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gluTessBeginPolygon - delimit a polygon description
void
gluTessBeginPolygon( GLUtesselator* tess,
GLvoid* data )
eqn not supported
- tess
- Specifies the tessellation object (created
with gluNewTess).
- data
- Specifies a pointer to user polygon data.
gluTessBeginPolygon
and gluTessEndPolygon delimit the definition of a convex, concave or self-intersecting
polygon. Within each gluTessBeginPolygon/gluTessEndPolygon pair, there must
be one or more calls to gluTessBeginContour/gluTessEndContour. Within each
contour, there are 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, gluTessBeginContour, and gluTessEndContour
reference pages for more details.
data is a pointer to a user-defined data
structure. If the appropriate callback(s) are specified (see gluTessCallback),
then this pointer is returned to the callback function(s). Thus, it is
a convenient way to store per-polygon information.
Once gluTessEndPolygon
is called, the polygon is tessellated, and the resulting triangles are
described through callbacks. See gluTessCallback for descriptions of the
callback functions.
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);
gluTessBeginContour(tobj);
gluTessVertex(tobj, v5, v5);
gluTessVertex(tobj, v6, v6);
gluTessVertex(tobj, v7, v7);
gluTessEndContour(tobj);
gluTessEndPolygon(tobj);
gluNewTess(3G)
, gluTessBeginContour(3G)
,
gluTessVertex(3G)
, gluTessCallback(3G)
, gluTessProperty(3G)
, gluTessNormal(3G)
,
gluTessEndPolygon(3G)
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