GLUNURBSCURVE
Section: Misc. Reference Manual Pages (3G)
Index
Return to Main Contents
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 )
delim $$
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 singleprecision floatingpoint 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
onedimensional 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 twodimensional (u
and v)
parameter space. If it is GLU_MAP1_TRIM_3, then it describes a
curve in twodimensional 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)
Index
 NAME

 C SPECIFICATION

 PARAMETERS

 DESCRIPTION

 EXAMPLE

 NOTES

 SEE ALSO

linux.jgfs.net manual pages