Tao.OpenGl SDK Documentation

Glu.gluNurbsCurve Method (GLUnurbs, Int32, Single[], Int32, Single[], Int32, Int32)

Defines the shape of a NURBS curve.

[Visual Basic]
Overloads Public Shared Sub gluNurbsCurve( _
   ByVal nurb As GLUnurbs, _
   ByVal knotCount As Integer, _
   ByVal knots As Single(), _
   ByVal stride As Integer, _
   ByVal control As Single(), _
   ByVal order As Integer, _
   ByVal type As Integer _
)
[C#]
public static void gluNurbsCurve(
   GLUnurbs nurb,
   int knotCount,
   float[] knots,
   int stride,
   float[] control,
   int order,
   int type
);

Parameters

nurb
The NURBS object (created with gluNewNurbsRenderer).
knotCount
The number of knots in knot. The knotCount parameter equals the number of control points plus the order.
knots
An array of knotCount nondecreasing knot values.
stride
The offset (as a number of single precision?–floating-point values) between successive curve control points.
control
A pointer to an array of control points. The coordinates must agree with type.
order
The order of the NURBS curve. The order parameter equals degree + 1; hence a cubic curve has an order of 4.
type
The type of the curve. If this curve is defined within a gluBeginCurve/gluEndCurve pair, then the type can be any of the valid one-dimensional evaluator types (such as GL_MAP1_VERTEX_3 or GL_MAP1_COLOR_4). Between a gluBeginTrim/gluEndTrim pair, the only valid types are GLU_MAP1_TRIM_2 and GLU_MAP1_TRIM_3.

Remarks

Use gluNurbsCurve to describe a NURBS curve.

When gluNurbsCurve appears between a gluBeginCurve/gluEndCurve pair, it is used to describe a curve to be rendered. Positional, texture, and color coordinates are associated by presenting each as a separate gluNurbsCurve between a gluBeginCurve/gluEndCurve pair. No more than one call to gluNurbsCurve for each of color, position, and texture data can be made within a single gluBeginCurve/gluEndCurve pair. Exactly one call must be made to describe the position of the curve (a type of GL_MAP1_VERTEX_3 or GL_MAP1_VERTEX_4).

When gluNurbsCurve appears between a gluBeginTrim/gluEndTrim 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 gluBeginTrim reference page for more discussion about trimming curves.

NOTES

To define trim curves which stitch well, use gluPwlCurve.

EXAMPLE

The following commands render a textured NURBS curve with normals:

            Glu.gluBeginCurve(nobj);
            Glu.gluNurbsCurve(nobj, ..., Gl.GL_MAP1_TEXTURE_COORD_2);
            Glu.gluNurbsCurve(nobj, ..., Gl.GL_MAP1_NORMAL);
            Glu.gluNurbsCurve(nobj, ..., Gl.GL_MAP1_VERTEX_4);
            Glu.gluEndCurve(nobj);
            

See Also

Glu Class | Tao.OpenGl Namespace | Glu.gluNurbsCurve Overload List | gluBeginCurve | gluBeginTrim | gluEndCurve | gluEndTrim | gluNewNurbsRenderer | gluPwlCurve