gluBeginCurve, gluEndCurve

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 surface as a set 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

glPopAttrib, glPushAttrib, gluBeginSurface, gluBeginTrim, gluNewNurbsRenderer, gluNurbsCurve

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© 1995 Uwe Behrens All rights reserved