fgluBeginSurface(3G) OpenGL Reference fgluBeginSurface(3G)NAME
fgluBeginSurface, fgluEndSurface - delimit a NURBS surface definition
FORTRAN SPECIFICATION
SUBROUTINE fgluBeginSurface( CHARACTER*8 nurb )
SUBROUTINE fgluEndSurface( CHARACTER*8 nurb )
PARAMETERS
nurb Specifies the NURBS object (created with fgluNewNurbsRenderer).
DESCRIPTION
Use fgluBeginSurface to mark the beginning of a NURBS surface definition.
After calling fgluBeginSurface, make one or more calls to
fgluNurbsSurface to define the attributes of the surface. Exactly one of
these calls to fgluNurbsSurface must have a surface type of
GL_MAP2_VERTEX_3 or GL_MAP2_VERTEX_4. To mark the end of the NURBS
surface definition, call fgluEndSurface.
Trimming of NURBS surfaces is supported with fgluBeginTrim, fgluPwlCurve,
fgluNurbsCurve, and fgluEndTrim. See the fgluBeginTrim reference page for
details.
GL evaluators are used to render the NURBS surface as a set of polygons.
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 surface with normals; the
texture coordinates and normals are also described as NURBS surfaces:
gluBeginSurface(nobj);
gluNurbsSurface(nobj, ..., GL_MAP2_TEXTURE_COORD_2);
gluNurbsSurface(nobj, ..., GL_MAP2_NORMAL);
gluNurbsSurface(nobj, ..., GL_MAP2_VERTEX_4);
gluEndSurface(nobj);
SEE ALSO
fgluBeginCurve, fgluBeginTrim, fgluNewNurbsRenderer, fgluNurbsCurve,
fgluNurbsSurface, fgluPwlCurve
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