NAME
	  gluTessBeginPolygon -	delimit	a polygon description


     C SPECIFICATION
	  void gluTessBeginPolygon( GLUtesselator* tess,
				    GLvoid* data )


     PARAMETERS
	  tess	Specifies the tessellation object (created with
		gluNewTess).

	  data	Specifies a pointer to user polygon data.

     DESCRIPTION
	  gluTessBeginPolygon and gluTessEndPolygon delimit the
	  definition of	a convex, concave or self-intersecting
	  polygon. Within each gluTessBeginPolygon/gluTessEndPolygon
	  pair,	there must be one or more calls	to
	  gluTessBeginContour/gluTessEndContour. Within	each contour,
	  there	are zero or more calls to gluTessVertex. The vertices
	  specify a closed contour (the	last vertex of each contour is
	  automatically	linked to the first). See the gluTessVertex,
	  gluTessBeginContour, and gluTessEndContour reference pages
	  for more details.

	  data is a pointer to a user-defined data structure. If the
	  appropriate callback(s) are specified	(see gluTessCallback),
	  then this pointer is returned	to the callback	function(s).
	  Thus,	it is a	convenient way to store	per-polygon
	  information.

	  Once gluTessEndPolygon is called, the	polygon	is
	  tessellated, and the resulting triangles are described
	  through callbacks.  See gluTessCallback for descriptions of
	  the callback functions.

     EXAMPLE
	  A quadrilateral with a triangular hole in it can be
	  described as follows:

	  gluTessBeginPolygon(tobj, NULL);
	   gluTessBeginContour(tobj);
	     gluTessVertex(tobj, v1, v1);
	     gluTessVertex(tobj, v2, v2);
	     gluTessVertex(tobj, v3, v3);
	     gluTessVertex(tobj, v4, v4);
	   gluTessEndContour(tobj);
	   gluTessBeginContour(tobj);
	     gluTessVertex(tobj, v5, v5);
	     gluTessVertex(tobj, v6, v6);
	     gluTessVertex(tobj, v7, v7);
	   gluTessEndContour(tobj); gluTessEndPolygon(tobj);


     SEE ALSO
	  gluNewTess, gluTessBeginContour, gluTessVertex,
	  gluTessCallback, gluTessProperty, gluTessNormal,
	  gluTessEndPolygon