gluNurbsCurve function
The gluNurbsCurve function defines the shape of a Non-Uniform Rational B-Spline (NURBS) curve.
Syntax
void WINAPI gluNurbsCurve(
GLUnurbs *nobj,
GLint nknots,
GLfloat *knot,
GLint stride,
GLfloat *ctlarray,
GLint order,
GLenum type
);
Parameters
-
nobj
-
The NURBS object (created with gluNewNurbsRenderer).
-
nknots
-
The number of knots in knot. The nknots parameter equals the number of control points plus the order.
-
knot
-
An array of nknots nondecreasing knot values.
-
stride
-
The offset (as a number of single-precision floating-point values) between successive curve control points.
-
ctlarray
-
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.
Return value
This function does not return a value.
Remarks
When gluNurbsCurve appears between a gluBeginCurve/gluEndCurve pair, it describes a curve to be rendered. You associate positional, texture, and color coordinates by presenting each as a separate gluNurbsCurve between a gluBeginCurve/gluEndCurve pair. Do not make more than one call to gluNurbsCurve for color, position, and texture data within a single gluBeginCurve/gluEndCurve pair. Make exactly one call 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 describes a trimming curve on a NURBS surface. If type is GLU_MAP1_TRIM_2, it describes a curve in two-dimensional (u and v) parameter space. If it is GLU_MAP1_TRIM_3, it describes a curve in two-dimensional homogeneous (u, v, and w) parameter space. For more discussion about trimming curves, see gluBeginTrim.
Examples
The following functions render a textured NURBS curve with normals:
gluBeginCurve(nobj);
gluNurbsCurve(nobj, ..., GL_MAP1_TEXTURE_COORD_2);
gluNurbsCurve(nobj, ..., GL_MAP1_NORMAL);
gluNurbsCurve(nobj, ..., GL_MAP1_VERTEX_4);
gluEndCurve(nobj);
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client |
Windows 2000 Professional [desktop apps only] |
| Minimum supported server |
Windows 2000 Server [desktop apps only] |
| Header |
|
| Library |
|
| DLL |
|