ANGLE Development

ANGLE provides OpenGL ES 2.0 and EGL 1.4 libraries and dlls. You can use these to build and run OpenGL ES 2.0 applications on Windows.

Development setup

Version Control

ANGLE uses git for version control. If you are not familiar with git, helpful documentation can be found at http://git-scm.com/documentation.

Required Tools

On all platforms:

  • GN is the supported build system. GYP is deprecated and support will be removed in the future but instructions are available.
  • Clang will be set up by the build system and used by default. See below for platform-specific compiler choices.
  • depot_tools
    • Required to generate projects and build files, contribute patches, run the unit tests or build the shader compiler on non-Windows systems.

On Windows:

  • Visual Studio Community 2017 Update 3.2
    • Put is_clang = false in your gn args to compile with the Microsoft Visual C++ compiler instead of clang.
    • See the Chromium Windows build instructions for more info.
    • Required for the packaged Windows 10 SDK.
  • Windows 10 Standalone SDK version 10.0.15063 exactly
    • Comes with additional features that aid development, such as the Debug runtime for D3D11. Required for the D3D Compiler DLL.
  • Cygwin's Bison, flex, and patch (optional)
    • 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). Use the latest versions of bison, flex and patch from the 64-bit cygwin distribution.
  • Non-googlers need to set DEPOT_TOOLS_WIN_TOOLCHAIN environment variable to 0.

On Linux:

  • Development packages for OpenGL, X11 and libpci
  • 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
gn gen out/Debug

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

target_cpu = "x64"  (or "x86")
is_clang = false    (to use system default compiler instead of clang)
is_debug = true     (enable debugging, true is the default)

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

For more information on GN run gn help.

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

ninja -C out/Debug
ninja -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

Run scripts/msvs_projects.py to generate a Visual Studio solution in out/sln/ANGLE.sln. This script runs GN and consolidates all the targets in out into a single meta-solution.

In Visual Studio:

  1. Open the ANGLE solution file out/sln/ANGLE.sln.
  2. The configurations found in your out directory will be mapped to configurations in the configuration manager. For compatibility reasons all configurations are listed as 64-bits.
  3. Right click the “all” solution and select build. “Build Solution” is not functional with GN; instead build one target at a time." Once the build completes the output directory for your selected configuration (e.g. out/Release_x64) will contain the required libraries and dlls to build and run an OpenGL ES 2.0 application. ANGLE executables (tests and samples) are under out/sln.

Building ANGLE for Android

At present it is not possible to build standalone ANGLE for Android but it can be built within a Chromium checkout. Since ANGLE has converted to GN a standalone build should be possible. For now 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

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 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.

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/deqp/src/data/TestResults.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 D3D Backend

ANGLE can use either a backing renderer which uses D3D11 on systems where it is available, or a D3D9-only renderer.

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_d3d.txt and examples of it’s use can be seen in the ANGLE samples and tests, particularly util/EGLWindow.cpp.

By default, ANGLE will use a D3D11 renderer. To change the default:

  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.
  1. 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.
  1. Copy libEGL.dll and libGLESv2.dll from the build output directory (see Building ANGLE) into your application folder.
  2. 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.