gluBeginCurve

gluBeginCurve: man2/gluBeginCurve.xml

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.