<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN" "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd"> <refentry id="gluBeginPolygon"> <refmeta> <refmetainfo> <copyright> <year>1991-2006</year> <holder>Silicon Graphics, Inc.</holder> </copyright> </refmetainfo> <refentrytitle>gluBeginPolygon</refentrytitle> <manvolnum>3G</manvolnum> </refmeta> <refnamediv> <refname>gluBeginPolygon</refname> <refpurpose>delimit a polygon description</refpurpose> </refnamediv> <refsynopsisdiv><title>C Specification</title> <funcsynopsis> <funcprototype> <funcdef>void <function>gluBeginPolygon</function></funcdef> <paramdef>GLUtesselator* <parameter>tess</parameter></paramdef> </funcprototype> </funcsynopsis> </refsynopsisdiv> <refsynopsisdiv><title>C Specification</title> <funcsynopsis> <funcprototype> <funcdef>void <function>gluEndPolygon</function></funcdef> <paramdef>GLUtesselator* <parameter>tess</parameter></paramdef> </funcprototype> </funcsynopsis> </refsynopsisdiv> <!-- eqn: ignoring delim $$ --> <refsect1 id="parameters"><title>Parameters</title> <variablelist> <varlistentry> <term><parameter>tess</parameter></term> <listitem> <para> Specifies the tessellation object (created with <citerefentry><refentrytitle>gluNewTess</refentrytitle></citerefentry>). </para> </listitem> </varlistentry> </variablelist> </refsect1> <refsect1 id="description"><title>Description</title> <para> <function>gluBeginPolygon</function> and <citerefentry><refentrytitle>gluEndPolygon</refentrytitle></citerefentry> delimit the definition of a nonconvex polygon. To define such a polygon, first call <function>gluBeginPolygon</function>. Then define the contours of the polygon by calling <citerefentry><refentrytitle>gluTessVertex</refentrytitle></citerefentry> for each vertex and <citerefentry><refentrytitle>gluNextContour</refentrytitle></citerefentry> to start each new contour. Finally, call <citerefentry><refentrytitle>gluEndPolygon</refentrytitle></citerefentry> to signal the end of the definition. See the <citerefentry><refentrytitle>gluTessVertex</refentrytitle></citerefentry> and <citerefentry><refentrytitle>gluNextContour</refentrytitle></citerefentry> reference pages for more details. </para> <para> Once <citerefentry><refentrytitle>gluEndPolygon</refentrytitle></citerefentry> is called, the polygon is tessellated, and the resulting triangles are described through callbacks. See <citerefentry><refentrytitle>gluTessCallback</refentrytitle></citerefentry> for descriptions of the callback functions. </para> </refsect1> <refsect1 id="notes"><title>Notes</title> <para> This command is obsolete and is provided for backward compatibility only. Calls to <function>gluBeginPolygon</function> are mapped to <citerefentry><refentrytitle>gluTessBeginPolygon</refentrytitle></citerefentry> followed by <citerefentry><refentrytitle>gluTessBeginContour</refentrytitle></citerefentry>. Calls to <citerefentry><refentrytitle>gluEndPolygon</refentrytitle></citerefentry> are mapped to <citerefentry><refentrytitle>gluTessEndContour</refentrytitle></citerefentry> followed by <citerefentry><refentrytitle>gluTessEndPolygon</refentrytitle></citerefentry>. </para> </refsect1> <refsect1 id="example"><title>Example</title> <para> A quadrilateral with a triangular hole in it can be described like this: <programlisting> 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); </programlisting> </para> </refsect1> <refsect1 id="seealso"><title>See Also</title> <para> <citerefentry><refentrytitle>gluNewTess</refentrytitle></citerefentry>, <citerefentry><refentrytitle>gluNextContour</refentrytitle></citerefentry>, <citerefentry><refentrytitle>gluTessBeginContour</refentrytitle></citerefentry>, <citerefentry><refentrytitle>gluTessBeginPolygon</refentrytitle></citerefentry>, <citerefentry><refentrytitle>gluTessCallback</refentrytitle></citerefentry>, <citerefentry><refentrytitle>gluTessVertex</refentrytitle></citerefentry> </para> </refsect1> <refsect1 id="Copyright"><title>Copyright</title> <para> Copyright <trademark class="copyright"></trademark> 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>. </para> </refsect1> </refentry>