GLenum which,
                                        GLdouble data )

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

       which  Specifies   the   property   to   be   set.   Valid   values  are
              GLU_TESS_WINDING_RULE,                    GLU_TESS_BOUNDARY_ONLY,
              GLU_TESS_TOLERANCE.

       data   Specifies the value of the indicated property.

DESCRIPTION
       gluTessProperty  is  used to control properties stored in a tessellation
       object. These properties affect the way that  the  polygons  are  inter‐
       preted and rendered.  The legal values for which are as follows:

       GLU_TESS_WINDING_RULE
                      Determines  which  parts of the polygon are on the "inte‐
                      rior".  data may be set to one  of  GLU_TESS_WINDING_ODD,
                      GLU_TESS_WINDING_NONZERO,  GLU_TESS_WINDING_POSITIVE,  or
                      GLU_TESS_WINDING_NEGATIVE,                             or
                      GLU_TESS_WINDING_ABS_GEQ_TWO.

                      To  understand  how the winding rule works, consider that
                      the input contours partition the plane into regions.  The
                      winding rule determines which of these regions are inside
                      the polygon.

                      For a single contour C, the winding number of a  point  x
                      is simply the signed number of revolutions we make around
                      x as we travel once around C  (where  CCW  is  positive).
                      When  there  are several contours, the individual winding
                      numbers are summed. This procedure  associates  a  signed
                      integer  value  with each point x in the plane. Note that
                      the winding number is the same for all points in a single
                      region.

                      The  winding  rule classifies a region as "inside" if its
                      winding number belongs to the chosen category (odd,  non‐
                      zero,  positive,  negative, or absolute value of at least
                      two). The previous GLU tessellator  (prior  to  GLU  1.2)
                      used the "odd" rule. The "nonzero" rule is another common
                      way to define the interior. The  other  three  rules  are
                      useful for polygon CSG operations.

       GLU_TESS_BOUNDARY_ONLY
                      Is  a  boolean value ("value" should be set to GL_TRUE or
                      GL_FALSE). When set to GL_TRUE, a set of closed  contours
                      separating the polygon interior and exterior are returned
                      instead of a tessellation. Exterior contours are oriented
                      CCW  with  respect  to  the normal; interior contours are
                      Feature  merging is completely optional; the tolerance is
                      only a hint.  The implementation is free to merge in some
                      cases  and  not  in others, or to never merge features at
                      all. The initial tolerance is 0.

                      The current implementation merges vertices only  if  they
                      are  exactly coincident, regardless of the current toler‐
                      ance. A vertex is spliced into an edge only if the imple‐
                      mentation is unable to distinguish which side of the edge
                      the vertex lies on. Two edges are merged only  when  both
                      endpoints are identical.

SEE ALSO
       gluGetTessProperty, gluNewTess

                                                            GLUTESSPROPERTY(3G)