Futuremark: 3DMark06

Discussion in 'Graphics and Semiconductor Industry' started by trinibwoy, Dec 23, 2005.

  1. KimB

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    That looks like precision problems. Interesting. Well, these were beta drivers for the X1900, so no conclusion should be drawn for at least two weeks.
     
  2. Geo

    Geo Mostly Harmless
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    Well, I asked him that: http://www.elitebastards.com/forum/viewtopic.php?t=13550
     
  3. Xmas

    Xmas Porous
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    Just because a pixel isn't inside the edge mask doesn't mean it's not a penumbra pixel. If you take 8 "outer" samples first, the results are likely very similar to those of an edge mask. And generating an edge mask needs sampling from the shadow map, too.
     
  4. Jawed

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    In (corrected link):

    http://www.ati.com/developer/SIGGRAPH05/ShadingCourse_ATI.pdf

    page 21 it says:


    It seems to me that the edge map encompasses the entire penumbra, rather than being "1 pixel" thick along "edges".

    Jawed
     
    #644 Jawed, Jan 27, 2006
    Last edited by a moderator: Jan 28, 2006
    OpenGL guy likes this.
  5. Moloch

    Moloch God of Wicked Games
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    Well said mate :grin:
     
  6. Xmas

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    That's not what I meant. As you are using a finite resolution shadow map, you can miss "single pixel penumbras". It's almost the same with taking 8 "outer" samples first.

    btw, your link doesn't work.
     
  7. Jawed

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    I corrected the link - copy and pasting from another posting used the truncated-display version :cry:

    I can't figure out what a single pixel penumbra is. Is that a penumbra that should be one pixel wide? Or do you mean penumbras due to particles? :oops:

    Jawed
     
  8. Xmas

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    I mean a penumbra that is just (less than) a single pixel wide. Both approaches have the same problem: sampling gaps.
     
  9. Jawed

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    Thanks.

    What's puzzling me is whether these algorithms are attempting to vary the penumbra width as the depth-ratio: light-blocker/light-receiver varies. The edge map on page 21 sort of looks like it varies in thickness.

    It seems to me that the kernel should vary in diameter as the ratio changes. I'm not sure if that would help with the < single pixel penumbra problem, though.

    Jawed
     
  10. Geo

    Geo Mostly Harmless
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    Hexus up with a long, thotful analysis: http://www.hexus.net/content/item.php?item=4599

    There are many interesting points, technical and, err "political" (for lack of a better term) to point at, but from a summarization pov what really struck me as "the money shot" is about mid-article:

     
  11. digitalwanderer

    digitalwanderer Dangerously Mirthful
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    A great write up, nicely done Rys! :D
     
  12. Kanyamagufa

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    QFT - Very good article Rys. The evil git in me would love to see FM's reaction to it.
     
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