GLUBEGINSURFACE(3G)GLUBEGINSURFACE(3G)NAME
gluBeginSurface, gluEndSurface - delimit a NURBS surface definition
C SPECIFICATION
void gluBeginSurface( GLUnurbs* nurb )
void gluEndSurface( GLUnurbs* nurb )
delim $$
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 ALSOgluBeginCurve(3G), gluBeginTrim(3G), gluNewNurbsRenderer(3G),
gluNurbsCurve(3G), gluNurbsSurface(3G), gluPwlCurve(3G)
March 1, 2011
