Each Windowless*Application has now a companion Windowless*Context that
manages just the GL context creation and nothing else, with the ability
to just create the context and not make it current, so it doesn't affect
current thread state and can be moved to another thread and make current
there.
Other things that were done:
* Using `NoCreateT` instead of `nullptr` for creating the application
without creating GL context.
* Properly handling failed creation of Magnum context instance -- if it
errors out, also the GL context is destroyed to make it possible to
create the context with a different configuration.
* Reworked AMD and NVidia binary driver workaround, where core context
created with specific version doesn't automatically choose the newest
available (creating compatibility context on the other hand causes
the version to get stuck on 2.1 on Mesa and OSX).
* Added the above workaround also for WindowlessWglApplication to avoid
driver issues in the future.
* Reworked WindowlessWglApplication to not be so crazily entangled. It
was a misunderstanding on my side about how WINAPI works. Much
simpler now (and I hope still working :D).
What this changes:
* Before, a Version::GLES310 shader was created with `#version 450`
directive, which is wrong, because an implementation might support
GLES 3.1 but not GL 4.5 so this was not working and also the syntax
is a bit different so this wasn't helpful at all.
* Similarly, Context::isVersionSupported(Version::GLES310) was checking
for support of OpenGL 4.5. Now it just checks for
`ARB_ES3_1_compatibility` extension.
* Added a small isVersionES() utility that just tells whether given
version is ES or not.
Allows to break the dependency on the <Magnum/CubeMapTexture.h> header
in Framebuffer, TextureState and elsewhere. The old
CubeMapTexture::Coordinate enum is now just an alias, is marked as
deprecated and will be removed in a future release.
Toggles between using CGL/GLX/WGL (requiring running graphical desktop
environment) or EGL (without display attachment) for command-line
utilities and GL tests. Also exposed to the user through
MAGNUM_TARGET_HEADLESS CMake and preprocessor variables.
As with Corrade, this is not exactly backwards compatible, but for
common use case without OBJECT libraries this should not be a problem.
In any case, recreate the build dir and update your copy of all
Find*.cmake modules to avoid weird things happening.
User-facing changes:
* Documentation of all Find*.cmake modules converted to
reStructuredText to follow official CMake guidelines.
* The newfangled way to use the libraries is to link to Magnum::Shaders
instead of adding ${MAGNUM_SHADERS_INCLUDE_DIRS} to include path and
linking to ${MAGNUM_SHADERS_LIBRARIES}.
* The old ${MAGNUM_*_LIBRARIES} are deprecated and now just expand to
Magnum::* target. Use the target directly. These are also enabled
only when building with MAGNUM_BUILD_DEPRECATED.
* The old ${MAGNUM_*_INCLUDE_DIRS} are removed as the Magnum::* targets
cover these too.
Internal changes:
* Global state such as include_directories() was replaced with
target-specific settings.