gluNurbsCurve(3G)	       OpenGL Reference		     gluNurbsCurve(3G)

NAME    [Toc]    [Back]

     gluNurbsCurve - define the	shape of a NURBS curve

C SPECIFICATION    [Toc]    [Back]

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

PARAMETERS    [Toc]    [Back]

     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    [Toc]    [Back]

     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).





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gluNurbsCurve(3G)	       OpenGL Reference		     gluNurbsCurve(3G)



     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    [Toc]    [Back]

     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    [Toc]    [Back]

     To	define trim curves which stitch	well, use gluPwlCurve.

SEE ALSO    [Toc]    [Back]

     gluBeginCurve, gluBeginTrim, gluNewNurbsRenderer, gluPwlCurve


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