MI_FRESNEL
THE BOX'S MAIN HELP:
This function returns the fresnel factor.
N1 (input):
The n1 fresnel factor.
N2 (input):
The n2 fresnel factor.
T1 (input):
The t1 fresnel factor.
T2 (input):
The t2 fresnel factor.
OUT (output):
The fresnel factor.