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 def-
       inition 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 tessel-
       lated, 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);





SEE ALSO

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



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