GLUNURBSCURVE(3G)						   OpenGL Manual						 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 GLU_MAP1_VERTEX_3 or GLU_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 GLU_MAP1_VERTEX_3 or
       GLU_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 that stitch well, use gluPwlCurve().

SEE ALSO

       gluBeginCurve(), gluBeginTrim(), gluNewNurbsRenderer(), gluPwlCurve()

COPYRIGHT

       Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see
       http://oss.sgi.com/projects/FreeB/.

AUTHORS

       opengl.org

opengl.org							    06/10/2014							 GLUNURBSCURVE(3G)