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ATI cards, CM, and Fog


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I know there is a long standing issue with Fog, ATI and CMBO -- namely: it don't work! :(

So a few questions,

Does anyone know why this is?

...and perhaps more importantly -- will this still be an issue with CMBB?

Also, what fog graphics mode is used in CMBO? I have just started using a tweaking utility for my Radeon 8500 and a couple of the tweaks available for it are "Enable Table Fog", "Enable W Fog", and "Enable Z Fog". I was hoping that setting one of these might cure the problem, but alas no.

Anyone have any further info on this problem and maybe a possible fix?

TIA

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Fog tables don't work with ATI video cards and DirectX. They work in RAVE on the Mac, but ATI has never gotten to the point of supporting fog tables to the proper extent in DirectX.

Tweaker programs will not fix the problem. The driver code just isn't there to properly support fog tables.

This, unfortunately, will probably remain a problem with CMBB. The only recourse to this is to use a different method of generating fog, but that can be a significant framerate/performance hit (vertex fog, a.k.a. w-fog ?) and it won't be supported by quite a few cards (though that is becoming less of an issue since NVidia and ATI almost completely dominate the market).

ATI made patches in the past to their drivers (I remember specifically beta drivers for the Rage 128 and early Radeon chips) to 'fix' problems with fog-tables, but they never worked in CMBO. I don't expect that ATI will really fix this issue at any point. Since it isn't a feature used in most FPS/Action games it doesn't really register with them as something that needs to be addressed.

[ May 29, 2002, 01:46 AM: Message edited by: Schrullenhaft ]

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Schrullenhaft,

Thanks for the detailed explanation...i was afraid this might be the case.

If it is right that CMBB will also probably not support fog with ATI cards then i will just have to get another card. Alternatively, and considering how popular ATI cards are, i hope BTS can sort out some sort of work-around for this problem.

Thanks Again!

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  • 3 weeks later...

Which games do you play that show fog ? Are they DirectX or OpenGL ? It's possible that these games aren't using fog-tables, but vertex-fog (W & Z fog ?). I'm not sure what the visual or actual coding differences are between the two, but I know that ATI has had problems with other games that support fog-tables. I know Charles chose to use fog-tables rather than vertex-fog because more cards (at the time) supported fog-tables. There may also be performance or appearance reasons for using fog-tables (not sure on that).

On the Mac it is no problem and I'd guess under OpenGL they may have no problems there either. Since ATI has 'rededicated' itself to release more frequent driver updates (for at least the Radeon family) maybe one day we'll see fog-table support under DirectX.

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Since ATI has 'rededicated' itself to release more frequent driver updates (for at least the Radeon family) maybe one day we'll see fog-table support under DirectX.
lets hope so smile.gif

Ya, but if you want fog in CM, get the cheap GeForce.
ive been playing this game for over a week now and im having fun, fog or no fog im enjoying this purchase :D
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