Fresnel VEX node
Computes the Fresnel reflection/refraction contributions given a normalized incident ray, a normalized surface normal, and an index of refraction.
The amount of reflected light will be returned in kr, and the amount of transmitted light will be returned in kt. Optionally, the reflection and transmission vectors can be returned in the R and T variables. Both R and T will be normalized.
The global variables I and N will be used if the incident vector and surface normal inputs are not connected. If connected, the N and I vectors must be normalized.
kt is scaled by the index of refraction (
eta) which may make the value non-intuitive. To eliminate this, divide the
kt returned from
fresnel function by the index of refraction you passed in.