xenocara/doc/gl-docs/GL/gl/edgeflag.3gl
2006-11-29 17:00:35 +00:00

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'\" e
'\"! eqn | mmdoc
'\"macro stdmacro
.ds Vn Version 1.2
.ds Dt 24 September 1999
.ds Re Release 1.2.1
.ds Dp Jan 14 18:30
.ds Dm 01 edgeflag.
.ds Xs 46953 4 edgeflag.gl
.TH GLEDGEFLAG 3G
.SH NAME
.B "glEdgeFlag, glEdgeFlagv
\- flag edges as either boundary or nonboundary
.SH C SPECIFICATION
void \f3glEdgeFlag\fP(
GLboolean \fIflag\fP )
.nf
.fi
.SH PARAMETERS
.TP \w'\f2flag\fP\ \ 'u
\f2flag\fP
Specifies the current edge flag value,
either \%\f3GL_TRUE\fP or \%\f3GL_FALSE\fP. The initial value is \%\f3GL_TRUE\fP.
.SH C SPECIFICATION
void \f3glEdgeFlagv\fP(
const GLboolean \fI*flag\fP )
.nf
.fi
.SH PARAMETERS
.TP
\f2flag\fP
Specifies a pointer to an array that contains a single boolean element,
which replaces the current edge flag value.
.SH DESCRIPTION
Each vertex of a polygon,
separate triangle,
or separate quadrilateral specified between a \%\f3glBegin\fP/\%\f3glEnd\fP pair
is marked as the start of either a boundary or nonboundary edge.
If the current edge flag is true when the vertex is specified,
the vertex is marked as the start of a boundary edge.
Otherwise, the vertex is marked as the start of a nonboundary edge.
\%\f3glEdgeFlag\fP sets the edge flag bit to \%\f3GL_TRUE\fP if \f2flag\fP is \%\f3GL_TRUE\fP,
and to \%\f3GL_FALSE\fP otherwise.
.P
The vertices of connected triangles and connected quadrilaterals are always
marked as boundary,
regardless of the value of the edge flag.
.P
Boundary and nonboundary edge flags on vertices are significant only if
\%\f3GL_POLYGON_MODE\fP is set to \%\f3GL_POINT\fP or \%\f3GL_LINE\fP.
See \%\f3glPolygonMode\fP.
.SH NOTES
The current edge flag can be updated at any time.
In particular,
\%\f3glEdgeFlag\fP can be called between a call to \%\f3glBegin\fP and the corresponding
call to \%\f3glEnd\fP.
.SH ASSOCIATED GETS
\%\f3glGet\fP with argument \%\f3GL_EDGE_FLAG\fP
.SH SEE ALSO
\%\f3glBegin(3G)\fP,
\%\f3glEdgeFlagPointer(3G)\fP,
\%\f3glPolygonMode(3G)\fP