GLUBEGINSURFACE(3G)

NAME
gluBeginSurface - delimit a NURBS surface definition

C SPECIFICATION

void gluBeginSurface(GLUnurbs* nurb);

C SPECIFICATION

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 GLU_MAP2_VERTEX_3 or GLU_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()(GLU_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(), glPushAttrib()

COPYRIGHT

Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.