apitrace consists of a set of tools to:
-
trace OpenGL, OpenGL ES, Direct3D, and DirectDraw 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.
To obtain apitrace either download the latest binaries for your platform if available, or follow the instructions in INSTALL.markdown to build it yourself. On 64bits Linux and Windows platforms you'll need apitrace binaries that match the architecture (32bits or 64bits) of the application being traced.
Run the application you want to trace as
apitrace trace --api API /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 passing the
--output command line option.
Problems while tracing (e.g, if the application uses calls/parameters unsupported by apitrace) will be reported via stderr output on Unices. On Windows you'll need to run DebugView to view these messages.
Follow the "Tracing manually" instructions below if you cannot obtain a trace.
View the trace with
apitrace dump application.trace
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
You can also tell the GUI to go directly to a specific call
qapitrace application.trace 12345
Several tools take CALLSET arguments, e.g:
apitrace dump --calls CALLSET foo.trace
glretrace -S CALLSET foo.trace
The call syntax is very flexible. Here are a few examples:
-
4one call -
1,2,4,5set of calls -
"1 2 4 5"set of calls (commas are optional and can be replaced with whitespace) -
1-100/2calls 1, 3, 5, ..., 99 -
1-1000/drawall draw calls between 1 and 1000 -
1-1000/fboall fbo changes between calls 1 and 1000 -
frameall calls at end of frames -
@foo.txtread call numbers fromfoo.txt, using the same syntax as above
On 64 bits systems, you'll need to determine ether the application is 64 bits or 32 bits. This can be done by doing
file /path/to/application
But beware of wrapper shell scripts -- what matters is the architecture of the main process.
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.
To trace the application inside gdb, invoke gdb as:
gdb --ex 'set exec-wrapper env LD_PRELOAD=/path/to/glxtrace.so' --args /path/to/application
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.
When tracing third-party applications, you can identify the target application's main executable, either by:
-
right clicking on the application's icon in the Start Menu, choose Properties, and see the Target field;
-
or by starting the application, run Windows Task Manager (taskmgr.exe), right click on the application name in the Applications tab, choose Go To Process, note the highlighted Image Name, and search it on
C:\Program FilesorC:\Program Files (x86).
On 64 bits Windows, you'll need to determine ether the application is a 64 bits
or 32 bits. 32 bits applications will have a *32 suffix in the Image Name
column of the Processes tab of Windows Task Manager window.
Copy the appropriate opengl32.dll, d3d8.dll, or d3d9.dll from the
wrappers directory to the directory with the application you want to trace.
Then run the application as usual.
You can specify the written trace filename by setting the TRACE_FILE
environment variable before running.
From OpenGL applications you can embed annotations in the trace file through the
GL_GREMEDY_string_marker
and
GL_GREMEDY_frame_terminator
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 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.
From OpenGL ES applications you can embed annotations in the trace file through the
GL_EXT_debug_marker
extension.
For Direct3D applications you can follow the same procedure used for instrumenting an application for PIX
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
apitrace diff trace1.trace trace2.trace
This works only on Unices, and it will truncate the traces due to performance limitations.
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
You can make a smaller trace by doing:
apitrace trim --callset 100-1000 -o trimed.trace applicated.trace
If you need precise control over which calls to trim you can specify the individual call numbers a plaintext file, as described in the 'Call sets' section above.
There are several advanced usage examples meant for OpenGL implementors.
These are the steps to create a regression test-suite around apitrace:
-
obtain a trace
-
obtain reference snapshots, by doing on a reference system:
mkdir /path/to/reference/snapshots/ glretrace -s /path/to/reference/snapshots/ application.trace -
prune the snapshots which are not interesting
-
to do a regression test, do:
glretrace -c /path/to/reference/snapshots/ application.traceAlternatively, for a HTML summary, use
apitrace diff-images:glretrace -s /path/to/test/snapshots/ application.trace apitrace diff-images --output summary.html /path/to/reference/snapshots/ /path/to/test/snapshots/
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).
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, LIBGL_DRIVERS_DIR, or
TRACE_LIBGL.
For example, on Linux:
./scripts/retracediff.py \
--ref-env LD_LIBRARY_PATH=/path/to/reference/GL/implementation \
--retrace /path/to/glretrace \
--diff-prefix=/path/to/output/diffs \
application.trace
Or on Windows:
python scripts\retracediff.py --retrace \path\to\glretrace.exe --ref-env TRACE_LIBGL=\path\to\reference\opengl32.dll application.trace
About apitrace:
Open-source:
Closed-source:
-
- D3DSpy: the predecessor of PIX
Open-source:
-
tracy: OpenGL ES and OpenVG trace, retrace, and state inspection
Closed-source: