This is a **preview release** — Lumiera is not usable yet.
Publication was again motivated by a series of major upgrades and clean-up.
Compilation now requires C++23 and Debian/Trixie is considered the reference
platform. The GUI is connected to the core over an asynchronous messaging
bus and the timeline display has been reshaped to accommodate flexibly
nested structures of media content, instructed by the session through
a series of _diff messages_. A scheduler has been implemented to drive
the Render Engine, but the connection to the player and UI for output
is yet unfinished.
Many versions enforced with this changeset are chosen such
as to support Ubuntu/Noble (24.04) and otherwise use versions
reasonably close to Debian-Trixie (≙reference-platform)
Since we now require a fairly modern compiler for C++23,
I have added now an explicit version check, which however
is performed only if the defined compiler is named `g++*`
Furthermore, I combed through all of our build tutorials and documentation pages
and updated a lot of information regarding dependencies and build practices...
Many years ago, I integrated the IconSvgRenderer (written by Joel Holdsworth)
directly into the SCons build by means of a custom builder with an ''emitter function''.
The build as such works fine and automatically determines which icons can be
generated from a given SVG source. However, those SVG icons tend to be rebuilt
very frequently, even while none of the SVG sources has changed.
Basically this was more of an annoyance, since we have now about 15 icons
and the rendering is really fast ... it is just ugly, especially on
incremental builds (and it could become a problem once we have a
massive amount of graphics to process.
So I took the opportunity to take close look now, since I am doing
uninspiring clean-up work since several weeks now. But that problem
turned out to be quite insidious and hard to spot.
First, AI set me off into a completely wrong angle, since it is ''not''
caused by a missing string representation of the custom Action class.
However, from there I went to watching the target checks with the debugger,
and this eventually got me to realise, that SCons mistakenly detects
a change in the Executor / the Action class.
The root cause is, that we invoke Python code from an external Module,
IconSvgRenderer.py, and this is »materialised« by SCons automatically
into a string representation, which includes memory addresses of functions
in that module. And that yields a signature, that is, quite obviously,
not stable, even while you end up sometimes with loading the code to
the same memory location.
As a solution / workaround, we now subclass the standard implementation
from SCons and override the signature function; instead of fingerprinting
the binary code, we just compute a MD5 over the python source file,
which can be easily achieved with the help of the File-Node from SCons.
Essential resources:
https://scons.org/doc/4.8.0/HTML/scons-user.html#chap-builders-writing
...and the Reference / Manpage of SCons
https://scons.org/doc/4.8.0/HTML/scons-man.html#action_objects
SCons/Action.py
SCons/Node/__init__.py
* Simplify some constructs from the Python-3 migration
* update copyright, since I did maintain the SCons build continuosly
* remove unused method from Buildhelper
Furthermore, the documentation page for our build system
https://lumiera.org/documentation/technical/build/SCons.html
has been reworked, to add a synopsis, some further background
information about the internal structure of SCons and about
the specific conventions and definitions used for Lumiera
...funny enough I never noticed this obvious mistake,
since I never install software directly into my system,
while the DEB-build does not use absolute paths...
Solution:
* SCons has this speical convention that a path prefixed with '#'
is resolved relative to the root of the build (where the SConstruct resides)
* now we apply this automatically to the two relevant settings
** INSTALLDIR
** TARGDIR
* but only (conditionally) if the configured path is relative, not absolute
As a consequence, most other hard-coded usages of the '#'-prefix can then be dropped
Debian-Docbase allows to register some HTML documentation;
My old package definition added placeholder config, which renders
the documentation configuration invalid (as pointed out by Lintian).
However, I still think it is a good idea to have the anchor point
already defined, and thus I came up with the idea of in fact
providing some usable placeholder content...
As it turns out, we also have a placeholder page at the Lumiera website,
where the User Manual is assumed to be located later — so why not extend
this one and then provide the HTML-rendering for the DEB package?
To allow for this setup
* I have now extended the placeholder page for the Website
to include some generic description about Lumiera (from the 'about' page)
* Furthermore, I added the screenshot (from the »Outer Space« page)
* and I use this a an opportunity to document the various test / demo
facilities currently available in the GUI, since these are rather obscure.
While only intended for the developer, it seems still worthwhile
to describe the possible effects — it may well be that we retain
some of that test/demo functionality and in that case, we have
now already some starting point for a documentation
* Then, to include that page as stand-alone HTML, I used the 'Print Edit WE'-plugin
from Firefox, to encode the images as inline-base64 URLs (which are restored
by a tiny JavaScript embedded into that page)
* and last but not least, our SCons buildsystem needs the ability
to install such a documentation file, since it seems most adequate
to handle this requirement as part of the generic installation (and
not hidden in some Debian scripting)
Yes, I know...
Programmers absolutely LOVE to sneak-in various nifty toggles via environment.
Yet this is an anti-pattern!
And, by extension of that verdict, a "build interface" which relies
on the implicit convention that some magical variables are set,
is **not a proper interface** but a hack.
Thus we abandon that bad practice and handle the build in a clean and explicit way.
* the DEB-Build in `debian/rules` now invokes SCons explicitly, passing arguments
* the Lumiera Build-System is FSH aware and knows the proper installation locations
* the setup of the application uses a setup configuration, shipped with the package
* there is no need to ''compile-in any configuration''
** `LUMIERA_PLUGIN_PATH` is obsolete and unused since several years now
** `LUMIERA_CONFIG_PATH` was never used at all
** consequently, we also do not need `PKGLIBDIR` and `PKGDATADIR`
A long-standing unnecessary mutual dependency caused rebuild
of most tests in the standard target, because the ''valgrind suppression''
executable was classified as »tool«, while also depending on the libraies
with the test code.
Starting with ''preview release'' `v0.pre.04`, branch and version tags
will be handled in accordance to the **Git-flow** naming scheme.
Notably this implies that from now on the version in-tree will indicate
the ''next expected release,'' adorned by a suffix to mark the preview.
To accommodate this transition to Git-flow
- the new branch `integration` will be introduced
- the version number will once (and the last time for this release)
be adjusted ''before'' forking the release branch
- branch `master` will transition to reflect the latest released state
- several existing branches will be discontinued, notably
`gui`, `steam`, `vault`, `release`, `play`
The Lumiera »Reference Platform« is now upgraded to Debian/Buster, which provides GCC-14 and Clang-20.
Thus the compiler support for C++20 language features seems solid enough, and C++23,
while still in ''experimental stage'' can be seen as a complement and addendum.
This changeset
* upgrades the compile switches for the build system
* provides all the necessary adjustments to keep the code base compilable
Notable changes:
* λ-capture by value now requires explicit qualification how to handle `this`
* comparison operators are now handled transparently by the core language,
largely obsoleting boost::operators. This change incurs several changes
to implicit handling rules and causes lots of ambiguities — which typically
pinpoint some long standing design issues, especially related to MObjects
and the ''time entities''. Most tweaks done here can be ''considered preliminary''
* unfortunately the upgraded standard ''fails'' to handle **tuple-like** entities
in a satisfactory way — rather an ''exposition-only'' concept is introduced,
which applies solely to some containers from the STL, thereby breaking some
very crucial code in the render entities, which was built upon the notion of
''tuple-like'' entities and the ''tuple protocol''. The solution is to
abandon the STL in this respect and **provide an alternative implementation**
of the `apply` function and related elements.
The build system Scons switched from using Python 2.7 to using
Python 3.x, so the build breaks on, for example, Debian Bullseye.
As a first step use `ato3` to convert Python scripts from 2 to 3.
* Lumiera source code always was copyrighted by individual contributors
* there is no entity "Lumiera.org" which holds any copyrights
* Lumiera source code is provided under the GPL Version 2+
== Explanations ==
Lumiera as a whole is distributed under Copyleft, GNU General Public License Version 2 or above.
For this to become legally effective, the ''File COPYING in the root directory is sufficient.''
The licensing header in each file is not strictly necessary, yet considered good practice;
attaching a licence notice increases the likeliness that this information is retained
in case someone extracts individual code files. However, it is not by the presence of some
text, that legally binding licensing terms become effective; rather the fact matters that a
given piece of code was provably copyrighted and published under a license. Even reformatting
the code, renaming some variables or deleting parts of the code will not alter this legal
situation, but rather creates a derivative work, which is likewise covered by the GPL!
The most relevant information in the file header is the notice regarding the
time of the first individual copyright claim. By virtue of this initial copyright,
the first author is entitled to choose the terms of licensing. All further
modifications are permitted and covered by the License. The specific wording
or format of the copyright header is not legally relevant, as long as the
intention to publish under the GPL remains clear. The extended wording was
based on a recommendation by the FSF. It can be shortened, because the full terms
of the license are provided alongside the distribution, in the file COPYING.
the new structure causes them now to be installed into $TARGET/stage
which is simply not what I want. I still consider $TARGET/gui the better choice,
since an administrator or packager is not aware of our layer namings.
The existing solution was half baked anyway, it did not really replicate the source tree.
On the other hand, I want to retain the location of the CSS files within the GUI tree,
since I consider it a good practice, to keep "code-like" resources with the actual code,
and not far away in some arcane "data" directory.
No I've noticed, that the env.GuiResource() function is only used once, for this very task.
So, for the time being, we can keep it simple and deditaced to that task, i.e
we pick up all CSS files we find and install it into a single target directory.
NOTE: this issue has brought to my attention two further, completely unrelated issues
* Ticket #1192 (Lumiera hangs on failed GUI start)
* The ProcDispatcher does an idle wait, due to an error in timed-wait implementation
This warning is only relevant when object files compile with and without
C++17 language level are to be linked into a single executable; starting
with C++17, new style 'noexcept' specifications will become part of the
function signature and thus part of the mangled function name. Linkiing
mixed object files might fail in such a situation.
Obviously this warning is not relevant for us; moreover we plan to
upgrade to C++17 soon
...this is proposed by debian; lets see how this turns out
We could also add -fstack-protector-strong, but I prefer
to set this in the package definition
...this will be the third preview release
Lumiera is still in pre-alpha stage, and thus
there are no proper releases, just preview snapshots.
Again this version will be built and packaged
on several supported Linux platforms
This means we have rather tight compiler requirements now.
Beyond that, we expect no serious impact; the most notable
C++14 feature we're likely to use soon is type inference
on lambda arguments.
Why GNU extensions? They where on by default previously,
so we're changing nothing besides the C++ standard level.
AFAIK, we're using a GNU extension at one place, and this
could be replaced by 'decltype' now.
The recommendation is to use the link flag --no-undefined
and to fed *all* dependencies to the respective link step.
This changeset enables this strict linking of dependencies.
It turned out that our dependencies were already sane
(with the sole exception of a direct dependency to X-Lib
in the XV viewer widget)
...this will be the second preview release
Lumiera is still in pre-alpha stage, and thus there
are no proper releases, just preview snapshots
from time to time.
But we're providing Debian packages allready
Note: this drops some backwards compatibility. We're targeting now
roughly the range between Ubuntu-Precise (LTS) and Debian/testing,
with Debian/stable as the reference system.
The naming scheme for Boost-Libraries was adjusted with Boost-1.42
for Unix-Platforms. Now the '-mt' suffix isn't included any more, but
the libraries available through the usual packaging mechanisms can be
assumed to be thread safe.
See also http://issues.lumiera.org/ticket/759
