About **apitrace** ================== **apitrace** consists of a set of tools to: * trace OpenGL, OpenGL ES, D3D9, D3D8, D3D7, and DDRAW APIs calls to a file; * retrace OpenGL and OpenGL ES calls from a file; * inspect OpenGL state at any call while retracing; * visualize and edit trace files. Basic usage =========== Linux and Mac OS X ------------------ Run the application you want to trace as apitrace trace /path/to/application [args...] and it will generate a trace named `application.trace` in the current directory. You can specify the written trace filename by setting the `TRACE_FILE` environment variable before running. View the trace with apitrace dump --color application.trace | less -R Replay an OpenGL trace with glretrace application.trace Pass the `-sb` option to use a single buffered visual. Pass `--help` to glretrace for more options. Start the GUI as qapitrace application.trace Windows ------- * Copy `opengl32.dll`, `d3d8.dll`, or `d3d9.dll` from build/wrappers directory to the directory with the application you want to trace. * Run the application. * View the trace with \path\to\apitrace dump application.trace * Replay the trace with \path\to\glretrace application.trace Advanced command line usage =========================== Tracing manually ---------------- ### Linux ### Run the application you want to trace as LD_PRELOAD=/path/to/apitrace/wrappers/glxtrace.so /path/to/application and it will generate a trace named `application.trace` in the current directory. You can specify the written trace filename by setting the `TRACE_FILE` environment variable before running. The `LD_PRELOAD` mechanism should work with most applications. There are some applications, e.g., Unigine Heaven, which global function pointers with the same name as GL entrypoints, living in a shared object that wasn't linked with `-Bsymbolic` flag, so relocations to those globals function pointers get overwritten with the address to our wrapper library, and the application will segfault when trying to write to them. For these applications it is possible to trace by using `glxtrace.so` as an ordinary `libGL.so` and injecting into `LD_LIBRARY_PATH`: ln -s glxtrace.so wrappers/libGL.so ln -s glxtrace.so wrappers/libGL.so.1 ln -s glxtrace.so wrappers/libGL.so.1.2 export LD_LIBRARY_PATH=/path/to/apitrace/wrappers:$LD_LIBRARY_PATH export TRACE_LIBGL=/path/to/real/libGL.so.1 /path/to/application See the `ld.so` man page for more information about `LD_PRELOAD` and `LD_LIBRARY_PATH` environment flags. ### Mac OS X ### Run the application you want to trace as DYLD_LIBRARY_PATH=/path/to/apitrace/wrappers /path/to/application Note that although Mac OS X has an `LD_PRELOAD` equivalent, `DYLD_INSERT_LIBRARIES`, it is mostly useless because it only works with `DYLD_FORCE_FLAT_NAMESPACE=1` which breaks most applications. See the `dyld` man page for more details about these environment flags. Emitting annotations to the trace from GL applications ------------------------------------------------------ You can emit string and frame annotations through the [`GL_GREMEDY_string_marker`](http://www.opengl.org/registry/specs/GREMEDY/string_marker.txt) and [`GL_GREMEDY_frame_terminator`](http://www.opengl.org/registry/specs/GREMEDY/frame_terminator.txt) GL extensions. **apitrace** will advertise and intercept these GL extensions independently of the GL implementation. So all you have to do is to use these extensions when available. For example, if you use [GLEW](http://glew.sourceforge.net/) to dynamically detect and use GL extensions, you could easily accomplish this by doing: void foo() { if (GLEW_GREMEDY_string_marker) { glStringMarkerGREMEDY(0, __FUNCTION__ ": enter"); } ... if (GLEW_GREMEDY_string_marker) { glStringMarkerGREMEDY(0, __FUNCTION__ ": leave"); } } This has the added advantage of working equally well with gDEBugger. Dump GL state at a particular call ---------------------------------- You can get a dump of the bound GL state at call 12345 by doing: glretrace -D 12345 application.trace > 12345.json This is precisely the mechanism the GUI obtains its own state. You can compare two state dumps by doing: apitrace diff-state 12345.json 67890.json Comparing two traces side by side --------------------------------- apitrace diff trace1.trace trace2.trace This works only on Unices, and it will truncate the traces due to performance limitations. Recording a video with FFmpeg ----------------------------- You can make a video of the output by doing glretrace -s - application.trace \ | ffmpeg -r 30 -f image2pipe -vcodec ppm -i pipe: -vcodec mpeg4 -y output.mp4 Advanced usage for OpenGL implementors ====================================== There are several advanced usage examples meant for OpenGL implementors. Regression testing ------------------ These are the steps to create a regression test-suite around **apitrace**: * obtain a trace * obtain reference snapshots, by doing: mkdir /path/to/snapshots/ glretrace -s /path/to/reference/snapshots/ application.trace on reference system. * prune the snapshots which are not interesting * to do a regression test, do: glretrace -c /path/to/reference/snapshots/ application.trace Alternatively, for a HTML summary, use `apitrace diff-images`: glretrace -s /path/to/current/snapshots/ application.trace apitrace diff-images --output summary.html /path/to/reference/snapshots/ /path/to/current/snapshots/ Automated git-bisection ----------------------- With tracecheck.py it is possible to automate git bisect and pinpoint the commit responsible for a regression. Below is an example of using tracecheck.py to bisect a regression in the Mesa-based Intel 965 driver. But the procedure could be applied to any GL driver hosted on a git repository. First, create a build script, named build-script.sh, containing: #!/bin/sh set -e export PATH=/usr/lib/ccache:$PATH export CFLAGS='-g' export CXXFLAGS='-g' ./autogen.sh --disable-egl --disable-gallium --disable-glut --disable-glu --disable-glw --with-dri-drivers=i965 make clean make "$@" It is important that builds are both robust, and efficient. Due to broken dependency discovery in Mesa's makefile system, it was necessary invoke `make clean` in every iteration step. `ccache` should be installed to avoid recompiling unchanged source files. Then do: cd /path/to/mesa export LIBGL_DEBUG=verbose export LD_LIBRARY_PATH=$PWD/lib export LIBGL_DRIVERS_DIR=$PWD/lib git bisect start \ 6491e9593d5cbc5644eb02593a2f562447efdcbb 71acbb54f49089b03d3498b6f88c1681d3f649ac \ -- src/mesa/drivers/dri/intel src/mesa/drivers/dri/i965/ git bisect run /path/to/tracecheck.py \ --precision-threshold 8.0 \ --build /path/to/build-script.sh \ --gl-renderer '.*Mesa.*Intel.*' \ --retrace=/path/to/glretrace \ -c /path/to/reference/snapshots/ \ topogun-1.06-orc-84k.trace The trace-check.py script will skip automatically when there are build failures. The `--gl-renderer` option will also cause a commit to be skipped if the `GL_RENDERER` is unexpected (e.g., when a software renderer or another GL driver is unintentionally loaded due to missing symbol in the DRI driver, or another runtime fault). Side by side retracing ---------------------- In order to determine which draw call a regression first manifests one could generate snapshots for every draw call, using the `-S` option. That is, however, very inefficient for big traces with many draw calls. A faster approach is to run both the bad and a good GL driver side-by-side. The latter can be either a previously known good build of the GL driver, or a reference software renderer. This can be achieved with retracediff.py script, which invokes glretrace with different environments, allowing to choose the desired GL driver by manipulating variables such as `LD_LIBRARY_PATH` or `LIBGL_DRIVERS_DIR`. For example: ./scripts/retracediff.py \ --ref-env LD_LIBRARY_PATH=/path/to/reference/GL/implementation \ -r ./glretrace \ --diff-prefix=/path/to/output/diffs \ application.trace Links ===== About **apitrace**: * [Official mailing list](http://lists.freedesktop.org/mailman/listinfo/apitrace) * [Zack Rusin's blog introducing the GUI](http://zrusin.blogspot.com/2011/04/apitrace.html) * [Jose's Fonseca blog introducing the tool](http://jrfonseca.blogspot.com/2008/07/tracing-d3d-applications.html) Direct3D -------- Open-source: * [Proxy DLL](http://www.mikoweb.eu/index.php?node=21) * [Intercept Calls to DirectX with a Proxy DLL](http://www.codeguru.com/cpp/g-m/directx/directx8/article.php/c11453/) * [Direct3D 9 API Interceptor](http://graphics.stanford.edu/~mdfisher/D3D9Interceptor.html) Closed-source: * [Microsoft PIX](http://msdn.microsoft.com/en-us/library/ee417062.aspx) * [D3DSpy](http://doc.51windows.net/Directx9_SDK/?url=/directx9_sdk/graphics/programmingguide/TutorialsAndSamplesAndToolsAndTips/Tools/D3DSpy.htm): the predecessor of PIX * [AMD GPU PerfStudio](http://developer.amd.com/gpu/PerfStudio/pages/APITraceWindow.aspx) OpenGL ------ Open-source: * [BuGLe](http://www.opengl.org/sdk/tools/BuGLe/) * [GLIntercept](http://code.google.com/p/glintercept/) * [tracy](https://gitorious.org/tracy): OpenGL ES and OpenVG trace, retrace, and state inspection Closed-source: * [gDEBugger](http://www.gremedy.com/products.php) * [glslDevil](http://cumbia.informatik.uni-stuttgart.de/glsldevil/index.html) * [AMD GPU PerfStudio](http://developer.amd.com/gpu/PerfStudio/pages/APITraceWindow.aspx)