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.
ANGLE uses git for version control. Helpful documentation can be found at http://git-scm.com/documentation.
On all platforms:
depot_toolsis in your path as it provides ninja for compilation.
download_from_google_storage --configto login to Google Storage.
DEPOT_TOOLS_WIN_TOOLCHAIN=0in your environment if you are not a Googler.
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:
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
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.
depot_tools is in your path as it provides ninja.
In addition, Google employees should use goma, a distributed compilation system. Detailed information is available internally but the relevant gn arg is:
use_goma = true
To get any benefit from goma it is important to pass a large -j value to ninja. A good default is 10numCores to 20numCores. If you run autoninja then it will automatically pass an appropriate -j value to ninja for goma or not.
$ autoninja -C out\Debug
To generate the Visual Studio solution in
gn gen out/Debug --sln=angle-debug --ide=vs2019
In Visual Studio:
autoninjafrom the command line to build.
Once the build completes all ANGLE libraries, tests, and samples will be located in
See the Android specific documentation.
This sections describes how to use ANGLE to build an OpenGL ES application.
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 its specification in
extensions/EGL_ANGLE_platform_angle_*.txt and examples of its use can be seen in the ANGLE samples and tests, particularly
To change the default D3D backend:
ANGLE_DEFAULT_D3D11near the head of the file, and set it to your preference.
To remove any backend entirely:
gn args <path/to/build/dir>
false. Options are:
includefolder to provide access to the standard Khronos EGL and GLES2 header files.
libGLESv2.libfound in the build output directory (see Building ANGLE).
libGLESv2.libfile to Additional Dependencies, separated by a semicolon.
libGLESv2.dllfrom the build output directory (see Building ANGLE) into your application folder.
On Linux and MacOS, either:
dlopento load the OpenGL ES and EGL entry points at runtime.
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.
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.
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.