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Thread: raytracing vs rasterisation

  1. #1
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    Default raytracing vs rasterisation

    Just starting a thread to discuss some more on raytracing vs rasterisation, now that OpenCL is available in some places (no doubt that ray tracers will benefit from OpenCL - quite a few were done using CUDA I hear).

    So.....do people think ray tracing will replace traditional rasterisation (such as with OpenGL)?

    I'm of the opinion: no, won't replace it. An approach combining the two would be more likely - ray tracing is very good at some things (lighting, shadow calculation, and some others that I can't think of at the moment), but is traditionally slower with soft shadows, and requires quite a bit of computational power (not very useful for mobile devices). I'm also not sure how well ray tracing handles particle systems.

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    not replace, work with? i hope so. If history serves as any indicator, computing power will increase.

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    I believe ray tracing has the potential to replace OpenGL in the near future (3 years) for rendering 3D scenes, games and such. But OpenGL will remain for desktop compositing. That would be nice to have because dedicated GPU's on CPU's would be capable and responsive enough. The money that you saved from not buying a graphics card could be spend on a faster CPU that will increase overall system performance and responsiveness even more, reduces the energy bill and gives longer batterylife and less heat on laptops, removing the need to extra cooling, prolongs batterylife even more...

    The future is full blown ray tracing, but we need a good implementation. I have been subsribed to Intels graphics research and read many papers about different aspects of ray tracing and everytime I sratch my head and think; what were thinking? It seems people with great inteligence but zero insightfulness are thrown at the problem and I think that I can do it at least 100 times better than every attempt that has been tried so far.

    If you look at SourceForge there are countless ray tracing renderers without any kind of vision whatsoever and the closest thing that comes to a vision is the closed source, triangle rendering OpenRT.

    Hybrid rendering is too complex to code, suffers from terrible synchronisation problems, can still only render triangles and only gets slower the mroe detailed the scene gets at zero benefit, except for some cool triangle cruved shadows... Sounds to me like a vision of the future that is totally not thought threw...

  4. #4
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    Hybridised rendering techniques definitely suffer from a lot of problems, that much is sure, and it's not at all clear that it would be worthwhile trying to overcome them. I did have interesting thoughts on replacing triangle representation with something else, but otherwise keeping the current rendering pipelines, but that kind of thing belongs as uni research papers or something (not something I have the time to look into).
    The problems with ray tracing more or less comes down to raw computing power and memory limits, as far as I see it (I'll confess not having written a ray tracing engine myself - though I have written some physics ray-intersection stuff). So if enough computing power can be put together, and at reasonable power requirements, it might be feasible, but that still looks to be a (very) long way off.

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    Quote Originally Posted by mirv View Post
    I did have interesting thoughts on replacing triangle representation with something else, but otherwise keeping the current rendering pipelines, but that kind of thing belongs as uni research papers or something (not something I have the time to look into).
    Voxels?

    So if enough computing power can be put together, and at reasonable power requirements, it might be feasible, but that still looks to be a (very) long way off.
    Don't forget that raytracing scales really well. It takes 20 AMD 1800s to get playable framerates by replacing all effects in OpenGL 2.0 with ray tracing counterparts (OpenRT, "Quake 3 Ray Traced"). According to my own calculations based on Intel's roadmap we'll have that very power in 3 years. The latest Sun Sparcs are probably already capable of doing OpenRT at playable framerates (64 threads @ 2.6gHz)...

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    sure, computing power increases. But assuming that we don't have anything better to do with that power than to do ray-tracing is absurd.

    So in a few years, computers will finally be able to play Quake 3 with raytracing. Or play Crysis with traditional rendering. I wonder what'll look better.

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    Quote Originally Posted by V!NCENT View Post
    The latest Sun Sparcs are probably already capable of doing OpenRT at playable framerates (64 threads @ 2.6gHz)...
    why the hell are we using x86 cpu's anyways?!?! God damn we are linux users i say!

    i say!
    i say!

    we should use whatever we damn well want!



    On a side note. L33F3R predicts that ray tracing will become a big thing in the porn industry.

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    Quote Originally Posted by L33F3R View Post
    why the hell are we using x86 cpu's anyways?!?!
    Because we are cheap bastards who want CPU's with as high clock frequency as possible with the least cost?

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    Quote Originally Posted by L33F3R View Post
    why the hell are we using x86 cpu's anyways?!?!
    Solely because of Microsoft...
    PS: Single thread execution is the fastest and most efficient on Intel x86 CPU's.
    Last edited by V!NCENT; 10-07-2009 at 02:53 PM.

  10. #10
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    Quote Originally Posted by V!NCENT View Post
    Voxels?
    Not really voxels....

    With the trend to programmable pipelines, I can see software renderers making a comeback. That would allow more than simply triangles to be processed, and perhaps even more of a "description" of objects than object data (think svg for images).

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