Building Lumiera from source
============================
:Date: 2020
:toc:

At the moment you can build Lumiera, start the standard Lumiera GUI and run the
Lumiera test suite. The GUI you start might look like a mockup, but in fact is
_is_ the real application; just there isn't much wiring between GUI, model and
core yet. This will remain the state of affairs for the foreseeable future, since
we're developing core components against a test suite with unit and integration
tests. Thus, the growth of our test suite is the only visible indication of
progress.

This tutorial outlines the fundamental steps required to compile Lumiera on
Linux (or a comparable) system. We'll assume that you have a certain familiarity
with _commandline survival skills_ on your system. To help you getting started,
this tutorial lists all the necessary commands explicitly. footnote:[there are
some minor differences between the various Debian based distributions, thus the
exact version numbers and package names appearing in our example commands might
be slightly different on your system]

There are two distinct methods to build:

- use the Debian source code package of Lumiera (the »Debian way«)
- use Git to retrieve all source code and build the »classical way«


NOTE: just compiling Lumiera on a _Debian-based_ system (e.g. Mint, Ubuntu...)
      is much simpler when using the Debian source package. See the separate
      link:DebianBuilding.html[tutorial page] for this footnote:[besides, there
      is a separate page with general
      link:/debian/[instructions for installing on Debian/Ubuntu]).]
      The purpose of this tutorial here is to show you the elementary
      and generic steps to compile Lumiera from source.


Requirements
------------

To build Lumiera, you'll need a _build environment_ together with the
_development packages_ of the libraries Lumiera depends on.
footnote:[there is a separate documentation page listing the
link:{ldoc}/technical/build/BuildDependencies.html[build dependencies] explicitly.
We'll try to keep that information up to date -- but in the end, the really
authoritative information about the build dependencies is encoded into the
link:{ldoc}/technical/build/SCons.html[build system]. Thus, when the build
system aborts, indicating that a never version of some library is required,
then usually the build system is right...]
More specifically, you'll need the GNU C/C\++ compiler with C++17 support (Version >= 7)
in addition to the following tools and libraries:

 * link:http://git-scm.com/[Git] (version management system)
 * link:http://www.scons.org/[SCons build system]
 * link:http://www.boost.org/[Boost libraries]
 * link:http://gmerlin.sourceforge.net/[GAVL library]
 * link:http://nobug.pipapo.org/[NoBug] (see below)
 * Lumiera source code 

The GUI depends on the following:

 * link:http://www.gtkmm.org/en/[gtkmm]
 * link:http://cgit.freedesktop.org/xorg/lib/libXv[libXv]
 * link:https://wiki.gnome.org/LibRsvg[lib rSVG]
 * link:https://git.gnome.org/browse/gdl[lib GDL]

TIP: Generally speaking, when you want to build software, you'll need the
_development_ version of the packages that contain the headers and pre-built
libraries to link against. These packages are usually named `-devel` or `-dev`.

For Debian based systems, e.g. Mint, Ubuntu..., you can install these packages as follows:

-------------------------------------------------------------------------------------
sudo apt-get install build-essential scons git-core valgrind intltool \
libboost-dev libboost-program-options-dev libboost-regex-dev libboost-filesystem-dev \
libgavl-dev libgtkmm-3.0-dev libgdl-3-dev librsvg2-dev libxv-dev
-------------------------------------------------------------------------------------



Build Directory
---------------

You'll need to check out the source code in some directory or other. You'll also
have to use this directory to build Lumiera. This could be a temporary
directory, or some "workspace" directory below your home directory. We'll refer
to this directory as _workspace directory_ . 


Lumiera Specific Libraries
--------------------------
Now that you have your basic build environment prepared, the next step is to care
for some special libraries required by Lumiera that are not directly part of the
Lumiera project itself, but aren't readily available through the usual package
manager of the common distributions either. footnote:[we maintain our own Debian
package depot at Lumiera.org and provide binary Debian packages for a range of
distributions; yet this tutorial strives at showing the basic and generic method
for building. Thus we'll show you here how to build these libraries from source
yourself] Thus, we'll have to get the source code for these support libraries,
build and install them before we're able to compile Lumiera.

WARNING: Note that the following procedures will try to install files into your
base system below `/usr/local`. +
To do so, you'll need administrative permission for the machine you're working
on. These additions might interfere with other libraries installed by your
package manager (if you get into trouble updating your system later on,
you might have to manually remove these libraries).


NoBug: building and installing
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

link:http://nobug.pipapo.org/[NoBug] is an instrumentation and diagnostics library. +
Enter _workspace direcory_ as explained above. 
Get the NoBug source code:

------------------------------------------------------------
git clone git://git.lumiera.org/debian/nobug
------------------------------------------------------------

This will create a (sub)directory called nobug that contains source code. +
Compile and install NoBug with the following commands:
------------------------------------------------------------
cd nobug
autoreconf -i
mkdir build
cd build
../configure
make
sudo make install
------------------------------------------------------------

GDL-mm: building and installing
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The *GNOME Docking library* is available through your your package manager,
but we additionally need the C++ bindings. Since these haven't made it into the
standard repositories yet, we provide a suitable custom package here;
the following shows how to build the latter

Version limitation::
  we rely on GTK-3 and thus need a compatible GDL-3.

There is a dependency on `xmlto`, which is an xml converter. To install on Debian: 

------------------------------------------------------------
apt-get install xmlto
------------------------------------------------------------

------------------------------------------------------------
git clone git://git.lumiera.org/debian/gdlmm
cd gdlmm
git checkout debian
./configure
make
sudo make install
------------------------------------------------------------



verify library linkage
~~~~~~~~~~~~~~~~~~~~~~

The compile might warn you to add various directories to `/etc/ld.so.conf` and then
to run `ldconfig`. This will allow your dynamic linker to pick up the newly built
libraries later when you try to start Lumiera.  If you don't want to reconfigure
your system and add `/usr/local/lib` to the linker configuration, you may
alternatively just add the directories to your `LD_LIBRARY_PATH` environment
variable.

Either way, check that all libraries are accessible and OK:

------------------------------------------------------------
sudo ldconfig -v | grep 'nobug'
------------------------------------------------------------

and you should get a list of the libraries, part of which should look like this:

------------------------------------------------------------
        libnobug.so.0 -> /usr/local/lib/libnobug.so.0.0.0
        libnobugmt.so.0 -> /usr/local/lib/libnobugmt.so.0.0.0
        libgdl-lum.so.0 -> /usr/local/lib/libgdl-lum.so.0.0.0
------------------------------------------------------------

or similar. The same applies to other custom libraries you needed to build
explicitly for your system. If any of these libraries are not listed, you'll
have to see why before you can continue.


Building Lumiera
----------------

Next, after having built and installed the external libraries, go into the
_workspace directory_ and retrieve the Lumiera source code. Thereafter, build
Lumiera by invoking the *scons* build
footnote:[more options for building with scons can be found via: `scons -h` ]
-----------------
git clone git://git.lumiera.org/LUMIERA
cd LUMIERA
scons
-----------------

maybe build and run the test suite by issuing `scons check`

The build process will take some time, so sit back and relax.

NOTE: you do not need to _install_ Lumiera. It will find all files it requires
relative to the directory structure it generates, which is freely relocatable
as a whole. Just invoke the +target/lumiera+ executable. The current
working directory is not particularly relevant.

After the build has finished successfully, you should be able to start Lumiera.
Currently, this will bring up the GUI, _without any further functionality_ (!)

You should see something like this:

image:{l}/images/lumiera_gui_small.png[Current Lumiera GUI Screenshot]


What's next?
------------
If you're a coder, maybe you have found something to improve...? +
Contributing to Lumiera is easy, thanks to *Git*

-> Tutorial link:contributing.html[Contributing to Lumiera coding]

