Disorder

h1. Installation

h2. Obtaining the Source Code

h3. Release Tarballs

Disorder doesn't have any official releases yet.  If/when that happens, release source tarballs will be available on the "Files":http://oss.squalllinesoftware.com/projects/disorder/files page.  This is what you want if you are looking for stability and something ready for production use.  You'll probably want to use the most recent version found on that page.

h3. SCM

The Disorder source code is hosted in a "Mercurial":https://www.mercurial-scm.org repository.  This is what you want if you are looking for the very latest bleeding edge of the code for contributing to Disorder, forking an evil fork, or whatever other reason you may have.

Read the "Mercurial Documentation":http://hgbook.red-bean.com/ if you aren't familiar with that and you want to go this route.

To clone the repository including the full history:

<pre>hg clone http://hg.squalllinesoftware.com/oss/disorder</pre>

h2. Prerequisites

Given the assumption that a somewhat sane build environment for C++ already exists on the build machine, the following third party things are required to build Disorder:

* "ASIO":http://think-async.com >= 1.12.1

** Either the standalone version of ASIO or the one built into boost can be used.

* "Eigen":http://eigen.tuxfamily.org >= 3.0.5

* "Google Test/Mock":https://github.com/google/googletest >= 1.7.0

* At least one of the following geospatial conversion libraries:

** "GeographicLib":https://geographiclib.sourceforge.io >= 1.45

** C++ version of the "SEDRIS SRM":http://www.sedris.org/srm_4.4/srm_c_cpp.htm >= 4.4.0

** Patches to support other geospatial conversion libraries are welcome

* A "Python 3":http://www.python.org interpreter (needed to use the "meson":https://mesonbuild.com/ build system)

* The ninja build system

* A C++ compiler capable of understanding the "ISO C++ 2011 Standard":http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=50372

** "GCC":http://gcc.gnu.org >= 4.7.0

** "Clang++":http://clang.llvm.org >= 3.1.0

** Visual Studio >= 2013 (version 12.x)

*** If you intend to use Visual Studio to build this thing on Windows, you're going to need at least 2013.

*** You can, of course, also use gcc or clang to build disorder on windows in a "cygwin":http://cygwin.org/ environment.

Build and install these things in accordance with the instructions for your operating system provided by each vendor.  Some hints for certain platforms follow.

h3. Debian Linux and Derivatives

If you don't already have meson, get it and its dependencies (python 3 and ninja):

<pre>sudo apt-get install meson</pre>

That's it.  You can optionally install the Disorder build dependencies from the package manager.  If the dependencies aren't installed on the system, Disorder will automatically download their source code and build them with the library.

If you'd rather install them on your system:

<pre>sudo apt-get install libasio-dev libeigen3-dev libgeographic-dev googletest google-mock</pre>

This may install older packages than the ones that Disorder is known to work with.  That may not work out so awesome.  Consider yourself warned.

h2. Options

There are various options available to control things.  If you don't know what you want, you can skip this section as disorder will try to do something sane.  Don't worry, you can change options later and rebuild if you decide you really want something different than the default.

To get a list of available options:

<pre>meson configure</pre>

Here are some useful options:

|_. Option |_. Argument |_. Description |

| cpp_std | c++11, c++14, c++17 | select the desired C++ standard (default: c++11) |

| default_library | shared, static, both | select the type of library to make (default: shared on Linux, static on Windows) |

| buildtype | plain, debug, debugoptimized, release, minsize, custom | type of build to produce (default: debug) |

| wrap_mode | default, nofallback, nodownload, forcefallback | controls how dependencies are found see "Meson FAQ":https://mesonbuild.com/FAQ.html#does-wrap-download-sources-behind-my-back for more details (default: default) |

Options are applied as arguments to meson setup when running the configuration step described below.  The options are specified as @--D<option>=<value>@ where <option> is the option to set and <value> is the value to set it to.  For example, to use the C++14 standard, supply @--Dcpp_std=c++14@ to meson.

h2. Configuration

If everything is setup properly, this step will be a breeze, but it is important to resolve any errors produced by the configuration step prior to attempting to compile Disorder.

h3. General

The basic idea of configuration is to allow disorder to learn enough about your build platform to be able to compile.  Disorder uses the "meson":https://mesonbuild.com build system to configure and generate a "ninja":https://ninja-build.org recipe for compilation.

On Windows, meson will download all the dependencies, build, and utilize them out of the @subprojects@ subdirectory.

On linux-like systems, meson will attempt to find dependencies installed in the general system location falling back to downloading them and using them out of the @subprojects@ subdirectory.

If you don't want the default behavior on your platform, you can override it using options.  The options for configuring disorder's dependencies can be found via @meson configure@.

Some of said options are thusly enumerated for your convenience:

h4. ASIO

|_. Option |_. Argument |_. Description |

| asio | default, standalone, boost | Select the preferred version of the ASIO library.  The default option prefers the standalone version with a fallback to boost if the standalone version is not found. (default: default) |

| asio_root | path to the root of the standalone ASIO library (eg. /opt/asio-1.12.2) | Tells disorder where to find the standalone ASIO library. |

h4. Eigen

|_. Option |_. Argument |_. Description |

| eigen_root | path to the root of the Eigen library (eg. /opt/eigen-3.1.2) | Tells disorder where to find the Eigen library. |

h4. SEDRIS SRM

By default Disorder will use the "GeographicLib":https://geographiclib.sourceforge.io library.  If that's what you want, no extra setup is necessary.

If you want to use the SEDRIS SRM, there's a little more work to do.  Because the SEDRIS SRM creators don't give away their source code without forcing people to have an account in their system and agree to their license, Disorder is not distributed with the SEDRIS SRM and cannot automatically download it for you.

The following additional steps are required to use the SEDRIS SRM:

* Download the "SEDRIS SRM":http://www.sedris.org/srm_4.4/srm_c_cpp.htm source code .tgz file.  *NOTE*: Always pick the Unix version even on Windows.  They are the same except for the compression format.

* Put the srm_c_cpp_sdk_4.4.tgz file in a subdirectory off the root of the disorder source tree called subprojects/packagecache

* Use @--enabled_geospatial_libraries=sedris_srm@ option when configuring disorder

** @--enabled_geospatial_libraries=sedris_srm,geographic_lib@ can be used to include support for both libraries allowing run-time selection of the one that gets used

*** If both libraries are enabled and you want to use SEDIRS_SRM by default instead of GeographicLib, also apply the @--preferred_geospatial_library=sedris_srm@ option

h3. Creating a Build Directory and Configuring Disorder

Once you've decided on the options, make a <build_dir> directory and configure disorder where <options> should be replaced with the desired options:

<pre>meson <build_dir> <options></pre>

For example to use the C++17 standard and a <build_dir> called "build-c++17":

<pre>meson build-c++17 --Dcpp_std=c++17</pre>

If you see an error message from that step, it must be fixed in order to proceed.

h3. Linux

h4. Clang++

To use the "Clang":http://clang.llvm.org/ C++ compiler instead of "GCC":http://gcc.gnu.org/, assuming clang++ is installed on the build system:

<pre>CXX=<put the path to clang++ here> meson <build_dir> <options></pre>

For example, to make a release build using C++14 with a build directory of build-clang-c++14-release:

<pre>CXX=clang++ meson build-clang-c++14-release --Dcpp_std=c++14 --Dbuildtype=release</pre>

h3. Windows

On windows, your $PATH environment variable needs to include the path to the Python interpreter.

If you're using the Visual Studio compiler, you must run the configuration and compilation steps from within the appropriate Visual Studio command prompt for the configuration you want to build for.

Also, shared libraries cannot be used on windows as Disorder does not properly export symbols.  Patches welcome.

h2. Compiling

The basic strategy for building Disorder is to invoke the ninja build system from within the build directory produced by the configuration step.

This is generally all it takes:

<pre>cd build

ninja</pre>

h2. Ensuring Build Correctness

Due to the complexity of varied compilers and build configurations, it is imperative that you preform the necessary testing on your build to ensure that it performs correctly.

Don't fret.  It's easy and is well worth the time it takes for the peace of mind you gain.  Just tell ninja to run the unit test from inside your build directory like this:

<pre>ninja test</pre>

That should result in something like this:

<pre>

[0/1] Running all tests.

1/1 disorder unit test                      OK       0.42 s

Ok:                    1

Expected Fail:         0

Fail:                  0

Unexpected Pass:       0

Skipped:               0

Timeout:               0

Full log written to /usr/local/src/disorder/build/meson-logs/testlog.txt

</pre>

Ninja thinks there is only one test, but it ran the full test suite which contains thousands of tests.  Yes, it can do them all in less than a second depending on your hardware.  If you see something besides "OK" on line 2 and "Ok: 1" on line 4, things are not okay.  Look at the full log specified on the last output line to see exactly what went wrong.

If it's unhappy, please file a bug report and/or fix it yourself and send in a patch.  Under no circumstances should you attempt to use a build that fails the test suite.  A test failure means disorder isn't working as expected for some reason and that reason needs to be resolved for your simulation to function properly.  Disorder does not have any known flaky unit tests.  If a test doesn't work, something is broken.

h2. Building Against the Disorder Library

h3. Installing Disorder

Disorder can be installed somewhere on your system to make a neat little package out of all the things you'll need to build something against the library.  To do that, issue the @ninja install@ command from inside your build directory.  If you want to control where that sticks stuff, add @DESTDIR=<dest_dir>@ to the front that where <dest_dir> is where you want to install it.  For example, to install disorder under /opt:

<pre>DESTDIR=/opt ninja install</pre>

h3. Compiling Your Project Against Disorder

In order to compile your goodness against the Disorder library, you'll need to have the installed header files in your compiler's include path.  The geospatial libraries aren't exposed so you don't need those in your include path.

h3. Linking Your Project With Disorder

Just link your program against Disorder's library that can be found in the @<build>/src/disorder@ directory.  If you've installed Disorder using ninja, the library will be in the appropriate location under the installation root path.