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Syan
09-02-03, 12:49 AM
Hey guys, just got my 5900-equiped system and I noticed below the AA and AF sliders there is yet another option called Texture Sharpening. I'm not quite sure how it effects the games (besides the obvious), do you guys recommend keeping it off or on (considering how it may effect performance)?

fivefeet8
09-02-03, 12:52 AM
It increases the AF level to the next higher option up to 8x. Maybe it does something else, but that's what it says in the driver help.

You should try the "image sharpening" slider in the "digital vibrance" controls. ;)

ChrisRay
09-02-03, 12:54 AM
Originally posted by fivefeet8
It increases the AF level to the next higher option up to 8x. Maybe it does something else, but that's what it says in the driver help.

You should try the "image sharpening" slider in the "digital vibrance" controls. ;)


You just love that dont you?


If I ever get my hands on an FX card I'll have to try it.

Syan
09-02-03, 12:55 AM
Does image sharpening affect my games as well?

fivefeet8
09-02-03, 12:59 AM
Originally posted by Syan
Does image sharpening affect my games as well?

Yes..

Syan
09-02-03, 01:00 AM
The image sharpening works a lot like the sharp option for a T.V. It makes my deskop and applications look sharper, but maxing the slider makes it too sharp. How does the image sharpening correlate with AF and AA?

Kruno
09-02-03, 01:17 AM
TS basically doubles the level of AF used.
IE: 2xAF -> 4xAF

BUT it can't take AF over 8x.

ADD: Needs AA enabled to work.

Syan
09-02-03, 01:18 AM
So with AF off completely, that sets the texture sharpening to 2x or it doesn't do anything?

Greg
09-02-03, 01:38 AM
Texture sharpening samples the texture at the (larger) anti aliased resolution. So without this option on, you pretty much get the effect of anti aliased 'edges', but with this on, you get much higher quality texture between those triangle edges. Take a couple of screen shots with and without this option on, and you you'll see what I mean. This option is meaningless without FSAA modes because the texture is already sampled relative to the screen resolution using one of the mip filter options. Note that the latest ATI cards appear to sample textures at the higher res always (this is a major, but not the sole reason reviews often prefer radeon fsaa). Please do not post any ATI related comment.

gokickrocks
09-02-03, 02:04 AM
it does not sample at a higher resolution, nor does it do any antialiasing...

Syan
09-02-03, 02:23 AM
It only works during anti-aliasing anyhow.

particleman
09-02-03, 02:36 AM
Texture sharpening doesn't appear to do the same thing as AF since all the mip map transitions stay at the same relative positions, they don't get pushed further into the distance like when you turn on AF. What Greg said does make sense though.

As for the Image sharpening slider, if you want to see the effect, but don't have a GeForceFX just use photoshop or paintshop pro and use the sharpen filter. Just like the sharpen filter you will see the same types of grain artifacts and outlines around stuff when it is applied too much. I prefer to leave it off myself.

StealthHawk
09-02-03, 03:28 AM
Originally posted by particleman
Texture sharpening doesn't appear to do the same thing as AF since all the mip map transitions stay at the same relative positions, they don't get pushed further into the distance like when you turn on AF. What Greg said does make sense though.

They do push back mipmap levels...just like AF :p

Greg
09-02-03, 07:59 AM
Originally posted by particleman
Texture sharpening doesn't appear to do the same thing as AF since all the mip map transitions stay at the same relative positions, they don't get pushed further into the distance like when you turn on AF. What Greg said does make sense though.

Originally posted by StealthHawk
They do push back mipmap levels...just like AF :p

They certainly do. AF gets a chance to do more work!

The way texture sampling works is to 'attempt' to keep the texel to pixel ratio at 1. So if the texel on screen is small, it finds a mip level that matches, if the texel is large, that's too bad, it has to bilinear filter magnify (blur / interpolate) it up. But the interesting things happen with minification. Because it will rarely find a 1 to 1 match, it will pick one or more (up to hundreds) samples from one or more (up to 12 or so) mip levels in order to give a accurate final sample.

Now what anti aliasing does is actually, or logically create a higher resolution output. (Although many other methods such as blur filtering the output exist). If you run at high resolutions, you see much more of the higher level mips, if you run at 320x240, you will probably never see any of the top levels of say a 512x512 or larger size texture (unless you use high levels of AF, or FSAA with texsharpening on).

The FX cards actually get quite a speed boost from not sampling all those extra texels with FSAA, by default, as it would otherwise use lots more memory bandwidth.

So go on, take some screen shots at different resolutions such as 640x480 and 1280x960, with FSAA on/off and Texture Sharpening on/off and see what I am talking about. It will all become clear, well, at least blury around the edges ;)

EDIT: I just re-read the original post and a once sentence answer is:
"This option makes textures in your games look better when using antialiasing, but will make the game run somewhat slower."
Some benchmarks might help Syan decide weather to leave it on, or off.

Skinner
09-02-03, 12:56 PM
Originally posted by fivefeet8

You should try the "image sharpening" slider in the "digital vibrance" controls. ;)

Yes that's a sort of lodbias setting, I really mis that in the ati drivers.

fivefeet8
09-02-03, 11:36 PM
Originally posted by Skinner
Yes that's a sort of lodbias setting, I really mis that in the ati drivers.

The difference is that LOD bias doesn't work in everything, while the "image sharpening" slider does. Desktop, 2d, 3d.. ect.. And LOD bias has a little affect on performance. The "image sharpening" slider doesn't seem to have any performance hit at all.

Skinner
09-03-03, 05:58 AM
Indeed lodbias only works for big angle views.