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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> |