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GLUNURBSSURFACE()                                            GLUNURBSSURFACE()

NAME
       gluNurbsSurface - define the shape of a NURBS surface

C SPECIFICATION
       void gluNurbsSurface( GLUnurbs* nurb,
                             GLint sKnotCount,
                             GLfloat* sKnots,
                             GLint tKnotCount,
                             GLfloat* tKnots,
                             GLint sStride,
                             GLint tStride,
                             GLfloat* control,
                             GLint sOrder,
                             GLint tOrder,
                             GLenum type )

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

       sKnotCount  Specifies the number of knots in the parametric u
                   direction.

       sKnots      Specifies an array of sKnotCount nondecreasing knot values
                   in the parametric u direction.

       tKnotCount  Specifies the number of knots in the parametric v
                   direction.

       tKnots      Specifies an array of tKnotCount nondecreasing knot values
                   in the parametric v direction.

       sStride     Specifies the offset (as a number of single-precision
                   floating point values) between successive control points in
                   the parametric u direction in control.

       tStride     Specifies the offset (in single-precision floating-point
                   values) between successive control points in the parametric
                   v direction in control.

       control     Specifies an array containing control points for the NURBS
                   surface.  The offsets between successive control points in
                   the parametric u and v directions are given by sStride and
                   tStride.

       sOrder      Specifies the order of the NURBS surface in the parametric
                   u direction. The order is one more than the degree, hence a
                   surface that is cubic in u has a u order of 4.

       tOrder      Specifies the order of the NURBS surface in the parametric
                   v direction. The order is one more than the degree, hence a
                   surface that is cubic in v has a v order of 4.

       type        Specifies type of the surface. type can be any of the valid
                   two-dimensional evaluator types (such as GL_MAP2_VERTEX_3
                   or GL_MAP2_COLOR_4).

DESCRIPTION
       Use gluNurbsSurface within a NURBS (Non-Uniform Rational B-Spline)
       surface definition to describe the shape of a NURBS surface (before any
       trimming). To mark the beginning of a NURBS surface definition, use the
       gluBeginSurface command.  To mark the end of a NURBS surface
       definition, use the gluEndSurface command. Call gluNurbsSurface within
       a NURBS surface definition only.

       Positional, texture, and color coordinates are associated with a
       surface by presenting each as a separate gluNurbsSurface between a
       gluBeginSurface/gluEndSurface pair. No more than one call to
       gluNurbsSurface for each of color, position, and texture data can be
       made within a single gluBeginSurface/gluEndSurface pair. Exactly one
       call must be made to describe the position of the surface (a type of
       GL_MAP2_VERTEX_3 or GL_MAP2_VERTEX_4).

       A NURBS surface can be trimmed by using the commands gluNurbsCurve and
       gluPwlCurve between calls to gluBeginTrim and gluEndTrim.

       Note that a gluNurbsSurface with sKnotCount knots in the u direction
       and tKnotCount knots in the v direction with orders sOrder and tOrder
       must have (sKnotCount - sOrder) x (tKnotCount - tOrder) control points.

EXAMPLE
       The following commands render a textured NURBS surface with normals;
       the texture coordinates and normals are also NURBS surfaces:

       gluBeginSurface(nobj);
          gluNurbsSurface(nobj, ..., GL_MAP2_TEXTURE_COORD_2);
          gluNurbsSurface(nobj, ..., GL_MAP2_NORMAL);
          gluNurbsSurface(nobj, ..., GL_MAP2_VERTEX_4); gluEndSurface(nobj);

SEE ALSO
       gluBeginSurface, gluBeginTrim, gluNewNurbsRenderer, gluNurbsCurve,
       gluPwlCurve

                                                             GLUNURBSSURFACE()