Tao.OpenGl SDK Documentation

Glu.gluTessBeginPolygon Method (GLUtesselator, Int16[])

Delimits a polygon description.

[Visual Basic]
Overloads Public Shared Sub gluTessBeginPolygon( _
   ByVal tess As GLUtesselator, _
   ByVal data As Short() _
)
[C#]
public static void gluTessBeginPolygon(
   GLUtesselator tess,
   short[] data
);

Parameters

tess
The tessellation object (created with gluNewTess).
data
A pointer to a programmer defined?–polygon data structure.

Remarks

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.

EXAMPLE

The following describes a quadrilateral with a triangular hole:

            Glu.gluTessBeginPolygon(tobj, null);
            Glu.gluTessBeginContour(tobj);
            Glu.gluTessVertex(tobj, v1, v1);
            Glu.gluTessVertex(tobj, v2, v2);
            Glu.gluTessVertex(tobj, v3, v3);
            Glu.gluTessVertex(tobj, v4, v4);
            Glu.gluTessEndContour(tobj);
            Glu.gluTessBeginContour(tobj);
            Glu.gluTessVertex(tobj, v5, v5);
            Glu.gluTessVertex(tobj, v6, v6);
            Glu.gluTessVertex(tobj, v7, v7);
            Glu.gluTessEndContour(tobj);
            Glu.gluTessEndPolygon(tobj);
            

See Also

Glu Class | Tao.OpenGl Namespace | Glu.gluTessBeginPolygon Overload List | gluNewTess | gluTessBeginContour | gluTessCallback | gluTessEndPolygon | gluTessNormal | gluTessProperty | gluTessVertex