GLUNURBSSURFACE



GLUNURBSSURFACE

NAME
C SPECIFICATION
PARAMETERS
DESCRIPTION
EXAMPLE
SEE ALSO

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)






Opportunity


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.





Free Software


Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.


Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.





Free Books


The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.


Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.





Education


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.


Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.