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  <title>Application Issues</title>
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<div class="header">
  <h1>The Mesa 3D Graphics Library</h1>
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<h1>Application Issues</h1>

<p>
This page documents known issues with some OpenGL applications.
</p>


<h2>Topogun</h2>

<p>
<a href="http://www.topogun.com/">Topogun</a> for Linux (version 2, at least)
creates a GLX visual without requesting a depth buffer.
This causes bad rendering if the OpenGL driver happens to choose a visual
without a depth buffer.
</p>

<p>
Mesa 9.1.2 and later (will) support a DRI configuration option to work around
this issue.
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Using the <a href="https://dri.freedesktop.org/wiki/DriConf">driconf</a> tool,
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set the "Create all visuals with a depth buffer" option before running Topogun.
Then, all GLX visuals will be created with a depth buffer.
</p>


<h2>Old OpenGL games</h2>

<p>
Some old OpenGL games (approx. ten years or older) may crash during
start-up because of an extension string buffer-overflow problem.
</p>

<p>
The problem is a modern OpenGL driver will return a very long string
for the glGetString(GL_EXTENSIONS) query and if the application
naively copies the string into a fixed-size buffer it can overflow the
buffer and crash the application.
</p>

<p>
The work-around is to set the MESA_EXTENSION_MAX_YEAR environment variable
to the approximate release year of the game.
This will cause the glGetString(GL_EXTENSIONS) query to only report extensions
older than the given year.
</p>

<p>
For example, if the game was released in 2001, do
<pre>
export MESA_EXTENSION_MAX_YEAR=2001
</pre>
before running the game.
</p>



<h2>Viewperf</h2>

<p>
See the <a href="viewperf.html">Viewperf issues</a> page for a detailed list
of Viewperf issues.
</p>


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