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.ds f \s-2SET REFLECTANCE EQUATION\s+2
.TH "SET REFLECTANCE EQUATION" 3P+ "29 February 1991"
.SH NAME
SET REFLECTANCE EQUATION \-  create a structure element to set
the current interior reflectance equation   
.IX "PHIGS Extension Functions" "SET REFLECTANCE EQUATION"
.IX "Aspect Source Flags" "SET REFLECTANCE EQUATION"
.IX "Filled Area Interior Attributes" "SET REFLECTANCE EQUATION"
.IX "Attributes, Filled Area Interior Attributes" "SET REFLECTANCE EQUATION"
.SH SYNOPSIS
.SS C Syntax
.ft B
.ta 1.25i 3i
.nf
void
pset_refl_eqn ( equation )
Pint	equation;	\fIreflectance equation\fP
.fi
.ft R
.SS Required PHIGS Operating States
(PHOP, *, STOP, *)
.SH DESCRIPTION
.SS Purpose
\s-2SET REFLECTANCE EQUATION\s+2 creates a structure
element to set
the current interior reflectance equation.
.LP
When the current interior reflectance equation
Aspect Source Flag (\s-2ASF\s+2) is set to
\s-2INDIVIDUAL\s+2,
the current value of this attribute
defines the interior reflectance equation
to be applied to the following output primitives:
.RS
.LP
\(bu
.SM "FILL AREA"
.LP
\(bu
.SM "FILL AREA 3"
.LP
\(bu
.SM "FILL AREA SET"
.LP
\(bu
.SM "FILL AREA SET 3"
.LP
\(bu
.SM "FILL AREA SET 3 WITH DATA"
.LP
\(bu
.SM "SET OF FILL AREA SET 3 WITH DATA"
.LP
\(bu
.SM "NON-UNIFORM B-SPLINE SURFACE"
.LP
\(bu
.SM "QUADRILATERAL MESH 3 WITH DATA"
.LP
\(bu
.SM "TRIANGLE STRIP 3 WITH DATA"
.RE
.SS C Input Parameters
.IP \fIequation\fR
The reflectance equation.  The possible values defined in phigs.h are:
.sp
.nf
.ta .5i +\w'0     'u +\w'PREFL_AMB_DIFF_SPEC     'u
1	PREFL_NONE	\fINo Reflectance Calculation Performed\fP
2	PREFL_AMBIENT	\fIUse Ambient Term\fP
3	PREFL_AMB_DIFF	\fIUse Ambient and Diffuse Terms\fP
4	PREFL_AMB_DIFF_SPEC	\fIUse Ambient, Diffuse, and Specular Terms\fP
.sp
.fi
.SS Execution
Depending on the edit mode, a \s-2SET REFLECTANCE EQUATION\s+2
element is inserted into the open
structure after the element pointer or replaces the element pointed
at by the element pointer. The element pointer is then updated to 
point to this \s-2SET REFLECTANCE EQUATION\s+2
element.
.LP
At traversal time, if the specified reflectance equation is not defined,
then the default is used.
.LP
When the current interior reflectance equation \s-2ASF\s+2 is set to
\s-2INDIVIDUAL\s+2, area-defining output primitives which follow in
the structure network are filled using the current interior
reflectance equation.
.LP
When the current interior reflectance equation
\s-2ASF\s+2 is set to \s-2BUNDLED\s+2,
the interior reflectance equation is taken from the
workstation extended representation indicated by the current interior index.
In this case, the interior reflectance equation
set with \s-2SET REFLECTANCE EQUATION\s+2 has no effect.
.SH ERRORS
.IP 002
Ignoring function, function requires state 
(\s-2PHOP\s+2, \s-2*\s+2, \s-2STOP\s+2, \s-2*\s+2)
.SH SEE ALSO
.nf
.IP
.ta 0.5i
.SM "SET INDIVIDUAL ASF (3P)"
.SM "SET INTERIOR REPRESENTATION (3P)"
.SM "SET FACE DISTINGUISHING MODE (3P+)"
.SM "SET INDIVIDUAL ASF (3P)"
.SM "SET INTERIOR REPRESENTATION PLUS (3P+)"
.SM "SET REFLECTANCE EQUATION (3P+)"
.SM "FILL AREA (3P)"
.SM "FILL AREA 3 (3P)"
.SM "FILL AREA SET (3P)"
.SM "FILL AREA SET 3 (3P)"
.SM "FILL AREA SET 3 WITH DATA (3P+)"
.SM "SET OF FILL AREA SET 3 WITH DATA (3P+)"
.SM "NON-UNIFORM B-SPLINE SURFACE (3P+)"
.SM "QUADRILATERAL MESH 3 WITH DATA (3P+)"
.SM "TRIANGLE STRIP 3 WITH DATA (3P+)" 
.fi