upstream-man-pages/man2/xhtml/gluBeginPolygon.xml

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   3 <?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>gluBeginPolygon</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="gluBeginPolygon"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>gluBeginPolygon — delimit a polygon description</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">gluBeginPolygon</b>(</code></td><td>GLUtesselator*  </td><td><var class="pdparam">tess</var><code>)</code>;</td></tr></table></div></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">gluEndPolygon</b>(</code></td><td>GLUtesselator*  </td><td><var class="pdparam">tess</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>tess</code></em></span></dt><dd><p>
   4                     Specifies the tessellation object (created with <a class="citerefentry" href="gluNewTess.xml"><span class="citerefentry"><span class="refentrytitle">gluNewTess</span></span></a>).
   5                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
   6             <code class="function">gluBeginPolygon</code> and <a class="citerefentry" href="gluEndPolygon.xml"><span class="citerefentry"><span class="refentrytitle">gluEndPolygon</span></span></a> delimit the definition of a
   7             nonconvex polygon.
   8             To define such a polygon, first call <code class="function">gluBeginPolygon</code>.
   9             Then define the contours of the polygon
  10             by calling
  11             <a class="citerefentry" href="gluTessVertex.xml"><span class="citerefentry"><span class="refentrytitle">gluTessVertex</span></span></a> for each vertex
  12             and <a class="citerefentry" href="gluNextContour.xml"><span class="citerefentry"><span class="refentrytitle">gluNextContour</span></span></a> to start each new contour.
  13             Finally, call <a class="citerefentry" href="gluEndPolygon.xml"><span class="citerefentry"><span class="refentrytitle">gluEndPolygon</span></span></a>
  14             to signal the end of the definition.
  15             See the <a class="citerefentry" href="gluTessVertex.xml"><span class="citerefentry"><span class="refentrytitle">gluTessVertex</span></span></a> and
  16             <a class="citerefentry" href="gluNextContour.xml"><span class="citerefentry"><span class="refentrytitle">gluNextContour</span></span></a> reference pages for more details.
  17         </p><p>
  18             Once <a class="citerefentry" href="gluEndPolygon.xml"><span class="citerefentry"><span class="refentrytitle">gluEndPolygon</span></span></a> is called, the polygon is tessellated, and the
  19             resulting triangles are described through callbacks.
  20             See <a class="citerefentry" href="gluTessCallback.xml"><span class="citerefentry"><span class="refentrytitle">gluTessCallback</span></span></a> for descriptions of the callback functions.
  21         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
  22             This command is obsolete and is provided for backward compatibility
  23             only. Calls to <code class="function">gluBeginPolygon</code> are mapped to
  24             <a class="citerefentry" href="gluTessBeginPolygon.xml"><span class="citerefentry"><span class="refentrytitle">gluTessBeginPolygon</span></span></a>
  25             followed by
  26             <a class="citerefentry" href="gluTessBeginContour.xml"><span class="citerefentry"><span class="refentrytitle">gluTessBeginContour</span></span></a>. Calls to <a class="citerefentry" href="gluEndPolygon.xml"><span class="citerefentry"><span class="refentrytitle">gluEndPolygon</span></span></a> are mapped
  27             to <a class="citerefentry" href="gluTessEndContour.xml"><span class="citerefentry"><span class="refentrytitle">gluTessEndContour</span></span></a> followed by <a class="citerefentry" href="gluTessEndPolygon.xml"><span class="citerefentry"><span class="refentrytitle">gluTessEndPolygon</span></span></a>.
  28         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="example"></a><h2>Example</h2><p>
  29             A quadrilateral with a triangular hole in it can be described like this:
  30             </p><pre class="programlisting">
  31 gluBeginPolygon(tobj);
  32    gluTessVertex(tobj, v1, v1);
  33    gluTessVertex(tobj, v2, v2);
  34    gluTessVertex(tobj, v3, v3);
  35    gluTessVertex(tobj, v4, v4);
  36 gluNextContour(tobj, GLU_INTERIOR);
  37    gluTessVertex(tobj, v5, v5);
  38    gluTessVertex(tobj, v6, v6);
  39    gluTessVertex(tobj, v7, v7);
  40 gluEndPolygon(tobj);
  41             </pre><p>
  42         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
  43             <a class="citerefentry" href="gluNewTess.xml"><span class="citerefentry"><span class="refentrytitle">gluNewTess</span></span></a>,
  44             <a class="citerefentry" href="gluNextContour.xml"><span class="citerefentry"><span class="refentrytitle">gluNextContour</span></span></a>,
  45             <a class="citerefentry" href="gluTessBeginContour.xml"><span class="citerefentry"><span class="refentrytitle">gluTessBeginContour</span></span></a>,
  46             <a class="citerefentry" href="gluTessBeginPolygon.xml"><span class="citerefentry"><span class="refentrytitle">gluTessBeginPolygon</span></span></a>,
  47             <a class="citerefentry" href="gluTessCallback.xml"><span class="citerefentry"><span class="refentrytitle">gluTessCallback</span></span></a>,
  48             <a class="citerefentry" href="gluTessVertex.xml"><span class="citerefentry"><span class="refentrytitle">gluTessVertex</span></span></a>
  49         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
  50             Copyright <span class="trademark"></span>© 1991-2006
  51             Silicon Graphics, Inc. This document is licensed under the SGI
  52             Free Software B License. For details, see
  53             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
  54         </p></div></div></body></html>