like that. Also, in my understanding, raytracing also doesn't need to decompose things like spheres into lots of triangles, so the engine can test a ray's collision with a sphere directly. If you can specify parts of a scene as objects like spheres, toruses and such, it'd result in much finer detail.
What I think Intel is trying to do here to ATI/AMD and nVidia is the same thing fast CPUs did to soundcards. There's no longer a real need to have specialized hardware to play MIDI or add effects to sounds, since the CPU is quite capable of doing it itself. In fact, IIRC, Creative had to *blackmail* John Carmack into supporting EAX, because he could implement the same effects faster using the CPU.
Ray tracing mimicks how real world works.
Raytracing doesn't mimic how real world works. In fact it does exactly the opposite of what happens in real world. In real world you have bazillions of light particles, doubling also as waves, shoot out of many area light sources and bounce/be absorbed by objects around them.
Whatever photons end up hitting your retina, is what you see.
Raytracing instead shoots a ray out of your (virtual) retina straight forward to the scene and may refract/reflect off objects, until it's "absorbed" (means, hits a surface where refraction/reflection isn't calculated).
Rendering a single frame of 3D as it is in the "real world" (with just a fraction of the rays) would mean days on even the fastest hardware out there.
What raytracing gives you is sharp reflections, refractions and shadows, while introducing a bunch of other limitations on the rendering that rasterization doesn't have. It also can't do soft shadows, reflections, refractions, efficiently, nor subsurface scattering, or radiosity.
Best models for rendering in the future will likely be hybrid models similar to what is now used in professional renderers by movie studios. But then again, it's a game, who cares about mathematicaly accurate reflections, when you can fake it close enough with reflection/refraction maps in a fraction of the processing time.
A reflection on a doorknob and shadows are already quite easily achievable by current raster-based techniques. The former with dynamic cube-map FBO/PBO reflections (not perfectly accurate reflections, but given the size of a doorknob, more than acceptable). For the latter, per-fragment shadows (maps and volumes) have been around for quite some time (granted, in certain extremely high detail scenes ray tracing shadows might be faster).
.. Not sure that was entirely on-topic, but there's my tuppence on the near future adoption of ray tracing. Of course eventually everything will be done with unbiased rendering (basically just firing photons around and making them behave just like real photons would, see Maxwell Render. Currently, still extremely time consuming)
The biggest immediately noticeable pros of ray tracing from what I've seen are reflections in arbitrarily complex geometry (current generation raster shadows are only viable for planar and some spherical reflections, unless there's a technique I'm not aware of). This, however isn't a good enough reason to switch to a purely ray traced paradigm IMO.
From a gameplay perspective it all seems a bit niche, but I'm sure there's someone out there with an idea that could make use of it. I just don't see FPS du jour picking it up any time soon.
Having said that, ray tracing may be a good utility to use alongside rastering techniques for things like sub-surface scattering or ambient occlusion.