Chat Transcript: ATI's texture filtering algorithms

Discussion in 'Architecture and Products' started by cho, May 20, 2004.

  1. cho

    cho
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    http://www.ati.com/online/chat/
     
  2. NutSack

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    Interesting, looks like they dodged anonymouscoward's question a little bit when he asked the straight forward question of "is it the same". This will probably prove to be a more powerful event(the chat) that has happened than will fully be realized. Also, I was a little disappointed they wouldn't give a pending patent number. I have a strange feeling they haven't filed one yet and probably weren't going to until someone in pr said "That sounds like a good idea".

    Just my 2 cents...come on Matrox...
     
  3. bloodbob

    bloodbob Trollipop
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    LIE LIE LIE LIE

    Their is a conditional step in their algorithim it is neither mathematically linear nor is it A*X+B*(1-X) ( which is mathematically linear ).

    It is
    If X < Threshold return A;
    else X > 1-Threshold return B;
    else return A*([X-Threshold]/[ 1 - 2*Threshold] )+B*([1-X-Threshold]/[ 1 - 2*Threshold])

    Or something close to it.


    ATI claim their new technique is better then FULL Trilinear ( the best implementation of Trilinear of course is trilinear which nvidia has done in the past.

    Oh so now your saying it might not actually be better?
     
  4. BRiT

    BRiT (╯°□°)╯
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    To me it seems like their implementation is:
    A*Y+B*(1-Y), with Y=f(x) ... Where f(X) produces visual-equivalent of X.
     
  5. bloodbob

    bloodbob Trollipop
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    And if you subsitute f(x) for Y? then it won't be linear. Generally if you have a single non linear function the whole thing becomes non-linear if it wasn't for that then most of the sysmeteric ciphers would be useless.
     
  6. Bouncing Zabaglione Bros.

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    The answer is "sometimes it does, and sometimes it doesn't". The algorithm uses full trilinear when it decides the textures warrent it. When the textures don't need it, levels drop down towards bilinear.

    Bearing in mind that even "full trinlinear" is not going to be bitwise exactly the same as any other ATI or Nvidia version of full trilinear, and so it becomes a question that isn't really answered with a simple "yes or no".
     
  7. FUDie

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    In any event, it is still piecewise linear.
    Since when did NVIDIA have the "best trilinear"? With NV40 you could perhaps argue that the new LOD selection function is more precise, but that doesn't affect trilinear, only the coefficient used. Of course, if brilinear is used, then it may not matter much that this new LOD function is in use. Anyway, none of this pertains to what "vidia has done in the past".
    Actually it says the opposite.

    -FUDie
     
  8. Bjorn

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    Yep, people need to make the distinction between AF and trilinear. Nvidia clearly had the best AF quality on the GF3-4 generation of cards. Dunno about the trilinear part though but certainly not any worse then what the best cards today can product. Rather scary actually since we're talking about cards that in most cases can run 1600*1200, 8+X AF and 4X+ MSAA at acceptable framerates.
     
  9. croc_mak

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    Do you mean to say that there is no conditional step in "true trilinear" calculations...AFAIK, what people call "true trilinear" is the same equation you have that you call a LIE with the "Threshold" set to 0.


    Dude..You are getting confused between lod-calculation and trilinear. Yes - I do remember that Nvidia had good lod-calculation. Good lod-calculation leads to good trilinear...but all the FULL trilinear thing is a big nonsense..I'm surprised you throw out equations like you are in the know...

    There is no such thing as full trilinear or half trilinear..do you eliminate mip-map transition boundaries or do you not is the only valid question...
     
  10. Mephisto

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    That "chat" was a big joke, a big waste of time. They only answered the questions where they had prepared PR polished answers in the back. Lots of questions, although they have been asked polite and made sense in the context, haven't been answered at all. The behaviour of these two engineers was quite arrogant. You can't threat the community like this.
     
  11. Mephisto

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    Sorry, but the slider for texture filtering quality is already there, so changing the maximum quality setting to standard trilinear doesn't add any complexity at all.
     
  12. Mephisto

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    One more lie. Users here have proved that WHQL doesn't test trilinear filter quality at all.
     
  13. Richthofen

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    this chat was a piece of .....

    They are cheating their ass of got caught with their paints down and know it.
    The chat was just damage control. Bottom line remains. They are cheating.
     
  14. Quitch

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    As they say, trilinear is a compromise between "too blury" (the blending between mip levels... blending the right word?) and "too sharp". I don't see the obsession with trilinear, it's a compromise just like everything else in graphics, and if it can be improved upon, why not? Trilinear is NOT the best filtering method in EVERY situation, so why apply trilinear to everything? What is it with this love of the "one-size-fits-all" solution? People rant about relying on global CP settings, but when ATI come up with a solution for something that adapts to the situation, people complain about that.

    I think people are just upset they didn't receive a personal e-mail from ATI telling them what they did.
     
  15. Hanners

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    I also think some people need another reminder as to the meaning of the words 'cheat' and 'optimisation'....
     
  16. Blastman

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    These accusations of cheating are ridiculous.

    The X800 is doing as good a job or better filtering mipmaps transitions as any other card out there that is also doing Trilinear. So how is this a cheat?
     
  17. FUDie

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    Is that so? :lol:

    -FUDie
     
  18. gkar1

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    wow some of these responses are simply retarded(the flaming ones of course :roll: )
     
  19. CyanBlues

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    its a cheat cuz they tried to hide it. how much you wanna make a bet that if nvidia implemented this, and tried to hide it, everyone would be calling it a cheat. i mean just look at brilinear among other things nvidia's done with lil iq loss that everyone still consider it a cheat :roll:
     
  20. Quitch

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    They didn't mention their shader compiler, but that doesn't make that a cheat. Nor has anyone shown this method to reduce the IQ of images... in fact it has the potential to improve IQ.
     
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