Hash :
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        Author :
  
        
        Date :
2016-05-10T17:12:40
        
      
Add build instructions for Linux and MacOS BUG=angleproject:1368 Change-Id: I2a0852399cdf04192d7e1d11b33b2103aa173354 Reviewed-on: https://chromium-review.googlesource.com/344003 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Corentin Wallez <cwallez@chromium.org>
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.
ANGLE uses git for version control. If you are not familiar with git, helpful documentation can be found at http://git-scm.com/documentation.
On all platforms:
On Windows:
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.  On Linux:
On MacOS:
Set the following environment variables as needed:
On Windows:
GYP_GENERATORS to msvs (other options include ninja and make)  GYP_DEFINES to windows_sdk_path=YOUR_WIN_SDK_INSTALL_DIR if you did not install the Windows 8.1 SDK in the default location.  GYP_MSVS_VERSION to 2015  On Linux and MacOS:
GYP_GENERATORS to ninja (defaults to ‘make’ that pollutes your source directory)  Download the ANGLE source by running the following commands:
git clone https://chromium.googlesource.com/angle/angle
cd angle
python scripts/bootstrap.py
gclient sync
git checkout master
GYP will generate the project files, if you update ANGLE or make a change to the projects, they can be regenerated by executing gclient runhooks.
On Windows GYP will generate the main VS2015 solution file as build/ANGLE.sln. For generating a Windows Store version of ANGLE view the Windows Store instructions.
On Linux and MacOS, GYP will generate the out/Debug and out/Release directories.
Release_Win32, located next to the solution file) will contain the required libraries and dlls to build and run an OpenGL ES 2.0 application.  
Run ninja -C out/Debug or ninja -C out/Release. Ninja is provided by depot_tools so make sure you set up your PATH correctly.
Once the build completes, the out/Debug or out/Release directories will contain the .so or .dylib libraries and test binaries.
This sections describes how to use ANGLE to build an OpenGL ES application.
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:
src/libANGLE/renderer/d3d/DisplayD3D.cpp  ANGLE_DEFAULT_D3D11 near the head of the file, and set it to your preference.  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 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 fully independent of the rest of ANGLE code and resides in src/compiler.  It is cross-platform and build files for operating systems other than Windows can be generated by following the Generating project files steps above.
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.  
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# 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](http://git-scm.com/documentation).
### Required Tools
On all platforms:
 * [depot_tools](http://dev.chromium.org/developers/how-tos/install-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 2015 Update 2](http://www.visualstudio.com/downloads/download-visual-studio-vs)
     Required to build ANGLE on Windows and for the packaged Windows 8.1 SDK.
 * [Cygwin's Bison, flex, and patch](https://cygwin.com/setup-x86_64.exe) (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.
On Linux:
 * The GCC or Clang compilers
 * 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](https://developer.apple.com/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
Set the following environment variables as needed:
On Windows:
 * `GYP_GENERATORS` to `msvs` (other options include `ninja` and `make`)
 * `GYP_DEFINES` to `windows_sdk_path=YOUR_WIN_SDK_INSTALL_DIR` if you did not install the Windows 8.1 SDK in the default location.
 * `GYP_MSVS_VERSION` to `2015`
On Linux and MacOS:
 * `GYP_GENERATORS` to `ninja` (defaults to 'make' that pollutes your source directory)
Download the ANGLE source by running the following commands:
```
git clone https://chromium.googlesource.com/angle/angle
cd angle
python scripts/bootstrap.py
gclient sync
git checkout master
```
GYP will generate the project files, if you update ANGLE or make a change to the projects, they can be regenerated by executing `gclient runhooks`.
On Windows GYP will generate the main VS2015 solution file as build/ANGLE.sln. For generating a Windows Store version of ANGLE view the [Windows Store instructions](doc/BuildingAngleForWindowsStore.md).
On Linux and MacOS, GYP will generate the `out/Debug` and `out/Release` directories.
### Building ANGLE on Windows
 1. Open one of the ANGLE Visual Studio solution files (see [Getting the source](DevSetup.md#Development-setup-Getting-the-source)).
 2. Select Build -> Configuration Manager
 3. In the "Active solution configuration:" drop down, select the desired configuration (eg. Release), and close the Configuration Manager.
 4. Select Build -> Build Solution.
Once the build completes, the output directory for your selected configuration (eg. `Release_Win32`, located next to the solution file) will contain the required libraries and dlls to build and run an OpenGL ES 2.0 application.
### Building ANGLE on Linux and MacOS
Run `ninja -C out/Debug` or `ninja -C out/Release`. Ninja is provided by `depot_tools` so make sure you set up your `PATH` correctly.
Once the build completes, the `out/Debug` or `out/Release` directories will contain the .so or .dylib libraries and test binaries.
## 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_.
 2. Configure your build environment to have access to `libEGL.lib` and `libGLESv2.lib` found in the build output directory (see [Building ANGLE](DevSteup.md#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](DevSetup.md#Building-ANGLE)) 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 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.
### Getting the source
The translator code is fully independent of the rest of ANGLE code and resides in `src/compiler`.  It is cross-platform and build files for operating systems other than Windows can be generated by following the `Generating project files` steps above.
### 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.