GLUBEGINCURVE()

NAME

gluBeginCurve, gluEndCurve − delimit a NURBS curve definition

C SPECIFICATION

void gluBeginCurve( GLUnurbs∗ nurb )

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 GL_MAP1_VERTEX_3 or GL_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(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 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);