gluBeginCurve, gluEndCurve

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The gluBeginCurve and gluEndCurve functions delimit a Non-Uniform Rational B-Spline (NURBS) curve definition.

void gluBeginCurve(
  GLUnurbsObj *nobj);void gluEndCurve(  GLUnurbsObj *nobj);

Parameters

Remarks

Use gluBeginCurve to mark the beginning of a NURBS curve definition. After calling gluBeginCurve, make one or more calls to gluNurbsCurve to define the attributes of the curve. Exactly one of the calls to gluNurbsCurve must have a curve type of GL_MAP1_VERTEX_3 or GL_MAP1_VERTEX_4. To mark the end of the NURBS curve definition, call gluEndCurve.

OpenGL evaluators are used to render the NURBS curve as a series of line segments. Evaluator state is preserved during rendering with glPushAttrib(GL_EVAL_BIT) and glPopAttrib. For information on exactly what state these calls preserve, see glPushAttrib.

Example

The following functions render a textured NURBS curve with normals; texture coordinates and normals are also specified as NURBS curves:

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

glPopAttrib, glPushAttrib, gluBeginSurface, gluBeginTrim, gluNewNurbsRenderer, gluNurbsCurve