Section: Misc. Reference Manual Pages (3G)
- define the shape of a NURBS curve
GLenum type )
Specifies the NURBS object (created with gluNewNurbsRenderer).
Specifies the number of knots in knots.
knotCount equals the number of control points plus the order.
Specifies an array of knotCount nondecreasing knot values.
Specifies the offset (as a number of single-precision floating-point values)
between successive curve control points.
Specifies a pointer to an array of control points. The coordinates must
agree with type, specified below.
Specifies the order of the NURBS curve. order equals degree + 1, hence
a cubic curve has an order of 4.
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.
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
parameter space. If it is GLU_MAP1_TRIM_3, then it describes a
curve in two-dimensional homogeneous (u, v, and w)
See the gluBeginTrim reference page for more discussion about trimming
The following commands render a textured NURBS curve with normals:
gluNurbsCurve(nobj, ..., GL_MAP1_TEXTURE_COORD_2);
gluNurbsCurve(nobj, ..., GL_MAP1_NORMAL);
gluNurbsCurve(nobj, ..., GL_MAP1_VERTEX_4);
To define trim curves which stitch well, use gluPwlCurve