1991-2006 Silicon Graphics, Inc.
gluBeginPolygon 3G
gluBeginPolygon delimit a polygon description

## C Specification

void `gluBeginPolygon` GLUtesselator* tess

## C Specification

void `gluEndPolygon` GLUtesselator* tess

## Parameters

tess

  Specifies the tessellation object (created with gluNewTess).

## Description

`gluBeginPolygon` and gluEndPolygon delimit the definition of a nonconvex polygon. To define such a polygon, first call `gluBeginPolygon`. Then define the contours of the polygon by calling gluTessVertex for each vertex and gluNextContour to start each new contour. Finally, call gluEndPolygon to signal the end of the definition. See the gluTessVertex and gluNextContour reference pages for more details.

Once gluEndPolygon is called, the polygon is tessellated, and the resulting triangles are described through callbacks. See gluTessCallback for descriptions of the callback functions.

## Notes

This command is obsolete and is provided for backward compatibility only. Calls to `gluBeginPolygon` are mapped to gluTessBeginPolygon followed by gluTessBeginContour. Calls to gluEndPolygon are mapped to gluTessEndContour followed by gluTessEndPolygon.

## Example

A quadrilateral with a triangular hole in it can be described like this:

    gluBeginPolygon(tobj);
       gluTessVertex(tobj, v1, v1);
       gluTessVertex(tobj, v2, v2);
       gluTessVertex(tobj, v3, v3);
       gluTessVertex(tobj, v4, v4);
    gluNextContour(tobj, GLU_INTERIOR);
       gluTessVertex(tobj, v5, v5);
       gluTessVertex(tobj, v6, v6);
       gluTessVertex(tobj, v7, v7);
    gluEndPolygon(tobj);

## See Also

gluNewTess, gluNextContour, gluTessBeginContour, gluTessBeginPolygon, gluTessCallback, gluTessVertex

## Copyright

Copyright 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.