gluTessBeginPolygon(3G)	       OpenGL Reference	       gluTessBeginPolygon(3G)



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
     nonconvex 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 like	this:


	  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);



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gluTessBeginPolygon(3G)	       OpenGL Reference	       gluTessBeginPolygon(3G)



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




















































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