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.rm #[ #] #H #V #F C
.IX Title "reflect Cg"
.TH reflect Cg "" "Cg Toolkit 1.5" "Cg Standard Library"
.UC
.SH "NAME"
\&\fBreflect\fR \- returns the reflectiton vector given an incidence vector and a normal vector.
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 4
\&  float  reflect( float  i, float  n );
\&  float2 reflect( float2 i, float2 n );
\&  float3 reflect( float3 i, float3 n );
\&  float4 reflect( float4 i, float4 n );
.Ve
.SH "PARAMETERS"
.IX Header "PARAMETERS"
.Ip "i" 8
.IX Item "i"
Incidence vector.
.Ip "n" 8
.IX Item "n"
Normal vector.
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Returns the reflectiton vector given an incidence vector \fIi\fR and a normal vector \fIn\fR.
The resulting vector is the identical number of components as the two input vectors.
.PP
The normal vector \fIn\fR should be normalized.  If \fIn\fR is normalized, the output vector
will have the same length as the input incidence vector \fIi\fR.
.SH "REFERENCE IMPLEMENTATION"
.IX Header "REFERENCE IMPLEMENTATION"
\&\fBreflect\fR for \fBfloat3\fR vectors could be implemented this way:
.PP
.Vb 4
\&  float3 reflect( float3 i, float3 n )
\&  {
\&    return i - 2.0 * n * dot(n,i);
\&  }
.Ve
.SH "PROFILE SUPPORT"
.IX Header "PROFILE SUPPORT"
\&\fBreflect\fR is supported in all profiles.
.PP
Support in the fp20 is limited.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
the dot manpage,
the length manpage,
the refract manpage
