glunurbscurve(3G) — IRIX 6.5.3f



gluNurbsCurve(3G)              OpenGL Reference              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
                GLMAP1VERTEX3 or GLMAP1COLOR4).  Between a
                gluBeginTrim/gluEndTrim pair, the only valid types are
                GLUMAP1TRIM2 and GLUMAP1TRIM3.


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
     GLMAP1VERTEX3 or GLMAP1VERTEX4).




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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
     GLUMAP1TRIM2, then it describes a curve in two-dimensional (u and v)
     parameter space.  If it is GLUMAP1TRIM3, 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 which stitch well use gluPwlCurve.


SEE ALSO
     gluBeginCurve, gluBeginTrim, gluNewNurbsRenderer, gluPwlCurve





























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