NAME

gluBeginCurve, gluEndCurve - delimit a NURBS curve definition

C SPECIFICATION

void gluBeginCurve( GLUnurbsObj *nobj )

void gluEndCurve( GLUnurbsObj *nobj )

PARAMETERS

nobj ? Specifies the NURBS object (created with gluNewNurbsRenderer).

DESCRIPTION

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(). See the "glPushAttrib" reference page for details on exactly what state these calls preserve.

EXAMPLE

The following commands 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);

SEE ALSO

"gluBeginSurface" , "gluBeginTrim" , "gluNewNurbsRenderer" , "gluNurbsCurve" , glPopAttrib, "glPushAttrib"