White papers...

dur23

Was wondering if anyone had any white papers or how tos that i could pass along to the programmers here about implementing mirrored normal maps. I know i shouldn't be the one looking this up, but they seem to have hit a road block with their searches.

Thanks for your helpzorz in advance.

bai.

JKMakowka

Maybe just look it up in one of the open-source engines that feature that?

Keg

Route i went since I just did this was implement this code to calculate the tangents and within the shader code check to see if the w was negative. if it was, I inverted the green channel.

http://www.terathon.com/code/tangent.php

Alternate route would be to have the artists move the mirrored parts uv's over exactly one in any direction and have a check for if the uv's are greater than one or less than one invert the green channel.

CrazyButcher

that however is only needed if you actually use normal/tangent and calc binormal from them. if you feed all 3 vecs, then mirroring will work as long as mesh was split internally along seam meshes of mirrored chunks (which it has to in any case)

Eric Chadwick

Classic whitepaper from Nvidia.

GDC2002 -- Texture Space On Real Models
This presentation covers generating texture space and fixing real-world issues such as mirroring.

http://developer.nvidia.com/object/gdc_tspacereal.html

dur23

Awesome work fellas. Thanks for taking some time to help me find this stuff. I have ammo now going into conversation with the programmers.

Keg you know i heart you..

MoP

This list might be of use to someone, not really specific to what you were asking, Dur23, but there's a ton of cool stuff to be found.

http://trowley.org/