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<!-- begin header.html -->
<!--
The OpenGL Extension Wrangler Library
Copyright (C) 2002-2008, Milan Ikits <milan ikits[]ieee org>
Copyright (C) 2002-2008, Marcelo E. Magallon <mmagallo[]debian org>
Copyright (C) 2002, Lev Povalahev
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
* The name of the author may be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
THE POSSIBILITY OF SUCH DAMAGE.
-->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html/4/loose.dtd">
<!-- &nbsp;<img src="new.png" height="12" alt="NEW!"> -->
<html>
<head>
<title>GLEW: The OpenGL Extension Wrangler Library</title>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<link href="glew.css" type="text/css" rel="stylesheet">
</head>
<body bgcolor="#fff0d0">
<table border="0" width="100%" cellpadding="12" cellspacing="8" style="height:100%">
<tr>
<td bgcolor="#ffffff" align="left" valign="top" width="200">
<table border="0" width="100%" cellpadding="0" cellspacing="0" align="left">
<tr>
<td valign="top">
<table border="0" width="100%" cellpadding="0" cellspacing="0" align="left">
<tr><td align="center"><i>Latest Release: <a href="https://sourceforge.net/projects/glew/files/glew/1.6.0/">1.6.0</a></i></td></tr>
<tr><td align="center"><br></td></tr>
<tr><td align="center"><img src="./glew.png" alt="GLEW Logo" width="97" height="75"></td></tr>
<tr><td align="center"><br></td></tr>
<tr><td align="center">
<table border="0" cellpadding="0" cellspacing="0" align="center">
<tr><td align="center"><a href="index.html">Download</a></td></tr>
<tr><td align="center"><a href="install.html">Installation</a></td></tr>
<tr><td align="center">Basic Usage</td></tr>
<tr><td align="center"><a href="advanced.html">Advanced Usage</a></td></tr>
<tr><td align="center"><a href="credits.html">Credits & Copyright</a></td></tr>
<tr><td align="center"><a href="log.html">Change Log</a></td></tr>
<tr><td align="center"><a href="http://sourceforge.net/projects/glew/">Project Page</a></td></tr>
<tr><td align="center"><a href="https://sourceforge.net/mail/?group_id=67586">Mailing Lists</a></td></tr>
<tr><td align="center"><a href="http://sourceforge.net/tracker/?group_id=67586">Bug Tracker</a></td></tr>
</table>
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</table>
</td>
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<tr>
<td valign="bottom">
<table border="0" width="100%" cellpadding="5" cellspacing="0" align="left">
<tr><td align="center"><i>Last Update: 04-27-11</i></td></tr>
<tr><td align="center">
<a href="http://www.opengl.org"> <img src="./ogl_sm.jpg" width="68"
height="35" border="0" alt="OpenGL Logo"></a>
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width="88" height="31" border="0" alt="SourceForge Logo"></a>
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<!--- <tr><td align="center"><a
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width="88" height="32" border="0" alt="Support This Project"></a></td></tr> -->
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<td bgcolor="#ffffff" align="left" valign="top">
<h1>The OpenGL Extension Wrangler Library</h1>
<!-- end header.html -->
<h2>Initializing GLEW</h2>
<p>
First you need to create a valid OpenGL rendering context and call
<tt>glewInit()</tt> to initialize the extension entry points. If
<tt>glewInit()</tt> returns <tt>GLEW_OK</tt>, the initialization
succeeded and you can use the available extensions as well as core
OpenGL functionality. For example:
</p>
<p class="pre">
#include &lt;GL/glew.h&gt;<br>
#include &lt;GL/glut.h&gt;<br>
...<br>
glutInit(&amp;argc, argv);<br>
glutCreateWindow("GLEW Test");<br>
GLenum err = glewInit();<br>
if (GLEW_OK != err)<br>
{<br>
&nbsp;&nbsp;/* Problem: glewInit failed, something is seriously wrong. */<br>
&nbsp;&nbsp;fprintf(stderr, "Error: %s\n", glewGetErrorString(err));<br>
&nbsp;&nbsp;...<br>
}<br>
fprintf(stdout, "Status: Using GLEW %s\n", glewGetString(GLEW_VERSION));<br>
</p>
<h2>Checking for Extensions</h2>
<p>
Starting from GLEW 1.1.0, you can find out if a particular extension
is available on your platform by querying globally defined variables
of the form <tt>GLEW_{extension_name}</tt>:
</p>
<p class="pre">
if (GLEW_ARB_vertex_program)<br>
{<br>
&nbsp;&nbsp;/* It is safe to use the ARB_vertex_program extension here. */<br>
&nbsp;&nbsp;glGenProgramsARB(...);<br>
}<br>
</p>
<p>
<b>In GLEW 1.0.x, a global structure was used for this task. To ensure
binary compatibility between releases, the struct was replaced with a
set of variables.</b>
</p>
<p>
You can also check for core OpenGL functionality. For example, to
see if OpenGL 1.3 is supported, do the following:
</p>
<p class="pre">
if (GLEW_VERSION_1_3)<br>
{<br>
&nbsp;&nbsp;/* Yay! OpenGL 1.3 is supported! */<br>
}<br>
</p>
<p>
In general, you can check if <tt>GLEW_{extension_name}</tt> or
<tt>GLEW_VERSION_{version}</tt> is true or false.
</p>
<p>
It is also possible to perform extension checks from string
input. Starting from the 1.3.0 release, use <tt>glewIsSupported</tt>
to check if the required core or extension functionality is
available:
</p>
<p class="pre">
if (glewIsSupported("GL_VERSION_1_4&nbsp;&nbsp;GL_ARB_point_sprite"))<br>
{<br>
&nbsp;&nbsp;/* Great, we have OpenGL 1.4 + point sprites. */<br>
}<br>
</p>
<p>
For extensions only, <tt>glewGetExtension</tt> provides a slower alternative
(GLEW 1.0.x-1.2.x). <b>Note that in the 1.3.0 release </b>
<tt>glewGetExtension</tt> <b>was replaced with </b>
<tt>glewIsSupported</tt>.
</p>
<p class="pre">
if (glewGetExtension("GL_ARB_fragment_program"))<br>
{<br>
&nbsp;&nbsp;/* Looks like ARB_fragment_program is supported. */<br>
}<br>
</p>
<h2>Experimental Drivers</h2>
<p>
GLEW obtains information on the supported extensions from the graphics
driver. Experimental or pre-release drivers, however, might not
report every available extension through the standard mechanism, in
which case GLEW will report it unsupported. To circumvent this
situation, the <tt>glewExperimental</tt> global switch can be turned
on by setting it to <tt>GL_TRUE</tt> before calling
<tt>glewInit()</tt>, which ensures that all extensions with valid
entry points will be exposed.
</p>
<h2>Platform Specific Extensions</h2>
<p>
Platform specific extensions are separated into two header files:
<tt>wglew.h</tt> and <tt>glxew.h</tt>, which define the available
<tt>WGL</tt> and <tt>GLX</tt> extensions. To determine if a certain
extension is supported, query <tt>WGLEW_{extension name}</tt> or
<tt>GLXEW_{extension_name}</tt>. For example:
</p>
<p class="pre">
#include &lt;GL/wglew.h&gt;<br>
<br>
if (WGLEW_ARB_pbuffer)<br>
{<br>
&nbsp;&nbsp;/* OK, we can use pbuffers. */<br>
}<br>
else<br>
{<br>
&nbsp;&nbsp;/* Sorry, pbuffers will not work on this platform. */<br>
}<br>
</p>
<p>
Alternatively, use <tt>wglewIsSupported</tt> or
<tt>glxewIsSupported</tt> to check for extensions from a string:
</p>
<p class="pre">
if (wglewIsSupported("WGL_ARB_pbuffer"))<br>
{<br>
&nbsp;&nbsp;/* OK, we can use pbuffers. */<br>
}<br>
</p>
<h2>Utilities</h2>
<p>
GLEW provides two command-line utilities: one for creating a list of
available extensions and visuals; and another for verifying extension
entry points.
</p>
<h3>visualinfo: extensions and visuals</h3>
<p>
<tt>visualinfo</tt> is an extended version of <tt>glxinfo</tt>. The
Windows version creates a file called <tt>visualinfo.txt</tt>, which
contains a list of available OpenGL, WGL, and GLU extensions as well
as a table of visuals aka. pixel formats. Pbuffer and MRT capable
visuals are also included. For additional usage information, type
<tt>visualinfo -h</tt>.
</p>
<h3>glewinfo: extension verification utility</h3>
<p>
<tt>glewinfo</tt> allows you to verify the entry points for the
extensions supported on your platform. The Windows version
reports the results to a text file called <tt>glewinfo.txt</tt>. The
Unix version prints the results to <tt>stdout</tt>.
</p>
<p>Windows usage:</p>
<blockquote><pre>glewinfo [-pf &lt;id&gt;]</pre></blockquote>
<p>where <tt>&lt;id&gt;</tt> is the pixel format id for which the
capabilities are displayed.</p>
<p>Unix usage:</p>
<blockquote><pre>glewinfo [-display &lt;dpy&gt;] [-visual &lt;id&gt;]</pre></blockquote>
<p>where <tt>&lt;dpy&gt;</tt> is the X11 display and <tt>&lt;id&gt;</tt> is
the visual id for which the capabilities are displayed.</p>
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