glunurbssurface(3g) [suse man page]

GLUNURBSSURFACE(3G)													       GLUNURBSSURFACE(3G)

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 paramet-
		   ric u direction in control.

       tStride	   Specifies the offset (in single-precision floating-point values) between successive control points in the parametric  v  direc-
		   tion in control.

       control	   Specifies an array containing control points for the NURBS surface.	The offsets between successive control points in the para-
		   metric 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  defi-
       nition, 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) x (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)

															       GLUNURBSSURFACE(3G)