GLUBEGINCURVE() MachTen Programmer’s Manual GLUBEGINCURVE()

NAME
gluBeginCurve, gluEndCurve - delimit a NURBS curve defini-
tion

C SPECIFICATION
void gluBeginCurve( GLUnurbs* nurb )

void gluEndCurve( GLUnurbs* nurb )

delim $$

PARAMETERS
nurb Specifies the NURBS object (created with gluNewNurb-
sRenderer).

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 glu-
EndCurve.

GL 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 speci-
fied as NURBS curves:

gluBeginCurve(nobj);
gluNurbsCurve(nobj, ..., GL_MAP1_TEXTURE_COORD_2);
gluNurbsCurve(nobj, ..., GL_MAP1_NORMAL);
gluNurbsCurve(nobj, ..., GL_MAP1_VERTEX_4); gluEnd-
Curve(nobj);

SEE ALSO
gluBeginSurface, gluBeginTrim, gluNewNurbsRenderer,
gluNurbsCurve, glPopAttrib, glPushAttrib

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