That is correct, but some things should be known about AF:
The most cards don’t filter AF with a trilinear filter. That is the reason for the mipmap banding.
The calculated mipmap level is not the same like for isotropic filtering, with a 4x AF the sampled texel have only 1/4 of the size of a isotropic filtered texel (all are aligned). For more information search for “Footprint Assembly”
While we’re discussing AF, even on a GeForce 8 we see lots of temporal “sparkling” at medium-to-high levels of aniso (e.g. 4+), particularly when there are high frequencies in the data (light/dark, similar to checkerboard test). This is when, say, eyepoint is 5-30 deg up from the aniso’ed poly plane, looking down at ~20-30 deg.
Yes, just like the mags, it looks fine with a static scene, but when you’re moving toward or away from it, it’s really nasty. Moving laterally, it’s fine. Also, rolling the eyepoint 45 deg (i.e. bank the eyepoint) before moving forward/back greatly reduces the artifacts, but does not eliminate them. Card is an 8800 GTX.
First of all, what is this? Is this “brilinear” being applied to AF? Is this just unavoidable inaccuracies in the AF “integration” of all the texel data?
Also, what are folks doing about it. Blurring your textures? Special filters applied when generating MIPmaps that reduce the problem? Some driver tweak to disable bilinear/brilinear cheats?
Any pointers to worthwhile write-ups on this would be appreciated.
“Brilinear” is not a technical term. It was coined by the website, that you have linked to.
What they mean with the term is, that drivers cheat. You choose trilinear filtering, but the driver reduces quality to speed things up. Instead of always looking up two mipmap levels and then always blending accurately, only in a very small segment two levels are blended, but usually only one level is accessed. This makes texture-access and filtering much less costly, but reduces the quality of all textures, that were supposed to use proper trilinear filtering.
Today most drivers have a “high-quality” mode, that you can enable in the settings dialogs. “High-quality” usually means, that such unfair tricks are definitely not used. As long as you don’t check that box, drivers do all sorts of things, that might reduce quality for the sake of higher performance.
Just for the archives, the solution under Linux (latest drivers) is to run nvidia-settings, go to “X Screen 0 -> OpenGL Settings”, and move “Image Settings” from “Quality” (default) to “High Quality”. The aniso texture filter sparkling isn’t totally cured, but it’s greatly reduced!
nvidia-settings also supports batch-loading of the nvidia-settings saved config file, so it can be set on X server startup fairly simply via xsession or xinitrc.