VOGONS


First post, by Dragonslayer182

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I've recently been trying to decide on a GPU for the Athlon XP Win98SE build I made a thread about a few days ago. I've been looking around and I keep hearing about table fog. I tried to look it up online, but the only thing I found that was relevant was a vogons thread that explained a bit, but what I really want to know is how much of a visual difference it makes. Are there any pictures or videos that show the difference between a game running on a card with and without table fog support?

Discord: Dragonslayer182#8984

Reply 1 of 2, by Scali

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Table fog is also known as 'pixel fog' (https://docs.microsoft.com/en-us/windows/win3 … ct3d9/pixel-fog), where the alternative is 'vertex fog' (https://docs.microsoft.com/en-us/windows/win3 … t3d9/vertex-fog).

So it's somewhat like per-pixel lighting vs per-vertex lighting.
Per-pixel allows more detail, but how much of a visual impact that actually has, depends on how a game uses it.
I wouldn't know of a game that can use both pixel fog and vertex fog off the top of my head, so I wouldn't know an example to compare the two.

I would say that the difference is probably not that large in practice. Firstly, because in the days of fixed-function fog, the geometry didn't have that much detail anyway, so trying to add detailed fog to undetailed geometry doesn't really work. Secondly, because there was not a lot of per-pixel lighting being used at all, if any, in those days.
Once you start using shaders for per-pixel lighting, you can also create your own custom fog routines, so you would no longer rely on table fog anyway.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 2 of 2, by leileilol

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There's a lot of depth to this subject 😀

Generally when a card doesn't support table fog properly, it may either skip the fog or render nothing entirely. Usually this affects several Direct3D6 games just before the turn of the millenium.

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