Glu.NurbsCurve (gb.opengl.glu)

Static Sub NurbsCurve ( Nurb As GluNurb, KnotCount As Integer, Knots As Single[], Stride As Integer, Control As Single[], Order As Integer, Type As Integer )

Define the shape of a NURBS curve.



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

Specifies the number of knots in knots. knotCount equals the number of control points plus the order.

Specifies an array of knotCount nondecreasing knot values.

Specifies the offset (as a number of single-precision floating-point values) between successive curve control points.

Specifies a pointer to an array of control points. The coordinates must agree with type, specified below.

Specifies the order of the NURBS curve. order equals degree + 1, hence a cubic curve has an order of 4.

Specifies the type of the curve. If this curve is defined within a Glu.BeginCurve/Glu.EndCurve pair, then the type can be any of the valid one-dimensional evaluator types (such as Glu.MAP1_VERTEX_3 or Glu.MAP1_COLOR_4). Between a Glu.BeginTrim/Glu.EndTrim pair, the only valid types are Glu.MAP1_TRIM_2 and Glu.MAP1_TRIM_3.


Use Glu.NurbsCurve to describe a NURBS curve.

When Glu.NurbsCurve appears between a Glu.BeginCurve/Glu.EndCurve pair, it is used to describe a curve to be rendered. Positional, texture, and color coordinates are associated by presenting each as a separate Glu.NurbsCurve between a Glu.BeginCurve/Glu.EndCurve pair. No more than one call to Glu.NurbsCurve for each of color, position, and texture data can be made within a single Glu.BeginCurve/Glu.EndCurve pair. Exactly one call must be made to describe the position of the curve (a type of Glu.MAP1_VERTEX_3 or Glu.MAP1_VERTEX_4).

When Glu.NurbsCurve appears between a Glu.BeginTrim/Glu.EndTrim pair, it is used to describe a trimming curve on a NURBS surface. If type is Glu.MAP1_TRIM_2, then it describes a curve in two-dimensional (u and v) parameter space. If it is Glu.MAP1_TRIM_3, then it describes a curve in two-dimensional homogeneous (u, v, and w) parameter space. See the Glu.BeginTrim reference page for more discussion about trimming curves.


The following commands render a textured NURBS curve with normals:
gluNurbsCurve(nobj, ..., GL_MAP1_TEXTURE_COORD_2);
gluNurbsCurve(nobj, ..., GL_MAP1_NORMAL);
gluNurbsCurve(nobj, ..., GL_MAP1_VERTEX_4);


To define trim curves that stitch well, use Glu.PwlCurve.

See also

Glu.BeginCurve, Glu.BeginTrim, Glu.PwlCurve

See original documentation on OpenGL website