View source for B2G/Debugging OpenGL

This page describes how to use the apitrace tool to debug OpenGL calls when using Boot2Gecko.

Special thanks goes out to gw280 who wrote the following: http://www.hackermusings.com/2012/03/debugging-opengl-on-android-without-losing-your-sanity/ which is what most of this is based on.

===Get a copy of apitrace===

The first thing to do is to grab a copy of apitrace.
<pre>
git clone https://github.com/apitrace/apitrace.git
</pre>

The INSTALL.markdown file contains instructions for building. I'll summarize what I did:

===Install the Android NDK===
<pre>
cd /home/work
wget http://dl.google.com/android/ndk/android-ndk-r8-linux-x86.tar.bz2
tar xf android-ndk-r8-linux-x86.tar.bz2
</pre>

===Install cmake and needed Qt packages===
<pre>
sudo apt-get install cmake libqjson-dev libqtwebkit-dev
</pre>

===Build for the host (linux)===
<pre>
cmake -H. -Bbuild
make -C build
</pre>

===Build for the phone===
<pre>
export ANDROID_NDK=/home/work/android-ndk-r8
cmake -DCMAKE_TOOLCHAIN_FILE=cmake/toolchain/android.toolchain.cmake -DANDROID_API_LEVEL=9 -H. -Bbuild-b2g
make -C build-b2g
</pre>

The egltrace.so for the ARM will be found in <tt>libs/armeabi-v7a/egltrace.so</tt>

===Install egltrace.so onto the phone===
<pre>
adb push libs/armeabi-v7a/egltrace.so /data
</pre>

===Run b2g===
I used the following run-apitrace.sh script, which places the trace in /data/egl.trace. If you don't specify <tt>TRACE_FILE</tt> then it wioll be called <tt>firefox.trace</tt> and will be placed in the same directory as the executable, so <tt>/system/b2g/firefox.trace</tt>
<pre>
#!/bin/bash
#set -x

. load-config.sh

ADB=adb
B2G_BIN=/system/b2g/b2g

B2G_PID=`$ADB shell toolbox ps |
         grep "b2g" | awk '{ print \$2; }'`

$ADB shell kill $B2G_PID
$ADB shell stop b2g
$ADB shell TRACE_FILE=/data/egl.trace LD_PRELOAD=/data/egltrace.so LD_LIBRARY_PATH=/system/b2g ${B2G_BIN}
</pre>

===Analyze the captured trace===
<pre>
export EGL_SOFTWARE=true
qapitrace
</pre>

If you choose Trace->Replay then you should see the capture replay the captured trace, and it will then show a thumbnail next to each frame.

Before running Trace->Replay

After running Trace->Replay