%mathent; ]> 2011-2014 Khronos Group refract 3G refract calculate the refraction direction for an incident vector genType refract genType I genType N float eta genDType refract genDType I genDType N float eta I Specifies the incident vector. N Specifies the normal vector. eta Specifies the ratio of indices of refraction. For a given incident vector I, surface normal N and ratio of indices of refraction, eta, refract returns the refraction vector, R. R is calculated as: k = 1.0 - eta * eta * (1.0 - dot(N, I) * dot(N, I)); if (k < 0.0) R = genType(0.0); // or genDType(0.0) else R = eta * I - (eta * dot(N, I) + sqrt(k)) * N; The input parameters I and N should be normalized in order to achieve the desired result. refract (genType) refract (genDType) dot, reflect Copyright 2011-2014 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. https://opencontent.org/openpub/.