Located "artifacts" appears on some games; what would have generated it?

By franklogus
Aug 8, 2004
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  1. Hi all !
    I am having a strange problem with my video card... I have a MSI 9800 PRO PLUS Card, and I got it 03 weeks ago...
    I will try to explain what happens; its difficult to explain, although very easy to see... Sorry if my explanation is a bit confused... (My OS is WinXP PRO SP1)
    Well, I like racing games, and, since the morning of today, I can see some "drizzle" (as "TV interference") in the shadow of the cars (in other words, the problem ONLY appears in the dark/black shadow where the cars go by...). It seems some very small artifacts, but ONLY on the cars shadows (so, I can see the "ground color", in some parts of the shadow). Its very, very strange, because looks like that the shadow is "perforated", and its possible to see what would be "under" it ("the ground")...
    I didn't make nothing different with my video card (it was working very well until yesterday - no problems). I have already re-installed my video card driver, but the problem keeps on ... My single suspicion concerning to a game that I have installed (4x4 EVO2), and, inside which, I choose 02 different ways of rendering (Open-GL and Direct3D8 TNL Hardware). I am not sure, but I think that this strange problem can have begun after this...
    As I didnt tried any kind of overclocking, and the problem ONLY (VERY specific place) appears on the cars shadows (when they are in ACTION) - not on the others eventual "black/dark" parts of the screen -, at first view, I can not believe that my video card is with some problem of hardware... Anyways, I would like some skilled opinion about...
    I would like to clarify that this specific problem does not happens in ALL games I have, but in some of them...
    Some hints about what is happening? And what could I do to solve it, please ??
    Thanks a lot in advance for any information!!
  2. DigitAlex

    DigitAlex TechSpot Paladin Posts: 583

    I don't know for sure, but sometimes when the 3D developers implement some stuff in a strange way, such things can happen.
    Let me explain my idea.
    It's possible though very strange that they have implemented shadows on the ground by applying an additional polygon (coloured in black / dark) just on top of the ground itself. It would not be usual but it's possible. In that case, if you try to draw more than one polygon belonging to the same plane on top of each other (for example ground + shadow or wall + poster, etc) then the 3D API does not know which one is on front of the other (because none is in front, they have exactly the same coordinates for that plane). Then, sometimes some pixels belonging to the shadow and some to the ground are displayed, randomly. I'm gonna try to find a picture illustrating that behaviour. If that is what happens, there is nothing to do but fire the developers of the game ;) Seriously, a special extension allows developers to do the same thing (2 polygons on 1 plane) without such glitches, but it has to be in the code of the game, so there is no way to fix it afterwards. Not dure if its what's happening. Try to post a screenshot of that area, so people can see it clearly.
  3. DigitAlex

    DigitAlex TechSpot Paladin Posts: 583

    What I was thinking about is called "z-fighting".

    Here is an example :

    [​IMG]

    And here is what it should look like once polygon offset filling has been enabled by the developer :

    [​IMG]
  4. franklogus

    franklogus Newcomer, in training Topic Starter Posts: 64

    Thanks for your answer, DigitAlex !

    Well, I can say to you that, probably, what happens is what you show in these draws, but the "polygons" (or something like this) would be in a big number and are very, very small (that's because I can not affirm that the "artifacts" have the format of "polygon"). And it occurs in a random way, on the "moving" shadows of the cars (NOT all the time...)

    As I have said, its difficult to explain what happens (it only happens (NOW) in some games, as Mercedes Benz World Racing and 4x4 EVO 2 - I need to say that I suspect that, before I have installed this last one, the other (Mercedes Benz W.R.) was running perfectly - so, it is not "fault" of game developers ..). When I am running EASPORTS or CODEMASTERS racing games, I can't see this problem...

    I will try to capture some screenshot, but I can to advance that it will be very hard to get it, in a way that it will be observable...

    In another forum, I was advised to run the 3Dmark03 benchmark, to see if this problem also occurs (perhaps it would be much heat on case...). But I have one question: If there is some "weakness" of my video card (Its a very new device; I wouldn't like to know that it is with some problem..), is there some danger of to "hurt" it until more if I will run this benchmark program?

    Thanks in advance for any additional information!
  5. DigitAlex

    DigitAlex TechSpot Paladin Posts: 583

    I dont think you can hurt it unless it overheats really too much, which doesnt seem happening cause all the other things work fine, you said.
  6. Didou

    Didou Bowtie extraordinair! Posts: 5,899

    Try taking a screenshot (PrintScreen key) & then upload it to the gallery or somewhere like ImageShack.

    If you believe it to be caused by overheating, lowering the speed of the core/mem should make the artifacts go away or maybe opening the case & having a heavy-duty fan blow straight on it. Have you tried that ?
  7. franklogus

    franklogus Newcomer, in training Topic Starter Posts: 64

    Thanks for your help ..
    I have already uploaded 03 screenshots of this strange problem ... Please, pay attention on the shadow of the blue car ...

    Thanks a lot in advance for any additional help !
  8. franklogus

    franklogus Newcomer, in training Topic Starter Posts: 64

    I have uploaded in the game section gallery ..
  9. DigitAlex

    DigitAlex TechSpot Paladin Posts: 583

    Hmmm, it's not z fighting

    but it seems a game specific problem to me though
  10. franklogus

    franklogus Newcomer, in training Topic Starter Posts: 64

    Sorry, but what means "Z fighting"???
    The problem began last sunday; this same game (of the screenshot) was running perfect (wiyh NO "artifacts") on saturday ...
  11. DigitAlex

    DigitAlex TechSpot Paladin Posts: 583

    Did you read what I posted above ?
  12. franklogus

    franklogus Newcomer, in training Topic Starter Posts: 64

    Oppppssss... Sorry, DigitAlex !!
    I am not accostumed with these "technical" words...
    Yes, I have read it and I thank you very much for your attention; I apologize for my mistake!
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