There are many ways to debug ANGLE using generic or platform-dependent tools. Here is a list of tips on how to use them.
Apitrace captures traces of OpenGL commands for later analysis,
allowing us to see how ANGLE translates OpenGL ES commands. In order to capture the trace, it
inserts a driver shim using LD_PRELOAD that records the command and then forwards it to the OpenGL
driver.
The problem with ANGLE is that it exposes the same symbols as the OpenGL driver so apitrace captures the entry point calls intended for ANGLE and reroutes them to the OpenGL driver. In order to avoid this problem, use the following:
- Link your application against the static ANGLE libraries (libGLESv2_static and libEGL_static) so they don't get shadowed by apitrace's shim.
- Ask apitrace to explicitly load the driver instead of using a dlsym on the current module.
Otherwise apitrace will use ANGLE's symbols as the OpenGL driver entrypoint (causing infinite
recursion). To do this you must point an environment variable to your GL driver. For example:
export TRACE_LIBGL=/usr/lib/libGL.so.1. You can find your libGL withldconfig -p | grep libGL. - Link ANGLE against libGL instead of dlsyming the symbols at runtime; otherwise ANGLE won't use
the replaced driver entry points. This is done with the gn arg
angle_link_glx = true.
If you follow these steps, apitrace will work correctly aside from a few minor bugs like not being able to figure out what the default framebuffer size is if there is no glViewport command.
For example, to trace a run of hello_triangle, assuming the apitrace executables are in $PATH:
gn args out/Debug # add "angle_link_glx = true"
# edit samples/BUILD.gn and append "_static" to "angle_util", "libEGL", "libGLESv2"
ninja -C out/Debug
export TRACE_LIBGL="/usr/lib/libGL.so.1" # may require a different path
apitrace trace -o mytrace ./out/Debug/hello_triangle
qapitrace mytrace
GAPID can be used to capture trace of Vulkan commands on Linux.
When capturing traces of gtest based tests built inside Chromium checkout, make sure to run the
tests with --single-process-tests argument.
GAPID can be used to capture a trace of the Vulkan or OpenGL ES command stream on Android. For it to work, ANGLE's libraries must have different names from the system OpenGL libraries. This is done with the gn arg:
angle_libs_suffix = "_ANGLE_DEV"
All
NativeTest
based tests share the same activity name, org.chromium.native_test.NativeUnitTestNativeActivity.
Thus, prior to capturing your test trace, the specific test APK must be installed on the device.
When you build the test, a test launcher is generated, for example,
./out/Release/bin/run_angle_end2end_tests. The best way to install the APK is to run this test
launcher once.
In GAPID's "Capture Trace" dialog, "Package / Action:" should be:
android.intent.action.MAIN:org.chromium.native_test/org.chromium.native_test.NativeUnitTestNativeActivity
The mandatory extra intent
argument for starting the
activity is org.chromium.native_test.NativeTest.StdoutFile. Without it the test APK crashes. Test
filters can be specified via either the org.chromium.native_test.NativeTest.CommandLineFlags or
the org.chromium.native_test.NativeTest.Shard argument. Example "Intent Arguments:" values in
GAPID's "Capture Trace" dialog:
-e org.chromium.native_test.NativeTest.StdoutFile /sdcard/chromium_tests_root/out.txt -e org.chromium.native_test.NativeTest.CommandLineFlags "--gtest_filter=*ES2_VULKAN"
or
-e org.chromium.native_test.NativeTest.StdoutFile /sdcard/chromium_tests_root/out.txt --esal org.chromium.native_test.NativeTest.Shard RendererTest.SimpleOperation/ES2_VULKAN,SimpleOperationTest.DrawWithTexture/ES2_VULKAN
An application running through ANGLE can confuse RenderDoc, as RenderDoc hooks to EGL and ends up tracing the calls the application makes, instead of the calls ANGLE makes to its backend. As ANGLE is a special case, there's little support for it by RenderDoc, though there are workarounds.
On Windows, RenderDoc supports setting the environment variable RENDERDOC_HOOK_EGL to 0 to avoid
this issue.
On Linux, there is no supported workaround by RenderDoc. See this issue. To capture Vulkan traces, the workaround is to build RenderDoc without GL(ES) support.
Building RenderDoc is straightforward. However, here are a few instructions to keep in mind.
# Install dependencies based on RenderDoc document. Here are some packages that are unlikely to be already installed:
$ sudo apt install libxcb-keysyms1-dev python3-dev qt5-qmake libqt5svg5-dev libqt5x11extras5-dev
# Inside the RenderDoc directory:
$ cmake -DCMAKE_BUILD_TYPE=Release -Bbuild -H. -DENABLE_GLES=OFF -DENABLE_GL=OFF
# QT_SELECT=5 is necessary if your distribution doesn't default to Qt5
$ QT_SELECT=5 make -j -C build
# Run RenderDoc from the build directory:
$ ./build/bin/qrenderdoc
If your distribution does not provide a recent Vulkan SDK package, you would need to manually install that. This script tries to perform this installation as safely as possible. It would overwrite the system package's files, so follow at your own risk. Place this script just above the extracted SDK directory.
#! /bin/bash
if [ $# -lt 1 ]; then
echo "Usage: $0 <version>"
exit 1
fi
ver=$1
if [ ! -d "$ver" ]; then
echo "$ver is not a directory"
fi
# Verify everything first
echo "Verifying files..."
echo "$ver"/x86_64/bin/vulkaninfo
test -f "$ver"/x86_64/bin/vulkaninfo || exit 1
echo "$ver"/x86_64/etc/explicit_layer.d/
test -d "$ver"/x86_64/etc/explicit_layer.d || exit 1
echo "$ver"/x86_64/lib/
test -d "$ver"/x86_64/lib || exit 1
echo "Verified. Performing copy..."
echo sudo cp "$ver"/x86_64/bin/vulkaninfo /usr/bin/vulkaninfo
sudo cp "$ver"/x86_64/bin/vulkaninfo /usr/bin/vulkaninfo
echo sudo cp "$ver"/x86_64/etc/explicit_layer.d/* /etc/explicit_layer.d/
sudo cp "$ver"/x86_64/etc/explicit_layer.d/* /etc/explicit_layer.d/
echo sudo rm /usr/lib/x86_64-linux-gnu/libvulkan.so*
sudo rm /usr/lib/x86_64-linux-gnu/libvulkan.so*
echo sudo cp -P "$ver"/x86_64/lib/lib* /usr/lib/x86_64-linux-gnu/
sudo cp -P "$ver"/x86_64/lib/lib* /usr/lib/x86_64-linux-gnu/
echo "Done."
If you are on Linux, make sure not to use the build done in the previous section. The GL renderer disabled in the previous section is actually needed in this section.
Define the following environment variables, for example in .bashrc (values are examples):
export JAVA_HOME=/usr/local/buildtools/java/jdk
export ANDROID_SDK=$HOME/chromium/src/third_party/android_sdk/public
export ANDROID_NDK=$HOME/chromium/src/third_party/android_ndk
export ANDROID_NDK_HOME=$HOME/chromium/src/third_party/android_ndk
In the renderdoc directory, create Android builds of RenderDoc:
mkdir build-android-arm32
cd build-android-arm32/
cmake -DBUILD_ANDROID=On -DANDROID_ABI=armeabi-v7a ..
make -j
cd ../
mkdir build-android-arm64
cd build-android-arm64/
cmake -DBUILD_ANDROID=On -DANDROID_ABI=arm64-v8a ..
make -j
cd ../
Note that you need both arm32 and arm64 builds even if working with an arm64 device. See RenderDoc's documentation for more information.
When you run RenderDoc, choose the "Replay Context" from the bottom-left part of the UI (defaults to Local). When selecting the device, you should see the RenderDoc application running.
In ANGLE itself, make sure you add a suffix for its names to be different from the system's. Add this to gn args:
angle_libs_suffix = "_ANGLE_DEV"
Next, you need to install an ANGLE test apk. When you build the test, a test launcher is generated,
for example, ./out/Release/bin/run_angle_end2end_tests. The best way to install the APK is to run
this test launcher once.
In RenderDoc, use org.chromium.native_test as the Executable Path, and provide the following
arguments:
-e org.chromium.native_test.NativeTest.StdoutFile /sdcard/chromium_tests_root/out.txt -e org.chromium.native_test.NativeTest.CommandLineFlags "--gtest_filter=*ES2_VULKAN"
Note that in the above, only a single command line argument is supported with RenderDoc. If testing
dEQP on a non-default platform, the easiest way would be to modify GetDefaultAPIName() in
src/tests/deqp_support/angle_deqp_gtest.cpp (and avoid --use-angle=X).