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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  suc-cessive successive
                  cessive 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 gluBeginCurve/gluEndCurve
                  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 homo-geneous homogeneous
       geneous (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)