Does anti-aliasing cause blurring?

[Humbug]

A few months back I read the below article

http://www.tweakguides.com/Crysis3_6.html

 

It also gives interactive comparisons between AA on and AA off. When I drag the slider across personally I notice that despite the reduced aliasing, all AA modes apart from MSAA seem to be causing significant blurring? TXAA being the worst offender. If you zoom into the interactive comparison it becomes even clearer- Anti aliasing can remove that sharp look of textures...

 

Discuss.

[ILoveShaders]

Anti-aliasing is the process of reducing high frequencies from a signal. In our case the signal is a picture and the high frequencies are abrupt changes in color (our "jaggies").

 

Different types of anti-aliasing find these jaggies in different ways, in the case of MSAA it only looks for jaggies at the edge of a 3D object because it is done at the rasterization/interpolation stage of the rendering pipeline.

 

The other methods (FXAA and TXAA) are post-process methods, that means they perform the "smoothing" of the image after the whole frame was rendered. The algorithm then looks for "jaggies" EVERYWHERE in the image, it does not know where the edges of the objects are, it just sees a picture. Because the computer can't tell objects apart, just numbers, these techniques can't tell the difference from "jaggies" at the edge of the object (the ones we want to eliminate) and sudden changes in color within a texture (the ones we don't want to eliminate).

 

Because of this "FXAA" and "TXAA" also smooth textures a little. So yes, they can make textures a little bit more blurry because of this.

[Humbug]

i had heard about possibility of blurring before but didn't realize it was this significant. Will have to try and stick to MSAA from now on..

[MzCatieB]

no AA makes things cleaner.... motion blur causes bluring

[jbr]

Crysis 2 and 3 are an ugly console port mess anyways regardless of what you do.

[nightlitezzz]

I believe FXAA is the only one that will make AA look blurry, the other versions are fine. 

[Humbug]

I believe FXAA is the only one that will make AA look blurry, the other versions are fine. 

Well according to this comparison TXAA is even worse than FXAA