Consider moving to CMake

[szhorvat]

Is your feature request related to a problem? Please describe.

XaoS has moved to Qt 6. The standard build system from Qt 6 is CMake, not qmake. Some package systems, such as MacPorts, do not have good support for qmake with Qt 6. Packaging XaoS 4.3+ would be much easier if it used CMake.

Describe the solution you'd like

Transition to a CMake-based build system.

Describe alternatives you've considered

To continue using qmake is troublesome and time consuming to set up with some package managers, such as MacPorts.

Additional context
—

[kovzol]

That's a good idea, please contribute code if you have some details in mind. Thanks!

[kovzol]

Please have a look at https://github.com/xaos-project/XaoS/blob/master/CMakeLists.txt -- it may work on Mac automatically. Thanks to Werner Volken for the first version of this configuration file.

[szhorvat]

I'm getting:

/Users/szhorvat/Repos/XaoS/src/include/config.h:36:9: error: __float128 is not supported on this target

But I did not look into it in detail.

[kovzol]

Yes, I'm fighting with the same issue. Thanks for the feedback.
It is because, seemingly, clang is used for compilation, and not gcc.

[szhorvat]

I didn't look in the CMake file, but it seems that gcc / g++ are being forced. This shouldn't be done. Leave it to CMake to choose the compiler (which will then allow the user to use alternative compilers). On macOS, the gcc command is an alias for Clang. I do have GCC installed under a different name, but I cannot use it because the build system does not respec tthe compiler choice.

[szhorvat]

So this is wrong:

# use gcc also Mac because Apple clang lacks quadmath support
set(CMAKE_C_COMPILER gcc)
set(CMAKE_CXX_COMPILER g++)

Apple does not distribute GCC. There is no way to force GCC on macOS. GCC can only be installed from other sources (MacPorts, Homebrew and the like).

[szhorvat]

I can get around this by removing the above-mentioned two lines, but then I run into other issues which may not be related to XaoS. I'm getting this when using GCC 13 installed with MacPorts:

In file included from /opt/local/libexec/qt6/lib/QtCore.framework/Headers/qglobal.h:98,
                 from /opt/local/libexec/qt6/lib/QtCore.framework/Headers/QtCore:4,
                 from /opt/local/libexec/qt6/lib/QtWidgets.framework/Headers/QtWidgetsDepends:3,
                 from /opt/local/libexec/qt6/lib/QtWidgets.framework/Headers/QtWidgets:3,
                 from /Users/szhorvat/Repos/XaoS/src/ui/customdialog.cpp:1:
/opt/local/libexec/qt6/lib/QtGui.framework/Headers/qopenglcontext_platform.h:49:39: error: '#pragma' is not allowed here
   49 |     static QOpenGLContext *fromNative(QT_IGNORE_DEPRECATIONS(NSOpenGLContext) *context, QOpenGLContext *shareContext = nullptr);
      |                                       ^~~~~~~~~~~~~~~~~~~~~~

As you can see the complaint is about Qt code, not XaoS code.

[kovzol]

I try to force it like this (on GitHub Actions):
mkdir cbuild; cd cbuild; cmake -DCMAKE_C_COMPILER=gcc-13 -DCMAKE_CXX_COMPILER=g++-13 ..
And it seems to be recognized correctly:

-- The C compiler identification is GNU 13.2.0
-- The CXX compiler identification is GNU 13.2.0

But still I get the error with the __float128 issue. Is it possible that clang is forced somewhere?

[kovzol]

The current version compiles on both Linux and Mac. On Linux it is possible to start cmake with the -DDEEPZOOM=ON option. I think, something like adding -DCMAKE_C_COMPILER=gcc-13.2 -DCMAKE_CXX_COMPILER=g++-13.2 -DDEEPZOOM=ON could do the trick also on Mac, but I am afraid that this will not work on GitHub Actions for some reason.

[szhorvat]

When I try to build with CMake on macOS, I get the following warning:

CMake Warning at /opt/local/libexec/qt6/lib/cmake/Qt6/FindWrapOpenGL.cmake:41 (target_link_libraries):
  Target "XaoS" requests linking to directory
  "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.5.sdk/System/Library/Frameworks".
  Targets may link only to libraries.  CMake is dropping the item.
Call Stack (most recent call first):
  /opt/local/share/cmake-3.29/Modules/CMakeFindDependencyMacro.cmake:76 (find_package)
  /opt/local/libexec/qt6/lib/cmake/Qt6/QtPublicDependencyHelpers.cmake:33 (find_dependency)
  /opt/local/libexec/qt6/lib/cmake/Qt6Gui/Qt6GuiDependencies.cmake:30 (_qt_internal_find_third_party_dependencies)
  /opt/local/libexec/qt6/lib/cmake/Qt6Gui/Qt6GuiConfig.cmake:40 (include)
  /opt/local/share/cmake-3.29/Modules/CMakeFindDependencyMacro.cmake:76 (find_package)
  /opt/local/libexec/qt6/lib/cmake/Qt6/QtPublicDependencyHelpers.cmake:108 (find_dependency)
  /opt/local/libexec/qt6/lib/cmake/Qt6Widgets/Qt6WidgetsDependencies.cmake:39 (_qt_internal_find_qt_dependencies)
  /opt/local/libexec/qt6/lib/cmake/Qt6Widgets/Qt6WidgetsConfig.cmake:40 (include)
  /opt/local/libexec/qt6/lib/cmake/Qt6/Qt6Config.cmake:157 (find_package)
  CMakeLists.txt:114 (find_package)

The build does succeed though, and the app runs.