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• Author : matthieu
  Date : 2006-11-29 17:01:51
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  Message : GLU manual pages from monolithic tree

• doc/gl-docs/GLU/tessbeginpolygon.3gl

• '\" e
  '\"! eqn | mmdoc
  '\"macro stdmacro
  .ds Vn Version 1.2
  .ds Dt 6 March 1997
  .ds Re Release 1.2.0
  .ds Dp May 02 11:53
  .ds Dm 37 tessbegin
  .ds Xs 55678 4 tessbeginpolygon.gl
  .TH GLUTESSBEGINPOLYGON 3G
  .SH NAME
  .B "gluTessBeginPolygon
  \- delimit a polygon description
  
  .SH C SPECIFICATION
  void \f3gluTessBeginPolygon\fP(
  GLUtesselator* \fItess\fP,
  .nf
  .ta \w'\f3void \fPgluTessBeginPolygon( 'u
  	GLvoid* \fIdata\fP )
  .fi
  
  .EQ
  delim $$
  .EN
  .SH PARAMETERS
  .TP \w'\f2tess\fP\ \ 'u 
  \f2tess\fP
  Specifies the tessellation object (created with \%\f3gluNewTess\fP).
  .TP
  \f2data\fP
  Specifies a pointer to user polygon data.
  .SH DESCRIPTION
  \%\f3gluTessBeginPolygon\fP and \%\f3gluTessEndPolygon\fP delimit the definition of a
  convex, concave or self-intersecting polygon. Within each \%\f3gluTessBeginPolygon\fP/\%\f3gluTessEndPolygon\fP
  pair, there must be one or more calls to \%\f3gluTessBeginContour\fP/\%\f3gluTessEndContour\fP. 
  Within each contour, there are zero or more calls to \%\f3gluTessVertex\fP. The vertices 
  specify a closed contour (the last vertex of each contour is automatically linked 
  to the first). See the \%\f3gluTessVertex\fP, \%\f3gluTessBeginContour\fP, and 
  \%\f3gluTessEndContour\fP reference pages for more details.
  .P
  \f2data\fP is a pointer to a user-defined data structure. If the appropriate callback(s) 
  are specified (see \%\f3gluTessCallback\fP), then this pointer is returned to the 
  callback function(s). Thus, it is a convenient way to store per-polygon information.
  .P
  Once \%\f3gluTessEndPolygon\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 EXAMPLE
  A quadrilateral with a triangular hole in it can be described as follows:
  .sp
  .Ex
  gluTessBeginPolygon(tobj, NULL);
   gluTessBeginContour(tobj);
     gluTessVertex(tobj, v1, v1);
     gluTessVertex(tobj, v2, v2);
     gluTessVertex(tobj, v3, v3);
     gluTessVertex(tobj, v4, v4);
   gluTessEndContour(tobj);
  .bp
   gluTessBeginContour(tobj);
     gluTessVertex(tobj, v5, v5);
     gluTessVertex(tobj, v6, v6);
     gluTessVertex(tobj, v7, v7);
   gluTessEndContour(tobj);
  gluTessEndPolygon(tobj);
  .Ee
  .sp
  .SH SEE ALSO
  \%\f3gluNewTess(3G)\fP, \%\f3gluTessBeginContour(3G)\fP, \%\f3gluTessVertex(3G)\fP, 
  \%\f3gluTessCallback(3G)\fP,
  \%\f3gluTessProperty(3G)\fP, \%\f3gluTessNormal(3G)\fP,
  \%\f3gluTessEndPolygon(3G)\fP