Static Sub BeginCurve ( Nurb As GluNurb )

Delimit a NURBS curve definition.

Parameters

nurb

Specifies the NURBS object (created with Glu.NewNurbsRenderer).

Description

Use Glu.BeginCurve to mark the beginning of a NURBS curve definition. After calling Glu.BeginCurve, make one or more calls to Glu.NurbsCurve to define the attributes of the curve. Exactly one of the calls to Glu.NurbsCurve 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 Glu.EndCurve.

GL evaluators are used to render the NURBS curve as a series of line segments. Evaluator state is preserved during rendering with Gl.PushAttrib(Glu.EVAL_BIT) and Gl.PopAttrib(). See the Gl.PushAttrib 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 original documentation on OpenGL website