NAME
	  fgluTessProperty - set a tessellation	object property


     FORTRAN SPECIFICATION
	  SUBROUTINE fgluTessProperty( CHARACTER*8 tess,
				       INTEGER*4 which,
				       REAL*8 data )


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

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

	  GLU_TESS_WINDING_RULE
			 Determines which parts	of the polygon are on
			 the "interior". 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, nonzero,	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 oriented	CW. The
			 GLU_TESS_BEGIN	and GLU_TESS_BEGIN_DATA
			 callbacks use the type	GL_LINE_LOOP for each
			 contour.

	  GLU_TESS_TOLERANCE
			 Specifies a tolerance for merging features to
			 reduce	the size of the	output.	 For example,
			 two vertices that are very close to each
			 other might be	replaced by a single vertex.
			 The tolerance is multiplied by	the largest
			 coordinate magnitude of any input vertex;
			 this specifies	the maximum distance that any
			 feature can move as the result	of a single
			 merge operation. If a single feature takes
			 part in several merge operations, the total
			 distance moved	could be larger.

			 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 tolerance. A	vertex
			 is spliced into an edge only if the
			 implementation	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
	  fgluGetTessProperty