Since commit v3.10.0-rc5~3^2 (FindOpenGL: Default to non-GLVND libraries
for legacy GL, 2017-11-08) users may set `OPENGL_gl_LIBRARY` to empty to
use GLVND components for the legacy GL interfaces. This is useful only
when one knows in advance that the GLVND components will be found.
Add a `OpenGL_GL_PREFERENCE` variable to specify a preference for legacy
GL or GLVND. The latter can suppress `OPENGL_gl_LIBRARY` only when the
needed GLVND components are found. If no preference is explicitly
specified, choose a default based on whether GLVND components were
requested (because this indicates the project has been updated for
CMake 3.10).
Issue: #17437
Issue: #17449
Projects using `OPENGL_LIBRARIES` or `OpenGL::GL` expect legacy GL.
Although GLVND OpenGL+GLX provides legacy GL interfaces, using those
library files may conflict with legacy GL library files used by
dependencies (or dependents) of such projects. Therefore we should
not yet use OpenGL+GLX when a legacy GL library is available.
If `OPENGL_gl_LIBRARY` is set then use it as the legacy GL library.
If it is *not* set then fall back to using GLVND OpenGL+GLX to provide
legacy GL interfaces. This will allow users to build projects using
GLVND even if they have not been ported.
Fixes: #17437
Find GLVND components if available. Add `GLX` and `EGL` options for
COMPONENTS that allow requesting these libraries explicitly. Introduce
new import targets for these windowing-system-specific libraries.
On a GLVND system, populate the legacy `OPENGL_LIBRARIES` variable and
the `OpenGL::GL` target using the `OpenGL` and `GLX` components. On
non-GLVND systems, continue to use the legacy `GL` library and simply do
not provide the GLVND components. Application code can choose to adapt
based on the availability of GLVND components as imported targets.
Create OpenGL::GL and OpenGL::GLU imported targets using the locations
found.
This feature was originally added by commit v3.1.0-rc1~420^2~2
(FindOpenGL: Provide imported targets for GL and GLU, 2014-05-31) but
had to be reverted by commit v3.1.0-rc3~10^2 (FindOpenGL: Revert support
for imported targets, 2014-12-01) due to issue #15267. Since then we
added support for `IMPORTED_LIBNAME` to interface libraries, so use it
to handle the case where we have only the library name without an
absolute path.
Inspired-by: Philipp Möller <bootsarehax@googlemail.com>
Closes: #15267
Per-source copyright/license notice headers that spell out copyright holder
names and years are hard to maintain and often out-of-date or plain wrong.
Precise contributor information is already maintained automatically by the
version control tool. Ultimately it is the receiver of a file who is
responsible for determining its licensing status, and per-source notices are
merely a convenience. Therefore it is simpler and more accurate for
each source to have a generic notice of the license name and references to
more detailed information on copyright holders and full license terms.
Our `Copyright.txt` file now contains a list of Contributors whose names
appeared source-level copyright notices. It also references version control
history for more precise information. Therefore we no longer need to spell
out the list of Contributors in each source file notice.
Replace CMake per-source copyright/license notice headers with a short
description of the license and links to `Copyright.txt` and online information
available from "https://cmake.org/licensing". The online URL also handles
cases of modules being copied out of our source into other projects, so we
can drop our notices about replacing links with full license text.
Run the `Utilities/Scripts/filter-notices.bash` script to perform the majority
of the replacements mechanically. Manually fix up shebang lines and trailing
newlines in a few files. Manually update the notices in a few files that the
script does not handle.
CMake had been setting OPENGL_glu_LIBRARY to AGL.framework, even
though AGL is not GLU. AGL is simply the GL component for the
deprecated Carbon framework. GLU is provided by OpenGL.framework.
A side effect of the old behavior was that if AGL was not found
(it is absent from OS X SDK 10.10 or later), then OPENGL_GLU_FOUND
would be incorrectly set to "NO".
Revert the feature added by commit v3.1.0-rc1~420^2~2 (FindOpenGL:
Provide imported targets for GL and GLU, 2014-05-31). Unfortunately it
does not work on Windows because the full path to each library file is
not actually known. The IMPORTED_LOCATION of an imported target must be
a full path, but OPENGL_gl_LIBRARY is just 'opengl32' on Windows because
the actual library file is in some implicit link directory that we may
know know.
More infrastructure will be needed in CMake to allow a name-only
imported library. Until that exists, we will not be able to provide
imported targets in FindOpenGL.
In commit 079e8469ab (... OpenGL always needs X11 on Unix, 2002-09-05)
the FindOpenGL module was taught to search for X11 as a dependency of
the OpenGL library. This was done without a detailed explanation, and
the dependency should not be explicitly needed because OpenGL headers
should not expose applications to X11 APIs directly.
Unfortunately the only way to know if anything legitimately depends on
this behavior (perhaps in static library cases) is to simply remove it
and wait for issues to be reported. If so, then we can add some kind of
compatibility setting for this later. Add a release note to draw
attention to this change.
Reported-by: Dainius "GreatEmerald" Masiliūnas <pastas4@gmail.com>
This was using nested if's, now it uses elseif to flatten that. It also removes
one "if" from the general "else" branch that checks for Apple, as that has it's
own branch anyway and can't be true at this point.
This solves a lots of warnings, e.g. in the FindModulesExecuteAll test. If the
installed version on the system is rather old this may even lead to bugs, e.g.
https://bugs.gentoo.org/show_bug.cgi?id=436540
Ancient versions of CMake required else(), endif(), and similar block
termination commands to have arguments matching the command starting the
block. This is no longer the preferred style.
Run the following shell code:
for c in else endif endforeach endfunction endmacro endwhile; do
echo 's/\b'"$c"'\(\s*\)(.\+)/'"$c"'\1()/'
done >convert.sed &&
git ls-files -z -- bootstrap '*.cmake' '*.cmake.in' '*CMakeLists.txt' |
egrep -z -v '^(Utilities/cm|Source/kwsys/)' |
egrep -z -v 'Tests/CMakeTests/While-Endwhile-' |
xargs -0 sed -i -f convert.sed &&
rm convert.sed
The FindPackageHandleStandardArgs module was originally created outside
of CMake. It was added for CMake 2.6.0 by commit e118a627 (add a macro
FIND_PACKAGE_HANDLE_STANDARD_ARGS..., 2007-07-18). However, it also
proliferated into a number of other projects that at the time required
only CMake 2.4 and thus could not depend on CMake to provide the module.
CMake's own find modules started using the module in commit b5f656e0
(use the new FIND_PACKAGE_HANDLE_STANDARD_ARGS in some of the FindXXX
modules..., 2007-07-18).
Then commit d358cf5c (add 2nd, more powerful mode to
find_package_handle_standard_args, 2010-07-29) added a new feature to
the interface of the module that was fully optional and backward
compatible with all existing users of the module. Later commit 5f183caa
(FindZLIB: use the FPHSA version mode, 2010-08-04) and others shortly
thereafter started using the new interface in CMake's own find modules.
This change was also backward compatible because it was only an
implementation detail within each module.
Unforutnately these changes introduced a problem for projects that still
have an old copy of FindPackageHandleStandardArgs in CMAKE_MODULE_PATH.
When any such project uses one of CMake's builtin find modules the line
include(FindPackageHandleStandardArgs)
loads the copy from the project which does not have the new interface!
Then the including find module tries to use the new interface with the
old module and fails.
Whether this breakage can be considered a backward incompatible change
in CMake is debatable. The situation is analagous to copying a standard
library header from one version of a compiler into a project and then
observing problems when the next version of the compiler reports errors
in its other headers that depend on its new version of the original
header. Nevertheless it is a change to CMake that causes problems for
projects that worked with previous versions.
This problem was discovered during the 2.8.3 release candidate cycle.
It is an instance of a more general problem with projects that provide
their own versions of CMake modules when other CMake modules depend on
them. At the time we resolved this instance of the problem with commit
b0118402 (Use absolute path to FindPackageHandleStandardArgs.cmake
everywhere, 2010-09-28) for the 2.8.3 release.
In order to address the more general problem we introduced policy
CMP0017 in commit db44848f (Prefer files from CMAKE_ROOT when including
from CMAKE_ROOT, 2010-11-17). That change was followed by commit
ce28737c (Remove usage of CMAKE_CURRENT_LIST_DIR now that we have
CMP0017, 2010-12-20) which reverted the original workaround in favor of
using the policy. However, existing project releases do not set the
policy behavior to NEW and therefore still exhibit the problem.
We introduced in commit a364daf1 (Allow users to specify defaults for
unset policies, 2011-01-03) an option for users to build existing
projects by adding -DCMAKE_POLICY_DEFAULT_CMP0017=NEW to the command
line. Unfortunately this solution still does not allow such projects to
build out of the box, and there is no good way to suggest the use of the
new option.
The only remaining solution to keep existing projects that exhibit this
problem building is to restore the change originally made in commit
b0118402 (Use absolute path to FindPackageHandleStandardArgs.cmake
everywhere, 2010-09-28). This also avoids policy CMP0017 warnings for
this particular instance of the problem the policy addresses.
This adds copyright/license notification blocks CMake's find-modules.
Many of the modules had no notices at all. Some had notices referring
to the BSD license already. This commit normalizes existing notices and
adds missing notices.
