fgluTessBeginPolygon(3G) OpenGL Reference fgluTessBeginPolygon(3G)NAMEfgluTessBeginPolygon - delimit a polygon description
FORTRAN SPECIFICATION
SUBROUTINE fgluTessBeginPolygon( CHARACTER*8 tess,
CHARACTER*8 data )
PARAMETERS
tess Specifies the tessellation object (created with fgluNewTess).
data Specifies a pointer to user polygon data.
DESCRIPTIONfgluTessBeginPolygon and fgluTessEndPolygon delimit the definition of a
convex, concave or self-intersecting polygon. Within each
fgluTessBeginPolygon/fgluTessEndPolygon pair, there must be one or more
calls to fgluTessBeginContour/fgluTessEndContour. Within each contour,
there are zero or more calls to fgluTessVertex. The vertices specify a
closed contour (the last vertex of each contour is automatically linked
to the first). See the fgluTessVertex, fgluTessBeginContour, and
fgluTessEndContour reference pages for more details.
data is a pointer to a user-defined data structure. If the appropriate
callback(s) are specified (see fgluTessCallback), then this pointer is
returned to the callback function(s). Thus, it is a convenient way to
store per-polygon information.
Once fgluTessEndPolygon is called, the polygon is tessellated, and the
resulting triangles are described through callbacks. See
fgluTessCallback for descriptions of the callback functions.
EXAMPLE
A quadrilateral with a triangular hole in it can be described as follows:
gluTessBeginPolygon(tobj, NULL);
gluTessBeginContour(tobj);
gluTessVertex(tobj, v1, v1);
gluTessVertex(tobj, v2, v2);
gluTessVertex(tobj, v3, v3);
gluTessVertex(tobj, v4, v4);
gluTessEndContour(tobj);
Page 1
fgluTessBeginPolygon(3G) OpenGL Reference fgluTessBeginPolygon(3G)gluTessBeginContour(tobj);
gluTessVertex(tobj, v5, v5);
gluTessVertex(tobj, v6, v6);
gluTessVertex(tobj, v7, v7);
gluTessEndContour(tobj);
gluTessEndPolygon(tobj);
SEE ALSO
fgluNewTess, fgluTessBeginContour, fgluTessVertex, fgluTessCallback,
fgluTessProperty, fgluTessNormal, fgluTessEndPolygon
Page 2