glupwlcurve(3g) [centos man page]

GLUPWLCURVE(3G) 						   OpenGL Manual						   GLUPWLCURVE(3G)

NAME

       gluPwlCurve - describe a piecewise linear NURBS trimming curve

C SPECIFICATION

       void gluPwlCurve(GLUnurbs* nurb, GLint count, GLfloat* data, GLint stride, GLenum type);

PARAMETERS

       nurb
	   Specifies the NURBS object (created with gluNewNurbsRenderer()).

       count
	   Specifies the number of points on the curve.

       data
	   Specifies an array containing the curve points.

       stride
	   Specifies the offset (a number of single-precision floating-point values) between points on the curve.

       type
	   Specifies the type of curve. Must be either GLU_MAP1_TRIM_2 or GLU_MAP1_TRIM_3.

DESCRIPTION

       gluPwlCurve describes a piecewise linear trimming curve for a NURBS surface. A piecewise linear curve consists of a list of coordinates of
       points in the parameter space for the NURBS surface to be trimmed. These points are connected with line segments to form a curve. If the
       curve is an approximation to a curve that is not piecewise linear, the points should be close enough in parameter space that the resulting
       path appears curved at the resolution used in the application.

       If type is GLU_MAP1_TRIM_2, then it describes a curve in two-dimensional (u and v) parameter space. If it is GLU_MAP1_TRIM_3, then it
       describes a curve in two-dimensional homogeneous (u, v, and w) parameter space. See the gluBeginTrim() reference page for more information
       about trimming curves.

NOTES

       To describe a trim curve that closely follows the contours of a NURBS surface, call gluNurbsCurve().

SEE ALSO

       gluBeginCurve(), gluBeginTrim(), gluNewNurbsRenderer(), gluNurbsCurve()

COPYRIGHT

       Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see
       http://oss.sgi.com/projects/FreeB/.

AUTHORS

       opengl.org

opengl.org							    06/10/2014							   GLUPWLCURVE(3G)

GLUNURBSCURVE(3G)														 GLUNURBSCURVE(3G)

NAME

       gluNurbsCurve - define the shape of a NURBS curve

C SPECIFICATION

       void gluNurbsCurve( GLUnurbs* nurb,
			   GLint knotCount,
			   GLfloat *knots,
			   GLint stride,
			   GLfloat *control,
			   GLint order,
			   GLenum type )

PARAMETERS

       nurb	  Specifies the NURBS object (created with gluNewNurbsRenderer).

       knotCount  Specifies the number of knots in knots.  knotCount equals the number of control points plus the order.

       knots	  Specifies an array of knotCount nondecreasing knot values.

       stride	  Specifies the offset (as a number of single-precision floating-point values) between successive curve control points.

       control	  Specifies a pointer to an array of control points. The coordinates must agree with type, specified below.

       order	  Specifies the order of the NURBS curve. order equals degree + 1, hence a cubic curve has an order of 4.

       type	  Specifies  the  type of the curve. If this curve is defined within a gluBeginCurve/gluEndCurve pair, then the type can be any of
		  the valid one-dimensional evaluator types (such as GL_MAP1_VERTEX_3 or GL_MAP1_COLOR_4). Between a gluBeginTrim/gluEndTrim pair,
		  the only valid types are GLU_MAP1_TRIM_2 and GLU_MAP1_TRIM_3.

DESCRIPTION

       Use gluNurbsCurve to describe a NURBS curve.

       When  gluNurbsCurve  appears between a gluBeginCurve/gluEndCurve pair, it is used to describe a curve to be rendered.  Positional, texture,
       and color coordinates are associated by presenting each as a separate gluNurbsCurve between a gluBeginCurve/gluEndCurve pair. No more  than
       one call to gluNurbsCurve for each of color, position, and texture data can be made within a single gluBeginCurve/gluEndCurve pair. Exactly
       one call must be made to describe the position of the curve (a type of GL_MAP1_VERTEX_3 or GL_MAP1_VERTEX_4).

       When gluNurbsCurve appears between a gluBeginTrim/gluEndTrim pair, it is used to describe a trimming curve on a NURBS surface. If  type	is
       GLU_MAP1_TRIM_2,  then  it  describes  a  curve in two-dimensional (u and v) parameter space. If it is GLU_MAP1_TRIM_3, then it describes a
       curve in two-dimensional homogeneous (u, v, and w) parameter space.  See the gluBeginTrim reference page for more discussion about trimming
       curves.

EXAMPLE

       The following commands render a textured NURBS curve with normals:

       gluBeginCurve(nobj);
	  gluNurbsCurve(nobj, ..., GL_MAP1_TEXTURE_COORD_2);
	  gluNurbsCurve(nobj, ..., GL_MAP1_NORMAL);
	  gluNurbsCurve(nobj, ..., GL_MAP1_VERTEX_4); gluEndCurve(nobj);

NOTES

       To define trim curves which stitch well, use gluPwlCurve.

SEE ALSO

       gluBeginCurve(3G), gluBeginTrim(3G), gluNewNurbsRenderer(3G), gluPwlCurve(3G)

																 GLUNURBSCURVE(3G)