GLUBEGINCURVE(3G)

NAME
gluBeginCurve - delimit a NURBS curve definition

C SPECIFICATION

void gluBeginCurve(GLUnurbs* nurb);

C SPECIFICATION

void gluEndCurve(GLUnurbs* nurb);

PARAMETERS

nurb
    Specifies the NURBS object (created with gluNewNurbsRenderer()).

DESCRIPTION

Use gluBeginCurve to mark the beginning of a NURBS curve definition. After calling gluBeginCurve, make one or more calls to gluNurbsCurve() to define the attributes of the curve. Exactly one of the calls to gluNurbsCurve() must have a curve type of GLU_MAP1_VERTEX_3 or GLU_MAP1_VERTEX_4. To mark the end of the NURBS curve definition, call gluEndCurve().

GL evaluators are used to render the NURBS curve as a series of line segments. 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 curve with normals; texture coordinates and normals are also specified as NURBS curves:

    gluBeginCurve(nobj);
       gluNurbsCurve(nobj, ..., GL_MAP1_TEXTURE_COORD_2);
       gluNurbsCurve(nobj, ..., GL_MAP1_NORMAL);
       gluNurbsCurve(nobj, ..., GL_MAP1_VERTEX_4);
    gluEndCurve(nobj);

SEE ALSO

gluBeginSurface(), gluBeginTrim(), gluNewNurbsRenderer(), gluNurbsCurve(), glPopAttrib(), 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/.

AUTHORS

opengl.org