gluNurbsSurface

gluNurbsSurface: define the shape of a NURBS surface.

C Specification | Parameters | Description | See Also

C Specification

void gluNurbsSurface(
    GLUnurbs*	 nurb,
    GLint	 sKnotCount,
    GLfloat*	 sKnots,
    GLint	 tKnotCount,
    GLfloat*	 tKnots,
    GLint	 sStride,
    GLint	 tStride,
    GLfloat*	 control,
    GLint	 sOrder,
    GLint	 tOrder,
    GLenum	 type)

Parameters

nurb: Specifies the NURBS object (created with gluNewNurbsRenderer).
sKnotCount: Specifies the number of knots in the parametric u direction.
sKnots: Specifies an array of sKnotCount nondecreasing knot values in the parametric u direction.
tKnotCount: Specifies the number of knots in the parametric v direction.
tKnots: Specifies an array of tKnotCount nondecreasing knot values in the parametric v direction.
sStride: Specifies the offset (as a number of single-precision floating point values) between successive control points in the parametric u direction in control.
tStride: Specifies the offset (in single-precision floating-point values) between successive control points in the parametric v direction in control.
control: Specifies 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 sStride and tStride.
sOrder: Specifies 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: Specifies 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: Specifies type of the surface. type can be any of the valid two-dimensional evaluator types (such as GL_MAP2_VERTEX_3 or GL_MAP2_COLOR_4).

Use gluNurbsSurface within a NURBS (Non-Uniform Rational B-Spline) 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 command. To mark the end of a NURBS surface definition, use the gluEndSurface command. Call gluNurbsSurface within a NURBS surface definition only.

Positional, texture, and color coordinates are associated with a surface by presenting each as a separate gluNurbsSurface between a gluBeginSurface/gluEndSurface pair. No more than one call to gluNurbsSurface for each of color, position, and texture data can be made within a single gluBeginSurface/gluEndSurface pair. Exactly one call must be made to describe the position of the surface (a type of GL_MAP2_VERTEX_3 or GL_MAP2_VERTEX_4).

A NURBS surface can be trimmed by using the commands gluNurbsCurve and gluPwlCurve between calls to gluBeginTrim and gluEndTrim.

Note that a gluNurbsSurface with sKnotCount knots in the u direction and tKnotCount knots in the v direction with orders sOrder and tOrder must have (sKnotCount sOrder) (tKnotCount tOrder) control points.