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Return a vector pointing in the same direction as another.


genType faceforward( genType N, genType I, genType Nref );
genDType faceforward( genDType N, genDType I, genDType Nref );


N - Specifies the vector to orient.
I - Specifies the incident vector.
Nref - Specifies the reference vector.


 faceforward orients a vector to point away from a surface as defined by its normal. If dot (Nref,I) < 0 faceforward returns N , otherwise it returns-N.

Version Support[edit]

faceforward (genType) 1.1+
faceforward (genDType) 4.0+

See Also[edit]

 reflect , refract 


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/.