glunurbssurface(3g) [xfree86 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)

Check Out this Related Man Page

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, gluBeginTrim, gluNewNurbsRenderer, gluPwlCurve

																 GLUNURBSCURVE(3G)

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glunurbssurface(3g) [xfree86 man page]

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