gluNurbsSurface()gluNurbsSurface()NAMEgluNurbsSurface - define the shape of a NURBS surface
SYNOPSIS
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
Specifies the NURBS object (created with gluNewNurbsRenderer()). Spec‐
ifies the number of knots in the parametric u direction. Specifies an
array of sKnotCount nondecreasing knot values in the parametric u
direction. Specifies the number of knots in the parametric v direc‐
tion. Specifies an array of tKnotCount nondecreasing knot values in
the parametric v direction. Specifies the offset (as a number of sin‐
gle-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. 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. 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).
DESCRIPTION
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 defini‐
tion, use the gluEndSurface() command. Call gluNurbsSurface() within a
NURBS surface definition only.
Positional, texture, and color coordinates are associated with a sur‐
face 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.
EXAMPLE
The following commands render a textured NURBS surface with normals;
the texture coordinates and normals are also NURBS surfaces: gluBegin‐
Surface(nobj);
gluNurbsSurface(nobj, ..., GL_MAP2_TEXTURE_COORD_2);
gluNurbsSurface(nobj, ..., GL_MAP2_NORMAL);
gluNurbsSurface(nobj, ..., GL_MAP2_VERTEX_4); gluEndSurface(nobj);
SEE ALSOgluBeginSurface(3), gluBeginTrim(3), gluNewNurbsRenderer(3), gluNurb‐
sCurve(3), gluPwlCurve(3)gluNurbsSurface()
