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