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<base href="https://bugs.freedesktop.org/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Regression related to mesa/readpix"
href="https://bugs.freedesktop.org/show_bug.cgi?id=94280">94280</a>
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<th>Summary</th>
<td>Regression related to mesa/readpix
</td>
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<th>Product</th>
<td>Mesa
</td>
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<th>Version</th>
<td>git
</td>
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<th>Hardware</th>
<td>Other
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>Mesa core
</td>
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<th>Assignee</th>
<td>mesa-dev@lists.freedesktop.org
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<th>Reporter</th>
<td>kennethmorrismartin@gmail.com
</td>
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<th>QA Contact</th>
<td>mesa-dev@lists.freedesktop.org
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<pre>It appears there was a regression related to recent changes in mesa/readpix. It
could be that the changes exposed something bad in our code, but it works
everywhere else so ...
Specifically it happened with
Last week this test started failing on hythloth's nightly Mesa builds
(along with a few other tests):
* OpenGL2: <a href="https://open.cdash.org/viewTest.php?onlyfailed&buildid=4229706">https://open.cdash.org/viewTest.php?onlyfailed&buildid=4229706</a>
<a href="https://open.cdash.org/testDetails.php?test=418931875&build=4229706">https://open.cdash.org/testDetails.php?test=418931875&build=4229706</a>
* OpenGL1: <a href="https://open.cdash.org/viewTest.php?onlyfailed&buildid=4230126">https://open.cdash.org/viewTest.php?onlyfailed&buildid=4230126</a>
<a href="https://open.cdash.org/testDetails.php?test=418952240&build=4230126">https://open.cdash.org/testDetails.php?test=418952240&build=4230126</a>
For now I've checked out a mesa that still works and stopped updating.
The problem bisects to:
mesa/readpix: Clip ReadPixels() area to the ReadBuffer's
<a href="https://cgit.freedesktop.org/mesa/mesa/commit/?id=605832736a6d9427ad894d403cceeb74a5b18dc1">https://cgit.freedesktop.org/mesa/mesa/commit/?id=605832736a6d9427ad894d403cceeb74a5b18dc1</a>
and still occurs after some related follow-up changes to Mesa:
mesa/readpix: Don't clip in _mesa_readpixels()
<a href="https://cgit.freedesktop.org/mesa/mesa/commit/?id=b89a8a15c240418d1859947b5114993ecdf424fb">https://cgit.freedesktop.org/mesa/mesa/commit/?id=b89a8a15c240418d1859947b5114993ecdf424fb</a>
mesa/readpix: Dedent former _mesa_readpixels() if block
<a href="https://cgit.freedesktop.org/mesa/mesa/commit/?id=c624241ef47c3a6ea2d1177969328bd4547e45a2">https://cgit.freedesktop.org/mesa/mesa/commit/?id=c624241ef47c3a6ea2d1177969328bd4547e45a2</a>
Valgrind reports that vtkImageDifference encounters uninitialized memory
after the change to Mesa but not before. That looks consistent with the
messy corner of the test image seen in the above links. Mesa is no longer
populating the full image with data.
I'll post an apitrace file run with an old mesa that hopefully will show the
problem for you should you not want to build VTK yourself.</pre>
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