gluBeginPolygon.3   [plain text]

'\" e  
'\"macro stdmacro
.ds Vn Version 1.2
.ds Dt 6 March 1997
.ds Re Release 1.2.0
.ds Dp May 22 14:54
.ds Dm 7 May 22 14:
.ds Xs 33625     4
.TH GLUBEGINPOLYGON 3G
.SH NAME
.B "gluBeginPolygon, gluEndPolygon
\- delimit a polygon description

.SH C SPECIFICATION
void \f3gluBeginPolygon\fP(
GLUtesselator* \fItess\fP )
.nf
.fi

void \f3gluEndPolygon\fP(
GLUtesselator* \fItess\fP )
.nf
.fi

.EQ
delim $$
.EN
.SH PARAMETERS
.TP \w'\f2tess\fP\ \ 'u 
\f2tess\fP
Specifies the tessellation object (created with \%\f3gluNewTess\fP).
.SH DESCRIPTION
\%\f3gluBeginPolygon\fP and \%\f3gluEndPolygon\fP delimit the definition of a
nonconvex polygon.
To define such a polygon, first call \%\f3gluBeginPolygon\fP.
Then define the contours of the polygon
by calling 
\%\f3gluTessVertex\fP for each vertex
and \%\f3gluNextContour\fP to start each new contour.
Finally, call \%\f3gluEndPolygon\fP
to signal the end of the definition.
See the \%\f3gluTessVertex\fP and 
\%\f3gluNextContour\fP reference pages for more details.
.P
Once \%\f3gluEndPolygon\fP is called, the polygon is tessellated, and the
resulting triangles are described through callbacks.
See \%\f3gluTessCallback\fP for descriptions of the callback functions.
.SH NOTES
This command is obsolete and is provided for backward compatibility
only. Calls to \%\f3gluBeginPolygon\fP are mapped to 
\%\f3gluTessBeginPolygon\fP
followed by 
\%\f3gluTessBeginContour\fP. Calls to \%\f3gluEndPolygon\fP are mapped
to \%\f3gluTessEndContour\fP followed by \%\f3gluTessEndPolygon\fP.
.SH EXAMPLE
A quadrilateral with a triangular hole in it can be described like this:
.sp
.Ex
gluBeginPolygon(tobj);
   gluTessVertex(tobj, v1, v1);
   gluTessVertex(tobj, v2, v2);
   gluTessVertex(tobj, v3, v3);
   gluTessVertex(tobj, v4, v4);
gluNextContour(tobj, GLU_INTERIOR);
   gluTessVertex(tobj, v5, v5);
   gluTessVertex(tobj, v6, v6);
   gluTessVertex(tobj, v7, v7);
gluEndPolygon(tobj);
.Ee
.SH SEE ALSO
\%\f3gluNewTess\fP, \%\f3gluNextContour\fP, \%\f3gluTessCallback\fP, \%\f3gluTessVertex\fP,
\%\f3gluTessBeginPolygon\fP, \%\f3gluTessBeginContour\fP