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<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN" "http://www.w3.org/TR/MathML2/dtd/xhtml-math11-f.dtd">
<html
xmlns="http://www.w3.org/1999/xhtml"
xmlns:mml="http://www.w3.org/1998/Math/MathML"
><head><title>gluNextContour</title><link rel="stylesheet" href="style.css" type="text/css"/><meta name="generator" content="DocBook XSL Stylesheets V1.59.1"/><link rel="home" href="index.xml" title="PyOpenGL 2.0.1.07 Man Pages"/><link rel="up" href="reference-GLU.xml" title="GLU"/><link rel="previous" href="gluNewTess.3G.xml" title="gluNewTess"/><link rel="next" href="gluNurbsCallback.3G.xml" title="gluNurbsCallback"/></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">gluNextContour</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="gluNewTess.3G.xml">Prev</a></td><th width="60%" align="center">GLU</th><td width="20%" align="right"><a accesskey="n" href="gluNurbsCallback.3G.xml">Next</a></td></tr></table><hr/></div><div class="refentry" lang="en"><a name="gluNextContour.3G"/><div class="titlepage"/><div class="refnamediv"><a name="gluNextContour.3G-name"/><h2>Name</h2><p>gluNextContour — mark the beginning of another contour</p></div><div class="refsynopsisdiv"><a name="gluNextContour.3G-c_spec"/><h2>C Specification</h2><table class="funcprototype" border="0" cellpadding="0" cellspacing="0"><tr><td valign="top"><code>void<tt>gluNextContour</tt></code></td><td valign="top"><code>(</code></td><td valign="top"><code>GLUtesselator*<i><tt>tess</tt></i>, GLenum<i><tt>type</tt></i>);</code></td></tr></table></div><div class="refsynopsisdiv"><a name="gluNextContour.3G-python_spec"/><h2>Python Specification</h2><table class="funcprototype" border="0" cellpadding="0" cellspacing="0"><tr><td valign="top"><code><tt>gluNextContour</tt></code></td><td valign="top"><code>(</code></td><td valign="top"><code><i><tt>tess</tt></i>, <i><tt>type</tt></i>) →<tt>None</tt></code></td></tr></table></div><div class="refsect1" lang="en"><a name="gluNextContour.3G-parameters"/><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><i><tt>tess</tt></i></span></dt><dd>
Specifies the tessellation object (created with <a href="gluNewTess.3G.xml"><tt>gluNewTess</tt></a>).
</dd><dt><span class="term"><i><tt>type</tt></i></span></dt><dd>
Specifies the type of the contour being defined. Valid values are <tt>GLU_EXTERIOR</tt>,
<tt>GLU_INTERIOR</tt>, <tt>GLU_UNKNOWN</tt>, <tt>GLU_CCW</tt>, and
<tt>GLU_CW</tt>.
</dd></dl></div></div><div class="refsect1" lang="en"><a name="gluNextContour.3G-description"/><h2>Description</h2><p>
<tt>gluNextContour</tt> is used in describing polygons with multiple contours. After the first contour has
been described through a series of <a href="gluTessVertex.3G.xml"><tt>gluTessVertex</tt></a> calls, a
<tt>gluNextContour</tt> call indicates that the previous contour is complete and that the next contour is
about to begin. Another series of <a href="gluTessVertex.3G.xml"><tt>gluTessVertex</tt></a> calls is then used to describe
the new contour. This process can be repeated until all contours have been described.
</p><p>
<i><tt>type</tt></i> defines what type of contour follows. The legal contour types are as follows:
</p><div class="variablelist"><dl><dt><span class="term"><tt>GLU_EXTERIOR</tt></span></dt><dd>
An exterior contour defines an exterior boundary of the polygon.
</dd><dt><span class="term"><tt>GLU_INTERIOR</tt></span></dt><dd>
An interior contour defines an interior boundary of the polygon (such as a hole).
</dd><dt><span class="term"><tt>GLU_UNKNOWN</tt></span></dt><dd>
An unknown contour is analyzed by the library to determine if it is interior or exterior.
</dd><dt><span class="term"><tt>GLU_CW</tt>, </span><span class="term"><tt>GLU_CCW</tt>,</span></dt><dd>
The first <tt>GLU_CCW</tt> or <tt>GLU_CW</tt> 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.
</dd></dl></div><p>
If one contour is of type <tt>GLU_CCW</tt> or <tt>GLU_CW</tt>, then all contours must be of the
same type (if they are not, then all <tt>GLU_CCW</tt> and <tt>GLU_CW</tt> contours will be
changed to <tt>GLU_UNKNOWN</tt>).
</p><p>
Note that there is no real difference between the <tt>GLU_CCW</tt> and <tt>GLU_CW</tt> contour
types.
</p><p>
Before the first contour is described, <tt>gluNextContour</tt> can be called to define the type of the
first contour. If <tt>gluNextContour</tt> is not called before the first contour, then the first contour is
marked <tt>GLU_EXTERIOR</tt>.
</p><p>
This command is obsolete and is provided for backward compatibility only. Calls to <tt>gluNextContour</tt>
are mapped to <a href="gluTessBeginContour.3G.xml"><tt>gluTessEndContour</tt></a> followed by <a href="gluTessBeginContour.3G.xml"><tt>gluTessBeginContour</tt></a>.
</p></div><div class="refsect1" lang="en"><a name="gluNextContour.3G-example"/><h2>Example</h2><p>
A quadrilateral with a triangular hole in it can be described as follows: 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);
</p></div><div class="refsect1" lang="en"><a name="gluNextContour.3G-see_also"/><h2>See Also</h2><p>
<span class="simplelist"><a href="gluBeginPolygon.3G.xml">gluBeginPolygon</a>, <a href="gluNewTess.3G.xml">gluNewTess</a>, <a href="gluTessCallback.3G.xml">gluTessCallback</a>, <a href="gluTessVertex.3G.xml">gluTessVertex</a>, <a href="gluTessBeginContour.3G.xml">gluTessBeginContour</a></span>
</p></div></div><div class="navfooter"><hr/><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="gluNewTess.3G.xml">Prev</a></td><td width="20%" align="center"><a accesskey="u" href="reference-GLU.xml">Up</a></td><td width="40%" align="right"><a accesskey="n" href="gluNurbsCallback.3G.xml">Next</a></td></tr><tr><td width="40%" align="left" valign="top">gluNewTess</td><td width="20%" align="center"><a accesskey="h" href="index.xml">Home</a></td><td width="40%" align="right" valign="top">gluNurbsCallback</td></tr></table></div></body></html>
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