fgluNurbsCurve(3G)

NAME
     fgluNurbsCurve - define the shape of a NURBS curve


FORTRAN SPECIFICATION
     SUBROUTINE fgluNurbsCurve( CHARACTER*8 nurb,
                                INTEGER*4 knotCount,
                                CHARACTER*8 knots,
                                INTEGER*4 stride,
                                CHARACTER*8 control,
                                INTEGER*4 order,
                                INTEGER*4 type )


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

     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 fgluBeginCurve/fgluEndCurve 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
                fgluBeginTrim/fgluEndTrim pair, the only valid types are
                GLU_MAP1_TRIM_2 and GLU_MAP1_TRIM_3.


DESCRIPTION
     Use fgluNurbsCurve to describe a NURBS curve.

     When fgluNurbsCurve appears between a fgluBeginCurve/fgluEndCurve pair,
     it is used to describe a curve to be rendered.  Positional, texture, and
     color coordinates are associated by presenting each as a separate
     fgluNurbsCurve between a fgluBeginCurve/fgluEndCurve pair.  No more than
     one call to fgluNurbsCurve for each of color, position, and texture data
     can be made within a single fgluBeginCurve/fgluEndCurve 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 fgluNurbsCurve appears between a fgluBeginTrim/fgluEndTrim 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
     fgluBeginTrim 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 fgluPwlCurve.


SEE ALSO
     fgluBeginCurve, fgluBeginTrim, fgluNewNurbsRenderer, fgluPwlCurve