Table of Contents
gluNurbsSurface - define the shape of a NURBS surface
gluNurbsSurface( GLUnurbs* nurb,
GLenum type )
eqn not supported
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
- Specifies the NURBS object (created with
- Specifies the number of knots in the parametric
- Specifies an array of sKnotCount nondecreasing knot
values in the parametric u direction.
- Specifies the number of
knots in the parametric v direction.
- Specifies an array of tKnotCount
nondecreasing knot values in the parametric v direction.
the offset (as a number of single-precision floating point values) between
successive control points in the parametric u direction in control.
- Specifies the offset (in single-precision floating-point values) between
successive control points in the parametric v direction in 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.
- 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.
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.
- 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).
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)
$times$ (tKnotCount - tOrder) control points.
The following commands
render a textured NURBS surface with normals; the texture coordinates and
normals are also NURBS surfaces:
gluNurbsSurface(nobj, ..., GL_MAP2_NORMAL);
gluNurbsSurface(nobj, ..., GL_MAP2_VERTEX_4);
Table of Contents