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Thread: The Most Amazing OpenGL Tech Demo In 64kb

  1. #61
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    Quote Originally Posted by RealNC View Post
    Wow. This article didn't mention the term "Demo Scene" even once. Not once!

    Really? Are you f...... serious, Phoronix?
    You are really asking that? Aren't you aware that Michael already clarified that for him quantity is better than quality?

  2. #62
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    Quote Originally Posted by Vim_User View Post
    You are really asking that? Aren't you aware that Michael already clarified that for him quantity is better than quality?
    Games that include gigabytes of textures and movies, don't always make better graphics. As JC stated, visuals are always an illusion. So even for gigatextures, the whole point is that detail comes from clever illusions to make whatever on the screen look real.

  3. #63
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    Yeah, like others have mentioned, it looks pretty nice, but ray(back)tracing (& similar techniques) are generally too expensive for real gaming (although numbers of 'hops' can vary depending on load and fps).

    While easy to implement, few hundreds LoC (not including render for scene and primitives),
    it still cant be used for realtime stuff because performance is several orders higher than what it would take to do the same thing via conventional Z-buffer (&similar).

    This is inherent flaw caused by the fact that whole scene has to be redrawn each frame (although I've seen experimental code which worked around this by cacheing ray objects and reusing stuff when possible).



    Please note that some 'glitches' these are caused by premature termination of rays.
    Last edited by tpruzina; 04-23-2014 at 04:34 PM.

  4. #64
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    Quote Originally Posted by b15hop View Post
    Games that include gigabytes of textures and movies, don't always make better graphics. As JC stated, visuals are always an illusion. So even for gigatextures, the whole point is that detail comes from clever illusions to make whatever on the screen look real.
    Yeah, huge textures in mipmaps, e.g. texture being stored in various resolutions which are used depending on framerate/relative distance from camera and object (actually it's more complicated than that).
    Game engines have barely evolved since 90's (notably quake3 engine), in fact most current engines are based on original quake engine (z-buffer for scene depth and various hacks like bump mapping to make it look real).

    For true quality, you gonna need physics simulation like raytracing, beam tracking and radiosity.
    Most of these can be seamlessly combined together, but they are computationally most expensive, since lighting must be computed per each frame.

    Most people would be amazed how difficult is it to render things like mirrors, difraction or believable shadows.

  5. #65
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    Quote Originally Posted by tpruzina View Post
    Yeah, like others have mentioned, it looks pretty nice, but ray(back)tracing (& similar techniques) are generally too expensive for real gaming (although numbers of 'hops' can vary depending on load and fps).

    While easy to implement, few hundreds LoC (not including render for scene and primitives),
    it still cant be used for realtime stuff because performance is several orders higher than what it would take to do the same thing via conventional Z-buffer (&similar).

    This is inherent flaw caused by the fact that whole scene has to be redrawn each frame (although I've seen experimental code which worked around this by cacheing ray objects and reusing stuff when possible).



    Please note that some 'glitches' these are caused by premature termination of rays.
    Notice the noise in the video? The grains are possibly due to the low level of traces per pixel. I'm guessing less than 200 per pixel. He's made it so that fast moving areas are more grainy than still images. Very smart move but it looks very grainy when lots of stuff is happening at once.

  6. #66
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    Quote Originally Posted by b15hop View Post
    .... The grains are possibly due to the low level of traces per pixel. I'm guessing less than 200 per pixel.
    Thats not how raytracing works, IRL it works like lightsource emits beams that reflect out of object and are catched by viewpoint (eye),
    in raytracing this is done reversely, viewer (viewpoint) sends out beams that reflects out of objects and if they manage to end up in lightsource, it then recursely illuminate objects.
    So "quality" is based on not only number of hops, but also number of rays in the scene.

  7. #67
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    bout forward and backward raytracing are viable methods, and even a mix is

    raytracing, realistically speaking, will probably become mainstream when i will be an old man, if then
    it's just too heavy (and you can do calculations on that, or just dl a optimized raytracer)
    also that they are games, not simulations
    and games don't need to be ultra realistic to be fun

    approximations... maybe, like course photon mapping

    funny, i remember an old game that used path tracing to shade the terrain
    i think (not sure) that sc2 does something like that for some details

  8. #68
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    Quote Originally Posted by gens View Post
    bout forward and backward raytracing are viable methods, and even a mix is

    raytracing, realistically speaking, will probably become mainstream when i will be an old man, if then
    it's just too heavy (and you can do calculations on that, or just dl a optimized raytracer)
    also that they are games, not simulations
    and games don't need to be ultra realistic to be fun

    approximations... maybe, like course photon mapping

    funny, i remember an old game that used path tracing to shade the terrain
    i think (not sure) that sc2 does something like that for some details
    That youtube demo that I posted was implemented on top of GTA4 if my memory serves my correctly.
    Raytracing is pretty standard in movie industry (pixar and co), when animated movie runs for day or two on few capable servers to produce 'realistic' lighting (shading).
    Demo though looks like 100 year old camera (which also had problem with optics not getting enough light beams to be projected onto film).

  9. #69
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    Quote Originally Posted by gens View Post
    bout forward and backward raytracing are viable methods, and even a mix is

    raytracing, realistically speaking, will probably become mainstream when i will be an old man, if then
    it's just too heavy (and you can do calculations on that, or just dl a optimized raytracer)
    also that they are games, not simulations
    and games don't need to be ultra realistic to be fun

    approximations... maybe, like course photon mapping

    funny, i remember an old game that used path tracing to shade the terrain
    i think (not sure) that sc2 does something like that for some details
    Yes I understand that as a programmer. I don't worry too much about technicalities because at the end of the day it's more important to just look good and play well... For us as a user, the user doesn't care about technicalities of the engine. To them, the impression of reality is based on how awesome it looks rather than how many rays are processed per frame. They don't care how much number crunching is going on in the background just to render a crate on the floor.... Sometimes taking shortcuts to give the same effect makes everyone just as happy.

    On topic though, I'm still impressed with this demo and any demo that pushes the bounds of the GPU. The best part of 64k demos is that they're doing the whole "MORE for LESS". The idea being that you don't need exabytes of data to render a simple scene... Remember, the whole thing is all an illusion anyway. So if a hamster was powering that GPU and gave you real time (<5ms) shading of a carrot that made you want to eat the computer screen. If the carrot was so real that you now have an addiction to eating carrots. Yet the whole demo is 64k.... Then so be it. Bring on the carrots.

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