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GLUBEGINSURFACE()                                            GLUBEGINSURFACE()

NAME
       gluBeginSurface, gluEndSurface - delimit a NURBS surface definition

C SPECIFICATION
       void gluBeginSurface( GLUnurbs* nurb )

       void gluEndSurface( GLUnurbs* nurb )

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

DESCRIPTION
       Use gluBeginSurface to mark the beginning of a NURBS surface
       definition. After calling gluBeginSurface, make one or more calls to
       gluNurbsSurface to define the attributes of the surface.  Exactly one
       of these calls to gluNurbsSurface must have a surface type of
       GL_MAP2_VERTEX_3 or GL_MAP2_VERTEX_4.  To mark the end of the NURBS
       surface definition, call gluEndSurface.

       Trimming of NURBS surfaces is supported with gluBeginTrim, gluPwlCurve,
       gluNurbsCurve, and gluEndTrim. See the gluBeginTrim reference page for
       details.

       GL evaluators are used to render the NURBS surface as a set of
       polygons.  Evaluator state is preserved during rendering with
       glPushAttrib(GL_EVAL_BIT) and glPopAttrib().  See the glPushAttrib
       reference page for details on exactly what state these calls preserve.

EXAMPLE
       The following commands render a textured NURBS surface with normals;
       the texture coordinates and normals are also described as 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
       gluBeginCurve, gluBeginTrim, gluNewNurbsRenderer, gluNurbsCurve,
       gluNurbsSurface, gluPwlCurve

                                                             GLUBEGINSURFACE()