fgluBeginSurface(3G)

NAME
     fgluBeginSurface, fgluEndSurface - delimit a NURBS surface definition


FORTRAN SPECIFICATION
     SUBROUTINE fgluBeginSurface( CHARACTER*8 nurb )

     SUBROUTINE fgluEndSurface( CHARACTER*8 nurb )


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

DESCRIPTION
     Use fgluBeginSurface to mark the beginning of a NURBS surface definition.
     After calling fgluBeginSurface, make one or more calls to
     fgluNurbsSurface to define the attributes of the surface.  Exactly one of
     these calls to fgluNurbsSurface 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 fgluEndSurface.

     Trimming of NURBS surfaces is supported with fgluBeginTrim, fgluPwlCurve,
     fgluNurbsCurve, and fgluEndTrim. See the fgluBeginTrim 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
     fgluBeginCurve, fgluBeginTrim, fgluNewNurbsRenderer, fgluNurbsCurve,
     fgluNurbsSurface, fgluPwlCurve