--- /dev/null
+<?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="gluNextContour">
+ <refmeta>
+ <refmetainfo>
+ <copyright>
+ <year>1991-2006</year>
+ <holder>Silicon Graphics, Inc.</holder>
+ </copyright>
+ </refmetainfo>
+ <refentrytitle>gluNextContour</refentrytitle>
+ <manvolnum>3G</manvolnum>
+ </refmeta>
+ <refnamediv>
+ <refname>gluNextContour</refname>
+ <refpurpose>mark the beginning of another contour</refpurpose>
+ </refnamediv>
+ <refsynopsisdiv><title>C Specification</title>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>void <function>gluNextContour</function></funcdef>
+ <paramdef>GLUtesselator* <parameter>tess</parameter></paramdef>
+ <paramdef>GLenum <parameter>type</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>
+ <varlistentry>
+ <term><parameter>type</parameter></term>
+ <listitem>
+ <para>
+ Specifies the type of the contour being defined. Valid values are
+ <constant>GLU_EXTERIOR</constant>,
+ <constant>GLU_INTERIOR</constant>,
+ <constant>GLU_UNKNOWN</constant>,
+ <constant>GLU_CCW</constant>, and
+ <constant>GLU_CW</constant>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1 id="description"><title>Description</title>
+ <para>
+ <function>gluNextContour</function> is used in describing polygons with multiple contours. After the first
+ contour has been described through a series of <citerefentry><refentrytitle>gluTessVertex</refentrytitle></citerefentry> calls,
+ a <function>gluNextContour</function> call indicates that the previous contour is complete and that the
+ next contour is about to begin.
+ Another series of <citerefentry><refentrytitle>gluTessVertex</refentrytitle></citerefentry> calls is then used to describe the new
+ contour. This process can be repeated until all contours have been described.
+ </para>
+ <para>
+ <parameter>type</parameter> defines what type of contour follows.
+ The legal contour types are as follows:
+ </para>
+ <variablelist>
+ <varlistentry>
+ <term><constant>GLU_EXTERIOR</constant></term>
+ <listitem>
+ <para>
+ An exterior contour defines an exterior boundary of the polygon.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GLU_INTERIOR</constant></term>
+ <listitem>
+ <para>
+ An interior contour defines an interior boundary of the polygon (such as
+ a hole).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GLU_UNKNOWN</constant></term>
+ <listitem>
+ <para>
+ An unknown contour is analyzed by the library to determine if it is interior
+ or exterior.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GLU_CCW</constant>, </term>
+ <listitem>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GLU_CW</constant></term>
+ <listitem>
+ <para>
+ The first <constant>GLU_CCW</constant> or <constant>GLU_CW</constant> contour defined is considered to
+ be exterior. All other contours are considered to be exterior if they
+ are oriented in the same direction (clockwise or counterclockwise) as
+ the first contour, and interior if they are not.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <para>
+ If one contour is of type <constant>GLU_CCW</constant> or <constant>GLU_CW</constant>, then all
+ contours must be of the same type (if they are not, then all <constant>GLU_CCW</constant>
+ and <constant>GLU_CW</constant> contours will be changed to <constant>GLU_UNKNOWN</constant>).
+ </para>
+ <para>
+ Note that there is no real difference between the <constant>GLU_CCW</constant> and
+ <constant>GLU_CW</constant> contour types.
+ </para>
+ <para>
+ Before the first contour is described, <function>gluNextContour</function> can be called to
+ define the type of the first contour.
+ If <function>gluNextContour</function> is not called before the first contour, then the first contour is
+ marked <constant>GLU_EXTERIOR</constant>.
+ </para>
+ <para>
+ This command is obsolete and is provided for backward compatibility
+ only. Calls to <function>gluNextContour</function> are mapped to <citerefentry><refentrytitle>gluTessEndContour</refentrytitle></citerefentry>
+ followed by
+ <citerefentry><refentrytitle>gluTessBeginContour</refentrytitle></citerefentry>.
+ </para>
+ </refsect1>
+ <refsect1 id="example"><title>Example</title>
+ <para>
+ A quadrilateral with a triangular hole in it can be described as follows:
+ <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>gluBeginPolygon</refentrytitle></citerefentry>,
+ <citerefentry><refentrytitle>gluNewTess</refentrytitle></citerefentry>,
+ <citerefentry><refentrytitle>gluTessBeginContour</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>
HCoop / clinton / guile-figl.git / blobdiff