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Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :

ISBN : 978-2-7460-9712-4
EAN : 9782746097124
(Editions ENI)

GNU/Linux	CentOS 5.3
	gluNurbsSurface(3gl)

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GLUNURBSSURFACE

NAME
C SPECIFICATION
PARAMETERS
DESCRIPTION
EXAMPLE
SEE ALSO

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NAME

gluNurbsSurface − define the shape of a NURBS surface

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).

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 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) $times$ (tKnotCount - tOrder) control points.

EXAMPLE

The following commands render a textured NURBS surface with normals; the texture coordinates and normals are also NURBS surfaces:

gluBeginSurface(nobj);
gluNurbsSurface(nobj, ..., GL_MAP2_TEXTURE_COORD_2);
gluNurbsSurface(nobj, ..., GL_MAP2_NORMAL);
gluNurbsSurface(nobj, ..., GL_MAP2_VERTEX_4); gluEndSurface(nobj);

SEE ALSO

gluBeginSurface(3G), gluBeginTrim(3G), gluNewNurbsRenderer(3G), gluNurbsCurve(3G), gluPwlCurve(3G)

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gluNurbsSurface(3gl)