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5  <title>Application Issues</title>
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9
10<div class="header">
11  <h1>The Mesa 3D Graphics Library</h1>
12</div>
13
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15<div class="content">
16
17<h1>Application Issues</h1>
18
19<p>
20This page documents known issues with some OpenGL applications.
21</p>
22
23
24<h2>Topogun</h2>
25
26<p>
27<a href="http://www.topogun.com/">Topogun</a> for Linux (version 2, at least)
28creates a GLX visual without requesting a depth buffer.
29This causes bad rendering if the OpenGL driver happens to choose a visual
30without a depth buffer.
31</p>
32
33<p>
34Mesa 9.1.2 and later (will) support a DRI configuration option to work around
35this issue.
36Using the <a href="http://dri.freedesktop.org/wiki/DriConf">driconf</a> tool,
37set the "Create all visuals with a depth buffer" option before running Topogun.
38Then, all GLX visuals will be created with a depth buffer.
39</p>
40
41
42<h2>Old OpenGL games</h2>
43
44<p>
45Some old OpenGL games (approx. ten years or older) may crash during
46start-up because of an extension string buffer-overflow problem.
47</p>
48
49<p>
50The problem is a modern OpenGL driver will return a very long string
51for the glGetString(GL_EXTENSIONS) query and if the application
52naively copies the string into a fixed-size buffer it can overflow the
53buffer and crash the application.
54</p>
55
56<p>
57The work-around is to set the MESA_EXTENSION_MAX_YEAR environment variable
58to the approximate release year of the game.
59This will cause the glGetString(GL_EXTENSIONS) query to only report extensions
60older than the given year.
61</p>
62
63<p>
64For example, if the game was released in 2001, do
65<pre>
66export MESA_EXTENSION_MAX_YEAR=2001
67</pre>
68before running the game.
69</p>
70
71
72
73<h2>Viewperf</h2>
74
75<p>
76See the <a href="viewperf.html">Viewperf issues</a> page for a detailed list
77of Viewperf issues.
78</p>
79
80
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