refract
Returns the refraction of incident vector i through a surface with normal n and ratio eta.
Returns zero if total internal reflection occurs.
Return
the refracted vector, or zero on total internal reflection
Parameters
i
the incident direction (need not be normalized)
n
the surface normal (assumed normalized)
eta
the ratio of refraction indices (n1 / n2)
Returns the refraction of incident vector i through a surface with normal n and ratio eta.
Returns zero if total internal reflection occurs.
Return
the refracted vector, or zero on total internal reflection
Parameters
i
the incident direction
n
the surface normal (assumed normalized)
eta
the ratio of refraction indices (n1 / n2)