REFRACT(3G)

NAME
refract - calculate the refraction direction for an incident vector

DECLARATION

genType refract(genType I, genType N, float eta);

genDType refract(genDType I, genDType N, float eta);

PARAMETERS

I
    Specifies the incident vector.

N
    Specifies the normal vector.

eta
    Specifies the ratio of indices of refraction.

DESCRIPTION

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.

VERSION SUPPORT
 | OpenGL Shading Language Version
Function Name | 1.10 | 1.20 | 1.30 | 1.40 | 1.50 | 3.30 | 4.00 | 4.10 | 4.20 | 4.30 | 4.40 | 4.50
refract (genType) | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔
refract (genDType) | - | - | - | - | - | - | ✔ | ✔ | ✔ | ✔ | ✔ | ✔

SEE ALSO

dot(), reflect()

COPYRIGHT

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. http://opencontent.org/openpub/.

COPYRIGHT
Copyright © 2011-2014 Khronos Group