113 lines
5.4 KiB
XML
113 lines
5.4 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
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"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
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<refentry id="gluBeginPolygon">
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<refmeta>
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<refmetainfo>
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<copyright>
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<year>1991-2006</year>
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<holder>Silicon Graphics, Inc.</holder>
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</copyright>
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</refmetainfo>
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<refentrytitle>gluBeginPolygon</refentrytitle>
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<manvolnum>3G</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>gluBeginPolygon</refname>
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<refpurpose>delimit a polygon description</refpurpose>
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</refnamediv>
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<refsynopsisdiv><title>C Specification</title>
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<funcsynopsis>
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<funcprototype>
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<funcdef>void <function>gluBeginPolygon</function></funcdef>
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<paramdef>GLUtesselator* <parameter>tess</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsynopsisdiv><title>C Specification</title>
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<funcsynopsis>
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<funcprototype>
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<funcdef>void <function>gluEndPolygon</function></funcdef>
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<paramdef>GLUtesselator* <parameter>tess</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<!-- eqn: ignoring delim $$ -->
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<refsect1 id="parameters"><title>Parameters</title>
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<variablelist>
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<varlistentry>
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<term><parameter>tess</parameter></term>
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<listitem>
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<para>
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Specifies the tessellation object (created with <citerefentry><refentrytitle>gluNewTess</refentrytitle></citerefentry>).
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1 id="description"><title>Description</title>
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<para>
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<function>gluBeginPolygon</function> and <citerefentry><refentrytitle>gluEndPolygon</refentrytitle></citerefentry> delimit the definition of a
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nonconvex polygon.
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To define such a polygon, first call <function>gluBeginPolygon</function>.
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Then define the contours of the polygon
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by calling
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<citerefentry><refentrytitle>gluTessVertex</refentrytitle></citerefentry> for each vertex
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and <citerefentry><refentrytitle>gluNextContour</refentrytitle></citerefentry> to start each new contour.
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Finally, call <citerefentry><refentrytitle>gluEndPolygon</refentrytitle></citerefentry>
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to signal the end of the definition.
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See the <citerefentry><refentrytitle>gluTessVertex</refentrytitle></citerefentry> and
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<citerefentry><refentrytitle>gluNextContour</refentrytitle></citerefentry> reference pages for more details.
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</para>
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<para>
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Once <citerefentry><refentrytitle>gluEndPolygon</refentrytitle></citerefentry> is called, the polygon is tessellated, and the
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resulting triangles are described through callbacks.
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See <citerefentry><refentrytitle>gluTessCallback</refentrytitle></citerefentry> for descriptions of the callback functions.
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</para>
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</refsect1>
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<refsect1 id="notes"><title>Notes</title>
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<para>
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This command is obsolete and is provided for backward compatibility
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only. Calls to <function>gluBeginPolygon</function> are mapped to
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<citerefentry><refentrytitle>gluTessBeginPolygon</refentrytitle></citerefentry>
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followed by
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<citerefentry><refentrytitle>gluTessBeginContour</refentrytitle></citerefentry>. Calls to <citerefentry><refentrytitle>gluEndPolygon</refentrytitle></citerefentry> are mapped
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to <citerefentry><refentrytitle>gluTessEndContour</refentrytitle></citerefentry> followed by <citerefentry><refentrytitle>gluTessEndPolygon</refentrytitle></citerefentry>.
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</para>
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</refsect1>
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<refsect1 id="example"><title>Example</title>
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<para>
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A quadrilateral with a triangular hole in it can be described like this:
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<programlisting>
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gluBeginPolygon(tobj);
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gluTessVertex(tobj, v1, v1);
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gluTessVertex(tobj, v2, v2);
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gluTessVertex(tobj, v3, v3);
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gluTessVertex(tobj, v4, v4);
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gluNextContour(tobj, GLU_INTERIOR);
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gluTessVertex(tobj, v5, v5);
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gluTessVertex(tobj, v6, v6);
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gluTessVertex(tobj, v7, v7);
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gluEndPolygon(tobj);
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</programlisting>
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</para>
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</refsect1>
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<refsect1 id="seealso"><title>See Also</title>
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<para>
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<citerefentry><refentrytitle>gluNewTess</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>gluNextContour</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>gluTessBeginContour</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>gluTessBeginPolygon</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>gluTessCallback</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>gluTessVertex</refentrytitle></citerefentry>
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</para>
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</refsect1>
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<refsect1 id="Copyright"><title>Copyright</title>
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<para>
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Copyright <trademark class="copyright"></trademark> 1991-2006
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Silicon Graphics, Inc. This document is licensed under the SGI
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Free Software B License. For details, see
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<ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
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</para>
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</refsect1>
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</refentry>
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