/*!

@page compile Compiling GLFW

@tableofcontents

This is about compiling the GLFW library itself.  For information on how to
build applications that use GLFW, see the @ref build guide.


@section compile_cmake Using CMake

GLFW uses [CMake](http://www.cmake.org/) to generate project files or makefiles
for a particular development environment.  If you are on a Unix-like system such
as Linux or FreeBSD or have a package system like Fink, MacPorts, Cygwin or
Homebrew, you can simply install its CMake package.  If not, you can download
installers for Windows and OS X from the [CMake website](http://www.cmake.org/).

@note CMake only generates project files or makefiles.  It does not compile the
actual GLFW library.  To compile GLFW, first generate these files and then use
them in your chosen development environment to compile the actual GLFW library.


@subsection compile_deps Dependencies

Once you have installed CMake, make sure that all other dependencies are
available.  On some platforms, GLFW needs a few additional packages to be
installed.  See the section for your chosen platform and development environment
below.


@subsubsection compile_deps_msvc Dependencies for Visual C++ on Windows

The Microsoft Platform SDK that is installed along with Visual C++ already
contains all the necessary headers, link libraries and tools except for CMake.
Move on to @ref compile_generate.


@subsubsection compile_deps_mingw Dependencies for MinGW or MinGW-w64 on Windows

Both the MinGW and the MinGW-w64 packages already contain all the necessary
headers, link libraries and tools except for CMake.  Move on to @ref
compile_generate.


@subsubsection compile_deps_mingw_cross Dependencies for MinGW or MinGW-w64 cross-compilation

Both Cygwin and many Linux distributions have MinGW or MinGW-w64 packages.  For
example, Cygwin has the `mingw64-i686-gcc` and `mingw64-x86_64-gcc` packages
for 32- and 64-bit version of MinGW-w64, while Debian GNU/Linux and derivatives
like Ubuntu have the `mingw-w64` package for both.

GLFW has CMake toolchain files in the `CMake/` directory that allow for easy
cross-compilation of Windows binaries.  To use these files you need to add a
special parameter when generating the project files or makefiles:

@code{.sh}
cmake -DCMAKE_TOOLCHAIN_FILE=<toolchain-file> .
@endcode

The exact toolchain file to use depends on the prefix used by the MinGW or
MinGW-w64 binaries on your system.  You can usually see this in the /usr
directory.  For example, both the Debian/Ubuntu and Cygwin MinGW-w64 packages
have `/usr/x86_64-w64-mingw32` for the 64-bit compilers, so the correct
invocation would be:

@code{.sh}
cmake -DCMAKE_TOOLCHAIN_FILE=CMake/x86_64-w64-mingw32.cmake .
@endcode

For more details see the article
[CMake Cross Compiling](http://www.paraview.org/Wiki/CMake_Cross_Compiling) on
the CMake wiki.

Once you have this set up, move on to @ref compile_generate.


@subsubsection compile_deps_xcode Dependencies for Xcode on OS X

Xcode comes with all necessary tools except for CMake.  The required headers
and libraries are included in the core OS X frameworks.  Xcode can be downloaded
from the Mac App Store or from the ADC Member Center.

Once you have Xcode installed, move on to @ref compile_generate.


@subsubsection compile_deps_x11 Dependencies for Linux and X11

To compile GLFW for X11, you need to have the X11 and OpenGL header packages
installed, as well as the basic development tools like GCC and make.  For
example, on Ubuntu and other distributions based on Debian GNU/Linux, you need
to install the `xorg-dev` and `libglu1-mesa-dev` packages.  The former pulls in
all X.org header packages and the latter pulls in the Mesa OpenGL and GLU
packages.  GLFW itself doesn't need or use GLU, but some of the examples do.
Note that using header files and libraries from Mesa during compilation
_will not_ tie your binaries to the Mesa implementation of OpenGL.

Once you have installed the necessary packages, move on to @ref
compile_generate.


@subsection compile_generate Generating build files with CMake

Once you have all necessary dependencies it is time to generate the project
files or makefiles for your development environment.  CMake needs to know two
paths for this: the path to the _root_ directory of the GLFW source tree (i.e.
_not_ the `src` subdirectory) and the target path for the generated files and
compiled binaries.  If these are the same, it is called an in-tree build,
otherwise it is called an out-of-tree build.

One of several advantages of out-of-tree builds is that you can generate files
and compile for different development environments using a single source tree.

@note This section is about generating the project files or makefiles necessary
to compile the GLFW library, not about compiling the actual library.


@subsubsection compile_generate_cli Generating files with the CMake command-line tool

To make an in-tree build, enter the _root_ directory of the GLFW source tree
(i.e. _not_ the `src` subdirectory) and run CMake.  The current directory is
used as target path, while the path provided as an argument is used to find the
source tree.

@code{.sh}
cd <glfw-root-dir>
cmake .
@endcode

To make an out-of-tree build, make another directory, enter it and run CMake
with the (relative or absolute) path to the root of the source tree as an
argument.

@code{.sh}
cd <glfw-root-dir>
mkdir build
cd build
cmake ..
@endcode

Once you have generated the project files or makefiles for your chosen
development environment, move on to @ref compile_compile.


@subsubsection compile_generate_gui Generating files with the CMake GUI

If you are using the GUI version, choose the root of the GLFW source tree as
source location and the same directory or another, empty directory as the
destination for binaries.  Choose _Configure_, change any options you wish to,
_Configure_ again to let the changes take effect and then _Generate_.

Once you have generated the project files or makefiles for your chosen
development environment, move on to @ref compile_compile.


@subsection compile_compile Compiling the library

You should now have all required dependencies and the project files or makefiles
necessary to compile GLFW.  Go ahead and compile the actual GLFW library with
these files, as you would with any other project.

Once the GLFW library is compiled, you are ready to build your applications,
linking it to the GLFW library.  See the @ref build guide for more information.


@subsection compile_options CMake options

The CMake files for GLFW provide a number of options, although not all are
available on all supported platforms.  Some of these are de facto standards
among projects using CMake and so have no `GLFW_` prefix.

If you are using the GUI version of CMake, these are listed and can be changed
from there.  If you are using the command-line version, use the `ccmake` tool.
Some package systems like Ubuntu and other distributions based on Debian
GNU/Linux have this tool in a separate `cmake-curses-gui` package.


@subsubsection compile_options_shared Shared CMake options

`BUILD_SHARED_LIBS` determines whether GLFW is built as a static
library or as a DLL / shared library / dynamic library.

`LIB_SUFFIX` affects where the GLFW shared /dynamic library is installed.  If it
is empty, it is installed to `${CMAKE_INSTALL_PREFIX}/lib`.  If it is set to
`64`, it is installed to `${CMAKE_INSTALL_PREFIX}/lib64`.

`GLFW_CLIENT_LIBRARY` determines which client API library to use.  If set to
`opengl` the OpenGL library is used, if set to `glesv1` for the OpenGL ES 1.x
library is used, or if set to `glesv2` the OpenGL ES 2.0 library is used.  The
selected library and its header files must be present on the system for this to
work.

`GLFW_BUILD_EXAMPLES` determines whether the GLFW examples are built
along with the library.

`GLFW_BUILD_TESTS` determines whether the GLFW test programs are
built along with the library.

`GLFW_BUILD_DOCS` determines whether the GLFW documentation is built along with
the library.


@subsubsection compile_options_osx OS X specific CMake options

`GLFW_USE_CHDIR` determines whether `glfwInit` changes the current
directory of bundled applications to the `Contents/Resources` directory.

`GLFW_USE_MENUBAR` determines whether the first call to
`glfwCreateWindow` sets up a minimal menu bar.

`GLFW_USE_RETINA` determines whether windows will use the full resolution of
Retina displays.

`GLFW_BUILD_UNIVERSAL` determines whether to build Universal Binaries.


@subsubsection compile_options_win32 Windows specific CMake options

`USE_MSVC_RUNTIME_LIBRARY_DLL` determines whether to use the DLL version or the
static library version of the Visual C++ runtime library.  If set to `ON`, the
DLL version of the Visual C++ library is used.  It is recommended to set this to
`ON`, as this keeps the executable smaller and benefits from security and bug
fix updates of the Visual C++ runtime.

`GLFW_USE_DWM_SWAP_INTERVAL` determines whether the swap interval is set even
when DWM compositing is enabled.  If this is `ON`, the swap interval is set even
if DWM is enabled.  It is recommended to set this to `OFF`, as doing otherwise
can lead to severe jitter.

`GLFW_USE_OPTIMUS_HPG` determines whether to export the `NvOptimusEnablement`
symbol, which forces the use of the high-performance GPU on Nvidia Optimus
systems.  This symbol needs to be exported by the EXE to be detected by the
driver, so the override will not work if GLFW is built as a DLL.  See _Enabling
High Performance Graphics Rendering on Optimus Systems_ for more details.


@subsubsection compile_options_egl EGL specific CMake options

`GLFW_USE_EGL` determines whether to use EGL instead of the platform-specific
context creation API.  Note that EGL is not yet provided on all supported
platforms.


@section compile_manual Compiling GLFW manually

If you wish to compile GLFW without its CMake build environment then you will
have to do at least some of the platform detection yourself.  GLFW needs
a number of configuration macros to be defined in order to know what it's being
compiled for and has many optional, platform-specific ones for various features.

When building with CMake, the `glfw_config.h` configuration header is generated
based on the current platform and CMake options.  The GLFW CMake environment
defines `_GLFW_USE_CONFIG_H`, which causes this header to be included by
`internal.h`.  Without this macro, GLFW will expect the necessary configuration
macros to be defined on the command-line.

Three macros _must_ be defined when compiling GLFW: one selecting the window
creation API, one selecting the context creation API and one client library.
Exactly one of each kind must be defined for GLFW to compile and link.

The window creation API is used to create windows, handle input, monitors, gamma
ramps and clipboard.  The options are:

 - `_GLFW_COCOA` to use the Cocoa frameworks
 - `_GLFW_WIN32` to use the Win32 API
 - `_GLFW_X11` to use the X Window System
 - `_GLFW_WAYLAND` to use the Wayland API (experimental and incomplete)
 - `_GLFW_MIR` to use the Mir API (experimental and incomplete)

The context creation API is used to enumerate pixel formats / framebuffer
configurations and to create contexts.  The options are:

 - `_GLFW_NSGL` to use the Cocoa OpenGL framework
 - `_GLFW_WGL` to use the Win32 WGL API
 - `_GLFW_GLX` to use the X11 GLX API
 - `_GLFW_EGL` to use the EGL API

Wayland and Mir both require the EGL backend.

The client library is the one providing the OpenGL or OpenGL ES API, which is
used by GLFW to probe the created context.  This is not the same thing as the
client API, as many desktop OpenGL client libraries now expose the OpenGL ES API
through extensions.  The options are:

 - `_GLFW_USE_OPENGL` for the desktop OpenGL (opengl32.dll, libGL.so or
   OpenGL.framework)
 - `_GLFW_USE_GLESV1` for OpenGL ES 1.x (experimental)
 - `_GLFW_USE_GLESV2` for OpenGL ES 2.x (experimental)

Note that `_GLFW_USE_GLESV1` and `_GLFW_USE_GLESV2` may only be used with EGL,
as the other context creation APIs do not interface with OpenGL ES client
libraries.

If you are building GLFW as a shared library / dynamic library / DLL then you
must also define `_GLFW_BUILD_DLL`.  Otherwise, you may not define it.

If you are using the X11 window creation API then you _must_ also select an entry
point retrieval mechanism.

 - `_GLFW_HAS_GLXGETPROCADDRESS` to use `glXGetProcAddress` (recommended)
 - `_GLFW_HAS_GLXGETPROCADDRESSARB` to use `glXGetProcAddressARB` (legacy)
 - `_GLFW_HAS_GLXGETPROCADDRESSEXT` to use `glXGetProcAddressEXT` (legacy)
 - `_GLFW_HAS_DLOPEN` to do manual retrieval with `dlopen` (fallback)

In addition, support for the following X11 extensions can be enabled:

 - `_GLFW_HAS_XINPUT` to use XInput2 for high-resolution cursor motion
 (recommended)

If you are using the Cocoa window creation API, the following options are
available:

 - `_GLFW_USE_CHDIR` to `chdir` to the `Resources` subdirectory of the
   application bundle during @ref glfwInit (recommended)
 - `_GLFW_USE_MENUBAR` to create and populate the menu bar when the first window
   is created (recommended)
 - `_GLFW_USE_RETINA` to have windows use the full resolution of Retina displays
   (recommended)

@note None of the @ref build_macros may be defined during the compilation of
GLFW.  If you define any of these in your build files, make sure they are not
applied to the GLFW sources.

*/