gluNurbsCurve()                                   gluNurbsCurve()

NAME    [Toc]    [Back]

       gluNurbsCurve - define the shape of a NURBS curve

SYNOPSIS    [Toc]    [Back]

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

PARAMETERS    [Toc]    [Back]

       Specifies  the  NURBS object (created with gluNewNurbsRenderer()).
  Specifies the number of knots in knots.   knotCount
  equals the number of control points plus the order.
       Specifies an array of knotCount nondecreasing knot values.
       Specifies  the  offset  (as  a  number of single-precision
       floating-point values) between  successive  curve  control
       points.   Specifies  a  pointer  to  an  array  of control
       points. The coordinates must agree  with  type,  specified
       below.   Specifies  the  order  of the NURBS curve.  order
       equals degree + 1, hence a cubic curve has an order of  4.
       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).

       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.

NOTES    [Toc]    [Back]

       To define trim  curves  which  stitch  well,  use  gluPwlCurve().

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);

SEE ALSO    [Toc]    [Back]

       gluBeginCurve(3), gluBeginTrim(3), gluNewNurbsRenderer(3),
       gluPwlCurve(3),



                                                  gluNurbsCurve()