Javadoc
gluTessBeginContour and
#gluTessEndContour delimit
the definition of a polygon contour. Within each
gluTessBeginContour/
#gluTessEndContour pair,
there can be zero or more calls to
#gluTessVertex. The vertices
specify a closed contour (the last vertex of each contour is automatically
linked to the first). See the
#gluTessVertex reference page for more details. gluTessBeginContour
can only be called between
#gluTessBeginPolygon and
#gluTessEndPolygon.
Optional, throws GLException if not available in profile