gluNurbsCurve

GLUNURBSCURVE(3G)					    GLUNURBSCURVE(3G)



NAME
       gluNurbsCurve - define the shape of a NURBS curve


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


PARAMETERS
       nurb	  Specifies	the	NURBS	  object     (created	 with
		  gluNewNurbsRenderer).

       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.

DESCRIPTION
       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 GL_MAP1_VERTEX_3 or GL_MAP1_VERTEX_4).

       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.

EXAMPLE
       The following commands render a textured NURBS curve with normals:

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


NOTES
       To define trim curves which stitch well, use gluPwlCurve.

SEE ALSO
       gluBeginCurve(3G),     gluBeginTrim(3G),	     gluNewNurbsRenderer(3G),
       gluPwlCurve(3G)




							    GLUNURBSCURVE(3G)