gluNurbsSurface function

Article
12/11/2020

The gluNurbsSurface function defines the shape of a Non-Uniform Rational B-Spline (NURBS) surface.

Syntax

void WINAPI gluNurbsSurface(
   GLUnurbs *nobj,
   GLint    sknot_count,
   float    *sknot,
   GLint    tknot_count,
   GLfloat  *tknot,
   GLint    s_stride,
   GLint    t_stride,
   GLfloat  *ctlarray,
   GLint    sorder,
   GLint    torder,
   GLenum   type
);

Parameters

nobj: The NURBS object (created with gluNewNurbsRenderer).
sknot_count: The number of knots in the parametric u direction.
sknot: An array of sknot_count nondecreasing knot values in the parametric u direction.
tknot_count: The number of knots in the parametric v direction.
tknot: An array of tknot_count nondecreasing knot values in the parametric v direction.
s_stride: The offset (as a number of single precisionfloating-point values) between successive control points in the parametric u direction in ctlarray.
t_stride: The offset (in single precisionfloating-point values) between successive control points in the parametric v direction in ctlarray.
ctlarray: An array containing control points for the NURBS surface. The offsets between successive control points in the parametric u and v directions are given by s_stride and t_stride.
sorder: The order of the NURBS surface in the parametric u direction. The order is one more than the degree, hence a surface that is cubic in u has a u order of 4.
torder: The order of the NURBS surface in the parametric v direction. The order is one more than the degree, hence a surface that is cubic in v has a v order of 4.
type: The type of the surface. The type parameter can be any of the valid two-dimensional evaluator types (such as GL_MAP2_VERTEX_3 or GL_MAP2_COLOR_4).

Return value

This function does not return a value.

Remarks

Use gluNurbsSurface within a NURBS surface definition to describe the shape of a NURBS surface (before any trimming). To mark the beginning of a NURBS surface definition, use the gluBeginSurface function. To mark the end of a NURBS surface definition, use the gluEndSurface function. Call gluNurbsSurface within a NURBS surface definition only.

You associate positional, texture, and color coordinates with a surface by presenting each as a separate gluNurbsSurface between a gluBeginSurface/gluEndSurface pair. Within a single gluBeginSurface/gluEndSurface pair, you can make only one call to gluNurbsSurface for color, position, and texture data. Make exactly one call to describe the position of the surface (a type of GL_MAP2_VERTEX_3 or GL_MAP2_VERTEX_4).

You can trim a NURBS surface by using the gluNurbsCurve and gluPwlCurve functions between calls to gluBeginTrim and gluEndTrim.

A gluNurbsSurface with sknot_count knots in the u direction and tknot_count knots in the v direction with orders sorder and torder must have (sknot_count -sorder) multipied by (tknot_count -torder) control points.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Header	Glu.h
Library	Glu32.lib
DLL	Glu32.dll