Glu.BeginCurve (gb.opengl.glu)
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 also
Glu.NurbsCurve,
Gl.PopAttrib,
Gl.PushAttrib