gluNurbsSurface()                               gluNurbsSurface()

NAME    [Toc]    [Back]

       gluNurbsSurface - define the shape of a NURBS surface

SYNOPSIS    [Toc]    [Back]

       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    [Toc]    [Back]

       Specifies  the  NURBS object (created with gluNewNurbsRenderer()).
  Specifies the number of knots in the parametric
       u direction.  Specifies an array of sKnotCount nondecreasing
 knot values in the parametric u direction.   Specifies
       the number of knots in the parametric v direction.  Specifies
 an array of tKnotCount nondecreasing knot  values  in
       the  parametric  v  direction.  Specifies the offset (as a
       number of single-precision floating point values)  between
       successive control points in the parametric u direction in
       control.  Specifies the offset (in single-precision floating-point
 values) between successive control points in the
       parametric v direction in  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.  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.   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.  Specifies
       type of the surface.  type can be any of  the  valid  twodimensional
  evaluator  types (such as GL_MAP2_VERTEX_3 or
       GL_MAP2_COLOR_4).

DESCRIPTION    [Toc]    [Back]

       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)
       $times$ (tKnotCount - tOrder) control points.

EXAMPLE    [Toc]    [Back]

       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    [Toc]    [Back]

       gluBeginSurface(3),    gluBeginTrim(3),    gluNewNurbsRenderer(3), gluNurbsCurve(3), gluPwlCurve(3)



                                                gluNurbsSurface()