Hash :
39f7e9b4
Author :
Date :
2021-10-20T21:51:27
Doc: Clarify purpose of listed build options in DevSetup.md This file lists a number of commonly overriden build options for development or special platforms, but was mistakenly taken as a set of "recommended" options. Bug: angleproject:1944 Change-Id: Ia50b45724797d5ab071936997b485f9f80a72704 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3234079 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>
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_tools is in your path as it provides ninja for compilation. download_from_google_storage --config to login to Google Storage. On Windows:
DEPOT_TOOLS_WIN_TOOLCHAIN=0 in your environment if you are not a Googler. On Linux:
install-build-deps.sh below). On MacOS:
gclient sync. Obtain this authorization via cipd auth-login
and following the instructions. git clone https://chromium.googlesource.com/angle/angle
cd angle
python scripts/bootstrap.py
gclient sync
git checkout main
If you’re contributing code, you will also need to set up the commit-msg hook. See ContributingCode#getting-started-with-gerrit for more detailed instructions.
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. The default build options build ANGLE with clang and in release mode.
Often, the default options are the desired ones, but they can be changed by running
gn args out/Debug. Some options that are commonly overriden for development are:
is_component_build = false (links dependencies into the build targets)
target_cpu = "x86" (default is "x64")
is_clang = false (NOT RECOMMENDED) (to use system default compiler instead of clang)
is_debug = false (for release builds. is_debug = true is the default)
angle_assert_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.
Setting is_component_build = false is highly recommended to support moving libEGL.dll and libGLESv2.dll to an
application’s directory and being self-contained, instead of depending on other DLLs (d3dcompiler_47.dll is still
needed for the Direct3D backend).
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.
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 out/Debug/angle-debug.sln:
gn gen out/Debug --sln=angle-debug --ide=vs2019
In Visual Studio:
out/Debug/angle-debug.sln. autoninja from the command line to build.
Once the build completes all ANGLE libraries, tests, and samples will be located in out/Debug.
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 extensions/EGL_ANGLE_platform_angle_*.txt and
examples of its use can be seen in the ANGLE samples and tests, particularly util/EGLWindow.cpp.
To change the default D3D backend:
src/libANGLE/renderer/d3d/DisplayD3D.cpp ANGLE_DEFAULT_D3D11 near 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: angle_enable_d3d9 angle_enable_d3d11 angle_enable_gl angle_enable_metal angle_enable_null angle_enable_vulkan angle_enable_essl angle_enable_glsl On Windows:
include folder to provide access to the standard Khronos EGL and GLES2 header files. libEGL.lib and libGLESv2.lib found in the build output directory (see Building ANGLE). libEGL.lib file and libGLESv2.lib file to Additional Dependencies, separated by a semicolon. libEGL.dll and libGLESv2.dll from the build output directory (see Building ANGLE) into your application folder. On Linux and MacOS, either:
libGLESv2 and libEGL dlopen to load the OpenGL ES and EGL entry points at runtime.
In addition to OpenGL ES and EGL libraries, ANGLE also provides a GLSL ES
translator. The translator targets various back-ends, including HLSL, GLSL
for desktop and mobile, SPIR-V and Metal SL. To build the translator, build
the angle_shader_translator target. Run the translator binary without
arguments to see a usage message.
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 ANGLE shader_translator
sample demos basic C++ API usage. To translate a GLSL ES shader, call the following
functions in the same order:
sh::Initialize() initializes the translator library and must be called only once from each process using the translator. sh::ContructCompiler() creates a translator object for vertex or fragment shader. sh::Compile() translates the given shader. sh::Destruct() destroys the given translator. sh::Finalize() shuts down the translator library and must be called only once from each process using the translator.
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# 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](http://git-scm.com/documentation).
### Required Tools
On all platforms:
* [depot_tools](https://commondatastorage.googleapis.com/chrome-infra-docs/flat/depot_tools/docs/html/depot_tools_tutorial.html#_setting_up)
* 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.
* For Googlers, run `download_from_google_storage --config` to login to Google Storage.
On Windows:
* ***IMPORTANT: Set `DEPOT_TOOLS_WIN_TOOLCHAIN=0` in your environment if you are not a Googler.***
* Install [Visual Studio Community 2019](https://visualstudio.microsoft.com/vs/)
* Install the [Windows 10 SDK, latest version](https://developer.microsoft.com/en-us/windows/downloads/windows-10-sdk).
* You can install it through Visual Studio Installer if available.
* Required for GN-generated Visual Studio projects, the Debug runtime for D3D11, and the D3D Compiler DLL.
* (optional) See the [Chromium Windows build instructions](https://chromium.googlesource.com/chromium/src/+/main/docs/windows_build_instructions.md) for more info.
On Linux:
* Dependencies will be handled later (see `install-build-deps.sh` below).
On MacOS:
* [XCode](https://developer.apple.com/xcode/) for Clang and development files.
* For Googlers on MacOS, you'll first need authorization to download macOS SDK's from Chromium
servers before running `gclient sync`. Obtain this authorization via `cipd auth-login`
and following the instructions.
### Getting the source
```
git clone https://chromium.googlesource.com/angle/angle
cd angle
python scripts/bootstrap.py
gclient sync
git checkout main
```
If you're contributing code, you will also need to set up the commit-msg hook. See [ContributingCode#getting-started-with-gerrit](ContributingCode.md#getting-started-with-gerrit) for more detailed instructions.
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. The default build options build ANGLE with clang and in release mode.
Often, the default options are the desired ones, but they can be changed by running
`gn args out/Debug`. Some options that are commonly overriden for development are:
```
is_component_build = false (links dependencies into the build targets)
target_cpu = "x86" (default is "x64")
is_clang = false (NOT RECOMMENDED) (to use system default compiler instead of clang)
is_debug = false (for release builds. is_debug = true is the default)
angle_assert_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.
Setting `is_component_build = false` is highly recommended to support moving libEGL.dll and libGLESv2.dll to an
application's directory and being self-contained, instead of depending on other DLLs (d3dcompiler_47.dll is still
needed for the Direct3D backend).
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 Goma (Google employees only)
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 10*numCores to 20*numCores. If you run autoninja then
it will automatically pass an appropriate -j value to ninja for goma or not.
```
$ autoninja -C out\Debug
```
### Building and Debugging 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
See the Android specific [documentation](DevSetupAndroid.md#ANGLE-for-Android).
## 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 its specification in
`extensions/EGL_ANGLE_platform_angle.txt` and `extensions/EGL_ANGLE_platform_angle_*.txt` and
examples of its 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 remove any backend entirely:
1. Run `gn args <path/to/build/dir>`
2. Set the appropriate variable to `false`. Options are:
- `angle_enable_d3d9`
- `angle_enable_d3d11`
- `angle_enable_gl`
- `angle_enable_metal`
- `angle_enable_null`
- `angle_enable_vulkan`
- `angle_enable_essl`
- `angle_enable_glsl`
### 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](#building-with-visual-studio)).
* 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](#building-with-visual-studio)) into your application folder.
4. Code your application to the Khronos [OpenGL ES 2.0](http://www.khronos.org/registry/gles/) and [EGL 1.4](http://www.khronos.org/registry/egl/) 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 Translator
In addition to OpenGL ES and EGL libraries, ANGLE also provides a GLSL ES
translator. The translator targets various back-ends, including HLSL, GLSL
for desktop and mobile, SPIR-V and Metal SL. To build the translator, build
the `angle_shader_translator` target. Run the translator binary without
arguments to see a usage message.
### Source and Building
The translator code is included with ANGLE but fully independent; it resides
in [`src/compiler`](../src/compiler). Follow the steps above for
[getting and building ANGLE](#getting-the-source) to build the translator on
the platform of your choice.
### Usage
The ANGLE [`shader_translator`](../samples/shader_translator/shader_translator.cpp)
sample demos basic C++ API usage. To translate a GLSL ES shader, call the following
functions in the same order:
* `sh::Initialize()` initializes the translator library and must be called only once from each process using the translator.
* `sh::ContructCompiler()` creates a translator object for vertex or fragment shader.
* `sh::Compile()` translates the given shader.
* `sh::Destruct()` destroys the given translator.
* `sh::Finalize()` shuts down the translator library and must be called only once from each process using the translator.