Comrade Stinger | VAVLe did it again. @comradestinger | Uploaded May 2011 | Updated October 2024, 9 hours ago.
I figured it out.
The texture consists of
one normal map for refraction,
a white, oval basetexture with a new parameter in portal 2 called "$localrefractdepth" which aparently offsets the basetexture?
anso an envmap for the cubemap.