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gluNurbsCurve
Chapter 12
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gluNurbsCurve
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 non-decreasing 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 anyof the valid
one-dimensional evaluator types (such as GL_MAP1_VERTEX_3 or
GL_MAP1_COLOR_4). Between a gluBeginCurve/gluEndCurve 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. Exactlyone call must bemade to describe the position
of the curve (a type of GL_MAP1_VERTEX_3 or GL_MAP1_VERTEX_4).
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