REFRACT(3G)                     [FIXME: manual]                    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   | 1.10 | 1.20 | 1.30 | 1.40 | 1.50 | 3.30 | 4.00 | 4.10 | 4.20 | 4.30 | 4.40 | 4.50 |
       |Name       |      |      |      |      |      |      |      |      |      |      |      |      |
       +-----------+------+------+------+------+------+------+------+------+------+------+------+------+
       |refract    | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  |
       |(genType)  |      |      |      |      |      |      |      |      |      |      |      |      |
       +-----------+------+------+------+------+------+------+------+------+------+------+------+------+
       |refract    |  -   |  -   |  -   |  -   |  -   |  -   | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  |
       |(genDType) |      |      |      |      |      |      |      |      |      |      |      |      |
       +-----------+------+------+------+------+------+------+------+------+------+------+------+------+

SEE ALSO
       dot(), reflect()

COPYRIGHT
       Copyright (C) 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 (C) 2011-2014 Khronos Group

[FIXME: source]                   05/21/2022                       REFRACT(3G)