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Posted by metlslime on 2002/12/23 18:24:21 |
Talk about anything in here. If you've got something newsworthy, please submit it as news. If it seems borderline, submit it anyway and a mod will either approve it or move the post back to this thread.
News submissions: https://celephais.net/board/submit_news.php |
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Hell Yes
#14395 posted by necros on 2008/06/17 02:29:26
i WISH d3 had proper lightmap support. :\
if only to bake on ambient occlusion, ffs.
i'd be more impressed with realtime ambient occlusion, actually.......
Hmm
#14396 posted by megaman on 2008/06/17 02:42:51
texturing slower in raytracing? why? at first glance, i'd guess you just need a texture lookup for each ray.
The nice thing about raytracing is that there's basically no hacks involved, much unlike rasterizing where everything is one giant hack ;)
global illumination raytracing isn't really realtime yet, i think.
I Still Remember Playing Myst All Those Years Ago...
#14397 posted by mwh on 2008/06/17 03:19:50
... and thinking "when will this be real time?"
Though I guess original-Myst-level stuff has probably been possible in real time for a while now (though obv. I'm talking about ray tracing, not realMyst :)
There
#14398 posted by HeadThump on 2008/06/17 03:41:53
is at least one damn good reason to look forward to the development of raytracing, scalability:
http://www.flipcode.com/archives/Raytracing_Topics_Techniques-Part_1_Introduction.shtml
One document especially grabbed my attention. It's titled: "State-of-the-Art in Interactive Ray Tracing", and was written by Wald & Slusallek. I highly recommend this paper. Basically, it summarizes recent efforts to improve the speed of raytracing, and adds a couple of tricks too. But it starts with a list of benefits of raytracing over rasterization-based algorithms. And one of those benefits is that when you go to extremes, raytracing is actually faster than rasterizing. And they prove it: Imagine a huge scene, consisting of, say, 50 million triangles. Toss it at a recent GeForce with enough memory to store all those triangles, and write down the frame rate. It will be in the vicinity of 2-5. If it isn't, double the triangle count. Now, raytrace the same scene. These guys report 8 frames per second on a dual PIII/800. Make that a quad PIII/800 and the speed doubles. Raytracing scales linearly with processing power, but only logarithmically with scene complexity.
?
#14399 posted by necros on 2008/06/17 05:07:32
that... doesn't make sense. that means that with enough processing power, you could make a scene infinitely complex without any difference in performance...
I Interperted The Last
#14400 posted by HeadThump on 2008/06/17 05:48:33
sentence to mean that the ray tracing algorithms will yield a stable product where the problem of rendering is only proportional to the size of the data set that it is handling.
That Entire Series Is Fascinating
#14401 posted by HeadThump on 2008/06/17 05:50:12
One of the latter articles features an easy to fallow explanation of kd-trees.
Fallow, Follow
#14402 posted by HeadThump on 2008/06/17 05:51:16
in monkey phonetics I trust
Scalability My Ass
#14403 posted by gone on 2008/06/17 07:29:28
everyone knows raytracing performance is much less dependant on polycount, much more on resolution
so throw 1600x1200 at it and cry
Except Those Who Actually
#14404 posted by HeadThump on 2008/06/17 08:26:34
build ray tracers: Way to embarrass yourself, speeds:
http://www.flipcode.com/archives/Raytracing_Topics_Techniques-Part_4_Spatial_Subdivisions.shtml
The last scene from the previous article (the one with the sphere grid to show off the new refraction code) took almost 9 seconds to render on my pimpy 1.7Ghz Toshiba laptop with 1600x1200 screen (I know resolution has nothing to do with it, but I thought I would mention it anyway). And that's just for simple stuff. Later on we will add area lights, and to test the visibility of those, we will need lots of rays � for each pixel, that is.
Funny
#14405 posted by SleepwalkR on 2008/06/17 08:39:58
Because AFAIK, speeds is right: Every pixel adds one ray to be traced, so raytracing complexity is very much dependent on resolution. Can someone explain this?
Umm Necros
#14406 posted by bambuz on 2008/06/17 08:55:42
logarithmic means the time grows slower. It still goes to infinity when the polycount goes to infinity.
Think
#14407 posted by HeadThump on 2008/06/17 09:02:22
of the advantage in size and speed you obtain when you use vector graphics as opposed to bit map graphics in web apps. The advantage comes from the fact the image is a sheer calculation that scales perfectly with the resolution whereas the bit map is a an indexed means of storage.
The advantage of ray tracing is similar:
http://www.iss.rwth-aachen.de/Projekte/grace/raytracing.html
The results are based upon sheer calculation whereas rasterization relies on spans of texturized pixels. The advantages will be more apparent when mega units of polygons are rendered with surfaces represented by polies instead of textures.
Rather old, but still relevant:
http://graphics.cs.uiuc.edu/~jch/papers/rtqjs.pdf
BTW, I Think Both Bikker And Speeds
#14408 posted by HeadThump on 2008/06/17 09:14:14
are wrong, hence the first site I linked. It does have something to do with it, but that becomes less relevant with larger data streams.
One Last Thing
#14409 posted by HeadThump on 2008/06/17 09:37:37
before I crawl into bed, this is what Bikker has been up to of late:
http://igad.nhtv.nl/~bikker/
I Really Don't Get How You Get
#14410 posted by bambuz on 2008/06/17 09:45:36
smooth lighting with raytracing.
I mean if you trace from the eyes and not from the light sources, once you hit the first surface, your beam splits to a million different directions. And then again for the next bounce and then for the next. How much until the ray dies or goes to the sky?
It's a very hard problem and results in ugly and unphysical hacks that produce very stupid looking images.
Megaman
#14411 posted by BlackDog on 2008/06/17 10:02:45
Rasterisers texture very quickly because the inner loop is a good match for hardware. Triangles go through the pipeline and wind up on the screen as scanlines, basically two endpoints with some associated attributes (texcoords, vertex colour, etc). Texturing the scanline is just a matter of interpolating those attributes between their two known values, which is very fast. Cache coherency is also good, since two adjacent pixels will be located close in the same texture (mipmapping ensures this).
In comparison when you fire off a ray, the hardware has no idea how that pixel will need to be shaded.
Wii Port With Wiimote Aiming
#14412 posted by Spirit on 2008/06/17 11:04:23
Err, Yes,
#14413 posted by megaman on 2008/06/17 12:19:05
but that's a large part of raytracing optimisation, making things run in a way that you can use coherency between rays. And, yeah, as long as we don't have gpu like computing power for raytracing...
Ray Tracking
#14414 posted by Kinn on 2008/06/17 12:35:29
Now I ain't much good at the internets, like some of you whizzkids, but does all this technologistic hocus-pocus mean that dem computering games goan be mighty purdy?
Yeah Sure Will Pardner.
#14415 posted by Shambler on 2008/06/17 13:26:40
Gameplay'll still suck some dem balls tho.
#14416 posted by JneeraZ on 2008/06/17 15:09:58
"Gameplay'll still suck some dem balls tho."
Well, ray tracing doesn't really affect gameplay unless you're going to argue visibility of enemies in a unified lighting scheme or something.
RE #14412
#14417 posted by RickyT33 on 2008/06/17 15:59:32
Thats cool Spirit!! The screenshot is too dark tho....
Totally ruins everything in my life....
Go Ahead Beat A Dead Horse If You Will
#14418 posted by gone on 2008/06/17 18:31:16
but atm raytracing stands no chance for realtime rendering vs "raseterizing", cause the later been advanced by the whole software and hardware industy for the last 10+ years and its not stopping. I think Carmack ok Sweeney, said that, not my words really.
tere is a joke that goes "Ray tracing is the technology of the future and it always will be!"
and in the future we`ll have a nice blend both
but so far there is no reason to get any excited
#14419 posted by JneeraZ on 2008/06/17 18:44:38
It's nice to see research into other areas, that's all. It's not time wasted if something of value is learned - even if that something is that ray tracing isn't currently viable or what-have-you.
Pushing more and more triangles through the pipeline will likely reach a point of diminishing returns.
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