gluBeginCurve()

NAME

gluBeginCurve, gluEndCurve − delimit a NURBS curve definition

SYNOPSIS

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);

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