Anti-Aliasing

[Krusty]

FSAA was put on vid cards back when resolutions were much lower. Think about it. AA is just smoothing out the steps between pixels because the pixels aren't fine enough to do it themselves.

However, nowadays with resolutions much higher than before, you really will not see as much a boost with FSAA as you will on, say, an 800x600 game, or a 1152x864 game. It's still noticable on 1280x1024, but when you get up to 1600 resolution (or higher) you're almost unable to see any difference because you have literally a million more pixels to work with comparing 1024 to 1680 resolution.

If you don't see the difference at 2x or 4x, just leave it off for your particular setup. I played HL2 Ep2 on a 32" hidef TV with FSAA turned off and it still looked smooth as hell (no jaggies) because of the resolution I was playing with.

[Krusty]

I took a couple in game screenshots to give you a better idea of what AA does for you in game.  These are taken at 1280x960.  This one is with AA set to 8xS:

This one is with AA off:

You can really see the difference on the canopy, the edges of the runway, and the Quonset huts, but it is really noticeable on stuff like the radar tower to the right.

Matter of fact, I don't see too much of a difference. I think you have the same problem I do, where screenshots don't show the FSAA that your monitor is actually rendering. I haven't been able to get FSAA to show up properly in screenshots for years now. Something from way back a bit after AH2 came out, some graphics update changed it and since then I can see the difference in-game, but not in screenshots. Try using "prntscrn" and pasting into a bitmap, that might work.

[Yippee38]

Matter of fact, I don't see too much of a difference. I think you have the same problem I do, where screenshots don't show the FSAA that your monitor is actually rendering. I haven't been able to get FSAA to show up properly in screenshots for years now. Something from way back a bit after AH2 came out, some graphics update changed it and since then I can see the difference in-game, but not in screenshots. Try using "prntscrn" and pasting into a bitmap, that might work.

I disagree.  I can clearly see the difference.  Take a look at the upper corners of the canopy frame, and the canopy frame at the top (vertical line).  You can see the jaggies pretty clearly there.  However, the bb did shrink the images a bit.  Try right-clicking on them, select "copy image location," and pasting that into the location bar of a new browser tab.  That will give you the full-size image.  Another place it is really noticeable is on the left side of the top of the instrument panel above the horizon.  You can see how it steps upward there, but looks fairly smooth in the AA shots.

Here's the same scene at 1600x1200 with no AA.

[Shuffler]

i run 70fps in a furball right now how much of a decrease in performance could AA have

AA can decrease your performance down to zero instantly. ummm oh..... I thought you meant Anti Aircraft. Never Mind (said in my best Gilda Radner)

[HomeBoy]

A bunch of us hashed this through earlier this year and these are the settings I et. al. worked out to be the best for the Nvidia 8800:



Interesting comment Waffle makes about turning AA-transparency off which I did not do.  I'll have to go back and try it with that setting off and see what difference it makes.  My FR stays pegged at VC (60Hz) which is maybe why I never really noticed any difference here.

Thanks for that tip Waffle.

[Engine]

you really will not see as much a boost with FSAA as you will on, say, an 800x600 game, or a 1152x864 game. It's still noticable on 1280x1024, but when you get up to 1600 resolution (or higher) you're almost unable to see any difference because you have literally a million more pixels to work with comparing 1024 to 1680 resolution.

Sorry, I have to disagree. I play at 1600x1200, and the difference is immediately noticable, especially with objects at range. Have a look at the hangar in Yippee's screenshot: With AA on, it appears distinctly as a hangar... with AA off, it's harder to identify because it's a jumbled mass of pixels.

[Krusty]

I do notice a minor change in the appearance of the hangars in the distance, but the difference is minute. He says he's running 1650 but the image he posts is 1024 (1,000,000 pixels less resolution, justabout). Is he down-sizing these pics, or is he mistaken in his resolution settings? If downsizing, it's going to resample both images (effectively making them look the same). I'd like to see a raw sample of 1650 non-AA scaled down to match the same measurements as a 1024x768, and then see what the difference is. The number of pixels themselves act as the FSAA.


When I look at the hangars, the only detail difference other than slightly smoother edges, is the window detail on the one on the left side (11 o'clock). I wonder if somehow the screenshots aren't showing what they ought, because they are resized. 

[Engine]

They're being resized by the BB to 10x7, but if you right-click, hit Properties, and copy/paste the address into a new web page, you can view both images at 1280 x 960. Align the image properly, then just click back and forth between windows to check for differences. You should immediately notice the difference between hangars, trees on the right-hand skyline, the HUD projector, the radar antenna, the water tower framing, etc etc etc.

I can immediately notice the difference at 1600 x 1200, and IMO it's bad enough to make playing less enjoyable, so I have AA on. I wouldn't mind an ingame setting, as most games provide, but I'm fine using the nVidia controls as well.

[LePaul]

Maybe its my eyes....but in those screen shots, the outer enges of the canopy frame is jagged on both samples.  As for the rest...I couldnt see much noticeable

I just want the trees to display 5 miles out, not 300 yards off my nose 

[Krusty]

They're being resized by the BB to 10x7, but if you right-click, hit Properties, and copy/paste the address into a new web page, you can view both images at 1280 x 960.

Thanks! I didn't realize the BBS was doing that.

I can notice a difference when they're not down-scaled like that.

Can you, next time you have some time to spare, take a similar set of pics? Take one with no AA at your higher resolution, and then drop it down to 1280 or 1024 and put AA back on and take another? I'm curious about something. You take a screen that has 19" but maxes out at 1280 resolution, and you take a screen that has 22" at 1600 resolution, and the pixels must physically be smaller on the hi-res monitor, meaning denser pixels, more detail, and I wonder if the higher pixel count but similar size makes up physically (rather than electronically) for the need to use FSAA.

[Engine]

Sure, I'd be happy to, Krusty. It'll have to wait until tomorrow - tonight I won't be home. I'll also do one pic with ultra ridiculous maxed-out settings, just for kicks.

Hmmmm, I have to try an experiment. iirc, nVidia won't apply Anisotropic filtering or AA to objects at certain distances, but there's a third-party program that changes this. I remember the huge difference it made with Silent Hunter III. Gotta try it here.

LePaul: Objects being drawn at a further distance - this can be controlled by one of the slider settings you can change from within AH2 (provided your system is powerful enough to take the performance hit), I think. I'm sorry I can't tell you which one, because I'm not home. It might be labeled LoD (Level of Detail) or Draw Distance... something like that.

[715]

Anti-aliasing doesn't just make the edges of lines look less jaggy.  That's not where the "alias" comes from.  Alias refers to where the screen doesn't have the resolution to display all the polygons (or all of the structure in the polygon texture) and it creates a Moire like ugly pattern.  It is similar to what happens if you don't analog filter A/D inputs and digitize a high frequency sound at sample rates that are too low- you get "aliases", ie sounds at frequencies below that of the true sound. 

Think of a black and white checkerboard floor that goes off into the distance.  At the point where you can't resolve a black tile from a white tile it should show up as a smooth grey.  Instead you get either a black pixel or a white one and the "beat" frequency between the screen resolution and the finer real object resolution shows up as a very ugly Moire like pattern.  This is even more true for texture patterns like chain link fences.  Instead of turning gray in the distance they turn into ugly patterned bars that move all over as you change your view of them or get closer or farther away.  That is why I choose to enable not only normal anti-aliasing, which works only on the edges of polygons, but also transparency anti-aliasing (or adaptive anti-aliasing) which works on the textures within polygons.  And yes, the graphics card has to work much harder to anti-alias as it is rendering at higher resolution and down sample averaging.  (Not really, exactly, as the algorithms the cards use are more sophisticated and, indeed, not as good.)  In my case it doesn't matter.  My Radeon 4850 can easily handle it.

[Yippee38]

it creates a Moire like ugly pattern.  It is similar to what happens if you don't analog filter A/D inputs and digitize a high frequency sound at sample rates that are too low- you get "aliases", ie sounds at frequencies below that of the true sound.

Can you post an example of that from AH?  I've never noticed that, but then again, I've never looked for it either.

[715]

Can you post an example of that from AH?  I've never noticed that, but then again, I've never looked for it either.

It used to show up most obviously on the chain link fence object, but those have been removed from AH these days.  On all other objects the effect is too subtle to worry about (like on the steel roll up doors of the small square buildings).  Also, a static screen shot doesn't do it justice as it is the dynamic shimmering/changing that occurs as you move your view angle that stands out the most.