Mip Map help!

BrendtheCow

So, after implementing some relief mapping on a piece of terrain we've run into an issue with aliasing/flickering when moving around. http://www.drobot.org/pub/M_Drobot_Programming_Quadtree%20Displacement%20Mapping.pdf points to a promising solution, but there's a catch: it requires mip maps for the relief maps to be generated using a min rather than an average function (wherein 4 pixels sampled would choose the darkest pixel, and put that into the mip map rather than averaging the grey value of all four pixels).

I have no idea how to do this, nor can I find a method for it. It doesn't seem to be supported in nvidia's .dds exporter. Anyone here know how I can save out min mip maps instead of average mip maps, or if someone has published a Photoshop script/action for doing it online somewhere?

Thanks!

dpadam450

I can probably get you a simple program to do this for 30-50 bucks. Unfortunate if there isn't anything already out there you can't find though.

Eric Chadwick

You could do this with an Action in Photoshop, but it would only work for the same resolution texture that you built it for.

Resize the canvas, scale down the original texture and put it next to the original, do a Min on it, repeat until you get to the smallest mip. Then tell Nvidia's dds tool to use existing mips.

mikiex

The issue with photoshop is that its resampling did not take into account gamma correctly last time I checked.

bac9-flcl

Wasn't there a window in NVIDIA DDS Plugin that allowed you to select whatever mip filtering method you want? Certainly not something to do manually, I'm sure there was a way.

Eric Chadwick

Screencap from the latest. Maybe one of these duplicates the min behavior?

BrendtheCow

Trying to find documentation somewhere on the Filter Types now, to see if them mimic a min function. Thanks, all! If worst comes to worst, I can script it. I was just hoping to avoid that, lol.

equil

the nvidia texture tools let you edit mips in photoshop. it's kind of obtuse (mostly since there arent any image formats that support multires images), but it should be possible to do it there.