AA: Controlled by app, or set manually? Is there a diff?

[MichaelD]

I decided to see how a game (IGI-2) looked w/AA turned on. I know that I have the NVidia control panel thing set to "AA controlled by App."

I set the game's CP to 4xAA and played. First time, it locked up after about a minute (never did that before) the second time, it didn't lock up at all.

Framerate got killed (expectedly) so I knocked the resolution back to 1024x768 instead of the 1152x864 I had it at.

Just curious if there's a performance diff b/t having the app control the AA and setting manually yourself? Thanks.

 

[Lord Evermore]

No performance difference between forcing it and having it controlled by the game. Either way, the video is passing through the AA process. If it's forced, the drivers just ignore the attempt by the game to set the AA option. The game code itself doesn't care what is being done to the video after it's generated and sent to the card, so it doesn't "know" that the drivers are forcing AA mode.

I've started forcing 2X anisotropic filtering and it makes things look a bit better. I didn't really notice a difference in actual gameplay appearance with AA turned on, and never expected to. I'm too busy moving around and watching for enemies to care about a momentary jaggy edge.

 

[MichaelD]

Thanks, LE. I know what AA is; but what's the diff b/t AA and AF? AF does it's thing w/lighting, right?

 

[Lord Evermore]

Anisotropic filtering is a step above trilinear filtering (or several steps since you can do 2x, 4x, et cetera). It's not related to lighting exactly, but textures that are angled from the camera (like the Star Wars opening text, as referenced here: http://www.extremetech.com/article2/0,3973,548368,00.asp ).

AA only applies to blurring edges so there aren't any jaggies.