angle/doc/DevSetup.md

ANGLE Development

ANGLE provides OpenGL ES 3.1 and EGL 1.5 libraries and tests. You can use these to build and run OpenGL ES applications on Windows, Linux, Mac and Android.

Development setup

Version Control

ANGLE uses git for version control. Helpful documentation can be found at http://git-scm.com/documentation.

Required Tools

On all platforms:

• depot_tools
  • Required to download dependencies (with gclient), generate build files (with GN), and compile ANGLE (with ninja).
  • Ensure depot_tools is in your path as it provides ninja for compilation.

On Windows:

• IMPORTANT: Set DEPOT_TOOLS_WIN_TOOLCHAIN=0 in your environment if you are not a Googler.
• Visual Studio Community 2019
• Windows 10 Standalone SDK version 10.0.17134 exactly.
  • Comes with additional features that aid development, such as the Debug runtime for D3D11. Required for the D3D Compiler DLL.
• (optional) Cygwin's Bison, flex, and patch
  • This is only required if you need to modify GLSL ES grammar files (glslang.l and glslang.y under src/compiler/translator, or ExpressionParser.y and Tokenizer.l in src/compiler/preprocessor).
• (optional) See the Chromium Windows build instructions for more info.

On Linux:

• Install package dependencies by running install-build-deps.sh later on.
• Bison and flex are not needed as we only support generating the translator grammar on Windows.

On MacOS:

• XCode for Clang and development files.
• Bison and flex are not needed as we only support generating the translator grammar on Windows.

Getting the source

git clone https://chromium.googlesource.com/angle/angle
cd angle
python scripts/bootstrap.py
gclient sync
git checkout master

On Linux only, you need to install all the necessary dependencies before going further by running this command:

./build/install-build-deps.sh

After this completes successfully, you are ready to generate the ninja files:

gn gen out/Debug

On Windows only, ensure you set DEPOT_TOOLS_WIN_TOOLCHAIN=0 in your environment (if you are not a Googler).

GN will generate ninja files. To change the default build options run gn args out/Debug. Some commonly used options are:

target_cpu = "x86"        (default is "x64")
is_clang = false          (to use system default compiler instead of clang)
is_debug = true           (enable debugging, true is the default)
dcheck_always_on = true   (enable release asserts and debug layers)

For a release build run gn args out/Release and set is_debug = false.

On Windows, you can build for the Universal Windows Platform (UWP) by setting target_os = "winuwp" in the args.

For more information on GN run gn help.

Ninja can be used to compile on all platforms with one of the following commands:

autoninja -C out/Debug
autoninja -C out/Release

Ninja automatically calls GN to regenerate the build files on any configuration change.

Ensure depot_tools is in your path as it provides ninja.

Building with Visual Studio

To generate the Visual Studio solution in out/Debug/angle-debug.sln:

gn gen out/Debug --sln=angle-debug --ide=vs2019

In Visual Studio:

1. Open the ANGLE solution file out/Debug/angle-debug.sln.
2. It is recommended you still use autoninja from the command line to build.
3. If you do want to build in the solution, "Build Solution" is not functional with GN. Build one target at a time.

Once the build completes all ANGLE libraries, tests, and samples will be located in out/Debug.

Building ANGLE for Android

Building ANGLE for Android is heavily dependent on the Chromium toolchain. It is not currently possible to build ANGLE for Android without a Chromium checkout. See http://anglebug.com/2344 for more details on why. Please follow the steps in Checking out and building Chromium for Android. This must be done on Linux, the only platform that Chromium for Android supports. Name your output directories out/Debug and out/Release, because Chromium GPU tests look for browser binaries in these folders. Replacing out with other names seems to be OK when working with multiple build configurations. It's best to use a build configuration of some Android bot on GPU.FYI waterfall. Look for generate_build_files step output of that bot. Remove goma_dir flag. For example, these are the build flags from Nexus 5X bot:

build_angle_deqp_tests = true
dcheck_always_on = true
ffmpeg_branding = "Chrome"
is_component_build = false
is_debug = false
proprietary_codecs = true
symbol_level = 1
target_cpu = "arm64"          # Nexus 5X is 64 bit, remove this on 32 bit devices
target_os = "android"
use_goma = true               # Remove this if you don't have goma

Additional flags to build the Vulkan backend, enable only if running on Android O or higher:

android32_ndk_api_level = 26
android64_ndk_api_level = 26

These ANGLE targets are supported: ninja -C out/Release translator libEGL libGLESv2 angle_unittests angle_end2end_tests angle_white_box_tests angle_deqp_gles2_tests angle_deqp_gles3_tests angle_deqp_egl_tests angle_perftests angle_white_box_perftests

In order to run ANGLE tests, prepend bin/run_ to the test name, for example: ./out/Release/bin/run_angle_unittests. Additional details are in Android Test Instructions.

dEQP Note: Running the tests not using the test runner is tricky, but is necessary in order to get a complete TestResults.qpa from the dEQP tests (since the runner shards the tests, only the results of the last shard will be available when using the test runner). First, use the runner to install the APK, test data and test expectations on the device. After the tests start running, the test runner can be stopped with Ctrl+C. Then, run

adb shell am start -a android.intent.action.MAIN -n org.chromium.native_test/.NativeUnitTestNativeActivity -e org.chromium.native_test.NativeTest.StdoutFile /sdcard/chromium_tests_root/out.txt

After the tests finish, get the results with

adb pull /sdcard/chromium_tests_root/third_party/angle/third_party/deqp/src/data/TestResults.qpa .

Note: this location might change, one can double-check with adb logcat -d | grep qpa.

In order to run GPU telemetry tests, build chrome_public_apk target. Then follow GPU Testing doc, using --browser=android-chromium argument. Make sure to set your CHROMIUM_OUT_DIR environment variable, so that your browser is found, otherwise the stock one will run.

Also, follow How to build ANGLE in Chromium for dev to work with Top of Tree ANGLE in Chromium.

Application Development with ANGLE

This sections describes how to use ANGLE to build an OpenGL ES application.

Choosing a Backend

ANGLE can use a variety of backing renderers based on platform. On Windows, it defaults to D3D11 where it's available, or D3D9 otherwise. On other desktop platforms, it defaults to GL. On mobile, it defaults to GLES.

ANGLE provides an EGL extension called EGL_ANGLE_platform_angle which allows uers to select which renderer to use at EGL initialization time by calling eglGetPlatformDisplayEXT with special enums. Details of the extension can be found in it's specification in extensions/ANGLE_platform_angle.txt and extensions/ANGLE_platform_angle_*.txt and examples of it's use can be seen in the ANGLE samples and tests, particularly util/EGLWindow.cpp.

To change the default D3D backend:

1. Open src/libANGLE/renderer/d3d/DisplayD3D.cpp
2. Locate the definition of ANGLE_DEFAULT_D3D11 near the head of the file, and set it to your preference.

To Use ANGLE in Your Application

On Windows:

1. Configure your build environment to have access to the include folder to provide access to the standard Khronos EGL and GLES2 header files.

• For Visual C++
  • Right-click your project in the Solution Explorer, and select Properties.
  • Under the Configuration Properties branch, click C/C++.
  • Add the relative path to the Khronos EGL and GLES2 header files to Additional Include Directories.

2. Configure your build environment to have access to libEGL.lib and libGLESv2.lib found in the build output directory (see Building ANGLE).

• For Visual C++
  • Right-click your project in the Solution Explorer, and select Properties.
  • Under the Configuration Properties branch, open the Linker branch and click Input.
  • Add the relative paths to both the libEGL.lib file and libGLESv2.lib file to Additional Dependencies, separated by a semicolon.

3. Copy libEGL.dll and libGLESv2.dll from the build output directory (see Building ANGLE) into your application folder.
4. Code your application to the Khronos OpenGL ES 2.0 and EGL 1.4 APIs.

On Linux and MacOS, either:

• Link you application against libGLESv2 and libEGL
• Use dlopen to load the OpenGL ES and EGL entry points at runtime.

GLSL ES to GLSL Translator

In addition to OpenGL ES 2.0 and EGL 1.4 libraries, ANGLE also provides a GLSL ES to GLSL translator. This is useful for implementing OpenGL ES emulators on top of desktop OpenGL.

Source and Building

The translator code is included with ANGLE but fully independent; it resides in src/compiler. Follow the steps above for getting and building ANGLE to build the translator on the platform of your choice.

Usage

The basic usage is shown in essl_to_glsl sample under samples/translator. To translate a GLSL ES shader, following functions need to be called in the same order:

• ShInitialize() initializes the translator library and must be called only once from each process using the translator.
• ShContructCompiler() creates a translator object for vertex or fragment shader.
• ShCompile() translates the given shader.
• ShDestruct() destroys the given translator.
• ShFinalize() shuts down the translator library and must be called only once from each process using the translator.