gluBeginSurface(3G)	       OpenGL Reference		   gluBeginSurface(3G)

NAME    [Toc]    [Back]

     gluBeginSurface, gluEndSurface - delimit a	NURBS surface definition

C SPECIFICATION    [Toc]    [Back]

     void gluBeginSurface( GLUnurbs* nurb )

     void gluEndSurface( GLUnurbs* nurb	)

PARAMETERS    [Toc]    [Back]

     nurb  Specifies the NURBS object (created with gluNewNurbsRenderer).

DESCRIPTION    [Toc]    [Back]

     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    [Toc]    [Back]

     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    [Toc]    [Back]

     gluBeginCurve, gluBeginTrim, gluNewNurbsRenderer, gluNurbsCurve,
     gluNurbsSurface, gluPwlCurve


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