gluNurbsCurve	- define the shape of a	NURBS curve

	  void gluNurbsCurve( GLUnurbs*	nurb,
			      GLint knotCount,
			      GLfloat *knots,
			      GLint stride,
			      GLfloat *control,
			      GLint order,
			      GLenum type )

	  nurb	     Specifies the NURBS object	(created with

	  knotCount  Specifies the number of knots in knots.
		     knotCount equals the number of control points
		     plus the order.

	  knots	     Specifies an array	of knotCount nondecreasing
		     knot values.

	  stride     Specifies the offset (as a	number of single-
		     precision floating-point values) between
		     successive	curve control points.

	  control    Specifies a pointer to an array of	control
		     points. The coordinates must agree	with type,
		     specified below.

	  order	     Specifies the order of the	NURBS curve. order
		     equals degree + 1,	hence a	cubic curve has	an
		     order of 4.

	  type	     Specifies the type	of the curve. If this curve is
		     defined within a gluBeginCurve/gluEndCurve	pair,
		     then the type can be any of the valid one-
		     dimensional evaluator types (such as
		     GL_MAP1_VERTEX_3 or GL_MAP1_COLOR_4). Between a
		     gluBeginTrim/gluEndTrim pair, the only valid
		     types are GLU_MAP1_TRIM_2 and GLU_MAP1_TRIM_3.

	  Use gluNurbsCurve to describe	a NURBS	curve.

	  When gluNurbsCurve appears between a
	  gluBeginCurve/gluEndCurve pair, it is	used to	describe a
	  curve	to be rendered.	 Positional, texture, and color
	  coordinates are associated by	presenting each	as a separate
	  gluNurbsCurve	between	a gluBeginCurve/gluEndCurve pair. No
	  more than one	call to	gluNurbsCurve for each of color,
	  position, and	texture	data can be made within	a single
	  gluBeginCurve/gluEndCurve pair. Exactly one call must	be
	  made to describe the position	of the curve (a	type of

	  When gluNurbsCurve appears between a gluBeginTrim/gluEndTrim
	  pair,	it is used to describe a trimming curve	on a NURBS
	  surface. If type is GLU_MAP1_TRIM_2, then it describes a
	  curve	in two-dimensional (u and v) parameter space. If it is
	  GLU_MAP1_TRIM_3, then	it describes a curve in	two-
	  dimensional homogeneous (u, v, and w)	parameter space.  See
	  the gluBeginTrim reference page for more discussion about
	  trimming curves.

	  The following	commands render	a textured NURBS curve with

	     gluNurbsCurve(nobj, ..., GL_MAP1_TEXTURE_COORD_2);
	     gluNurbsCurve(nobj, ..., GL_MAP1_NORMAL);
	     gluNurbsCurve(nobj, ..., GL_MAP1_VERTEX_4);

	  To define trim curves	which stitch well, use gluPwlCurve.

	  gluBeginCurve, gluBeginTrim, gluNewNurbsRenderer,