get UV's vector of a face ?

Unity Engine
1

hello,
is it possible to get UV’s orientation at a given point ?
for example a vector indicating where the U axis points to ?

i know UV has only 2 dimensions, if i could get a nearby pixel i could interpolate UV’s orientation but it’s not possible.

do you guys think there is a way to get that ?

thanks a lot

2

Generally that’s what the tangent is (for the U direction) and for the V direction you want the bitangent. Although that’s averaged between the faces connected to a vertex and stored per-vertex.

You can work out the same thing with ddx and ddy (or the OpenGL equivalents of dFdx and dFdy) on the UV and position per-fragment.

There’s some OpenGL code to do that sort of thing here;

1 Like
3

thanks millions @Farfarer
oh yes tangent… right i’m going to test that…

i tested first ddx and ddy but got zero

thanks mil