= We have moved =
This page has been moved to
[https://github.com/Xpra-org/xpra/wiki/Debugging]

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''Archived copy:''

{{{#!div class="box"
[[Image(https://xpra.org/icons/bugs.png)]]
= OpenGL Debugging =

See also: [/wiki/ClientRendering#OpenGLRelatedTickets] and [https://xpra.org/trac/wiki/ClientRendering/OpenGL OpenGL client rendering]

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The first step is to run the client with {{{-d opengl}}}, this should log a lot more information about opengl calls and is often enough to spot the source of the problem

Then there is also the environment variable {{{XPRA_OPENGL_DEBUG=1}}} which will enable the {{{GREMEDY}}} extension if present.

If these options are not sufficient to identify the source of the problem, you can use other tools to dig into the opengl rendering:
* Apitrace (see below)
* [https://github.com/ValveSoftware/vogl vogl]
* [https://developer.nvidia.com/linux-graphics-debugger NVidia's Linux Graphics Debugger]
}}}

{{{#!div class="box"
== Apitrace Installation ==

The *`Apitrace`* tool will get a dump of the `OpenGL` command stream, allowing it to be sent to the developers for replaying and investigation.

* On Linux:
Download [https://github.com/apitrace/apitrace Apitrace], build it according to the documentation: [https://github.com/apitrace/apitrace/blob/master/docs/INSTALL.markdown apitrace INSTALL]

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* On Windows:
You can use pre-built binaries found at [http://people.freedesktop.org/~jrfonseca/apitrace/]
Try to always use the latest version and fallback to an older one if it doesn't work.
}}}

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== Apitrace Usage ==

This trace will enable you to replay the actions of the client without having to re-run it; giving you additional error tracing, ability to send the trace to another person, and ability to replay the exact same steps every time.

Use as follows:
{{{
$ apitrace trace xpra attach <your regular commandline>
}}}
- Do whatever is needed to reproduce the issue you are experiencing. Beware: Apitrace is keeping a copy of everything you do in RAM, it's going to be huge, so don't run the session for too long, and focus on reproducing one issue at a time.
- Exit Xpra when done
{{{
$ qapitrace
}}}
`File` -> `load the trace`
Then go to `Trace` -> `Replay` and check both boxes

Apitrace will replay your trace and report in the bottom panel any errors it found, with additional explanation as compared to what the GL driver typically gives.

Be ready to send the {{{.trace}}} file to the developers for further investigation.
}}}