gluNurbsCurve
The gluNurbsCurve function defines the shape of a NURBS curve.
void gluNurbsCurve(
GLUnurbsObj *nobj, GLint nknots, GLfloat *knot, GLint stride, GLfloat *ctlarray, GLint order, GLenum type);
Parameters
- nobj
The NURBS object (created with gluNewNurbsRenderer). - nknots
The number of knots in knot. The nknots parameter equals the number of control points plus the order. - knot
An array of nknots nondecreasing knot values. - stride
The offset (as a number of single precisionfloating-point values) between successive curve control points. - ctlarray
A pointer to an array of control points. The coordinates must agree with type. - order
The order of the NURBS curve. The order parameter equals degree + 1; hence a cubic curve has an order of 4. - type
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.
Remarks
When gluNurbsCurve appears between a gluBeginCurve/gluEndCurve pair, it describes a curve to be rendered. You associate positional, texture, and color coordinates by presenting each as a separate gluNurbsCurve between a gluBeginCurve/gluEndCurve pair. Do not make more than one call to gluNurbsCurve for color, position, and texture data within a single gluBeginCurve/gluEndCurve pair. Make exactly one call 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 describes a trimming curve on a NURBS surface. If type is GLU_MAP1_TRIM_2, it describes a curve in two-dimensional (u and v) parameter space. If it is GLU_MAP1_TRIM_3, it describes a curve in two-dimensional homogeneous (u, v, and w) parameter space. For more discussion about trimming curves, see gluBeginTrim.
Example
The following functions 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);
Requirements
** Windows NT/2000:** Requires Windows NT 3.5 or later.
** Windows 95/98:** Requires Windows 95 or later. Available as a redistributable for Windows 95.
** Header:** Declared in Glu.h.
** Library:** Use Glu32.lib.
See Also
gluBeginCurve, gluBeginTrim, gluEndCurve, gluEndTrim, gluNewNurbsRenderer, gluPwlCurve