Struggling to understand how FXAA works exactly

[saskun]

Ive been stumped by FXAA for over a week, going through the Nvidia paper, source code, and some implementations online but I dont completely understand it. Parts I understand:

You look at a 3x3 block, deciding an edge and edge direction based on luminance delta values

You loop through that edge (in between pixels?, Bilinear filtering a must?) In both a positive and negative direction.

I don't understand what youre supposed to do after that. I would appreciate any help as this is driving me insane, if theres a visual explanation somewhere in detail then even better.

[ballardw]

I think you may be on the wrong forum unless you show us some SAS code that is using this "FXAA".