Hi fellow wiki editors!

To help newly registered users get more familiar with the wiki (and maybe older users too) there is now a {{Welcome to the wiki}} template. Have a look at it and feel free to add it to new users discussion pages (and perhaps your own).

I have tried to keep the template short, but meaningful. /Johan G

Difference between revisions of "Building using CMake"

From FlightGear wiki
Jump to: navigation, search
m (cmake option-source order altered)
(SimGear Build Options: markup)
(Tags: Mobile edit, Mobile web edit)
 
(42 intermediate revisions by 9 users not shown)
Line 1: Line 1:
 
{{Main article|Building Flightgear}}
 
{{Main article|Building Flightgear}}
  
 +
== Also see ==
 +
Please also see [[Superbuild]].
 
== Build Environment & Dependencies ==
 
== Build Environment & Dependencies ==
  
 
===Linux / Unix ===
 
===Linux / Unix ===
 
+
{{Note|as of 12/2017, people may have to build using at least OSG 3.4 due to some compilation issues -for details, refer to [[Howto:Building FlightGear without HiDPI support]]}}
 
* Install Boost, OpenAL, ALUT, PLIB and other OpenSceneGraphDependencies (eg, libpng).
 
* Install Boost, OpenAL, ALUT, PLIB and other OpenSceneGraphDependencies (eg, libpng).
 
* [[Fedora 16 Package List]]
 
* [[Fedora 16 Package List]]
FIXME - provide a list of package names for Ubuntu
+
* [[Ubuntu 12.04 Package List and Build Hints]]
 +
* Qt5 for [[Integrated Qt5 Launcher]] (optional)
  
 
* Get the OpenSceneGraph sources, either from subversion or a zip
 
* Get the OpenSceneGraph sources, either from subversion or a zip
Line 13: Line 16:
 
* '''NOTE''': On Debian AMD64 (or not 32-bit) systems (maybe including Ubuntu) there is currently a packaging error which leads to false detection of OpenAL. Until it got repaired, you have 2 options left:
 
* '''NOTE''': On Debian AMD64 (or not 32-bit) systems (maybe including Ubuntu) there is currently a packaging error which leads to false detection of OpenAL. Until it got repaired, you have 2 options left:
 
1. Goto /usr/share/cmake-2.8/Modules/ (it is the right patch on my Debian system) and expand the search path with lib/x86_64-linux-gnu/:
 
1. Goto /usr/share/cmake-2.8/Modules/ (it is the right patch on my Debian system) and expand the search path with lib/x86_64-linux-gnu/:
<pre>sudo su # to become root
+
<syntaxhighlight lang="sh">sudo su # to become root
 
cd /usr/share/cmake-2.8/Modules/ # again, use the proper path of your system
 
cd /usr/share/cmake-2.8/Modules/ # again, use the proper path of your system
 
$EDITOR FindOpenAL.cmake
 
$EDITOR FindOpenAL.cmake
Line 21: Line 24:
 
# Save it
 
# Save it
 
# Quit your editor
 
# Quit your editor
exit # to leave root</pre>
+
exit # to leave root</syntaxhighlight>
 
2. (As I did) Set a symbolic link so cmake can find it:
 
2. (As I did) Set a symbolic link so cmake can find it:
<pre>sudo su # again, become root
+
<syntaxhighlight lang="sh">sudo su # again, become root
 
cd /usr/lib/
 
cd /usr/lib/
 
ln -s x86_64-linux-gnu/* . # ignore that error for pkconfig for now
 
ln -s x86_64-linux-gnu/* . # ignore that error for pkconfig for now
 
cd pkconfig/
 
cd pkconfig/
ln -s ../x86_64-linux-gnu/pkgconfig/* .</pre>
+
ln -s ../x86_64-linux-gnu/pkgconfig/* .</syntaxhighlight>
 
* Both steps have advantages and disadvantages, e.g. when it comes to updates, so you might need to repeat your desired path and fix your symbolic links by removing them first (!) and then re-create them. A big "thanks" to James for giving me the hints. :)
 
* Both steps have advantages and disadvantages, e.g. when it comes to updates, so you might need to repeat your desired path and fix your symbolic links by removing them first (!) and then re-create them. A big "thanks" to James for giving me the hints. :)
 
* If you have OSG/PLIB on different directories than the usual, use environmental variables OSG_DIR/PLIBDIR, e.g. addd to ~/.bashrc:
 
* If you have OSG/PLIB on different directories than the usual, use environmental variables OSG_DIR/PLIBDIR, e.g. addd to ~/.bashrc:
<pre># OSG/PLIB special directory
+
<syntaxhighlight lang="sh"># OSG/PLIB special directory
 
export OSG_DIR=/opt/my-osg-path
 
export OSG_DIR=/opt/my-osg-path
export PLIBDIR=/opt/my-plib-path</pre>
+
export PLIBDIR=/opt/my-plib-path</syntaxhighlight>
 +
 
 +
Note: In order to set the CFLAGS/CXXFLAGS variables for make/gcc, simply configure cmake and define
 +
CMAKE_C_FLAGS and CMAKE_CXX__FLAGS.
 +
For example, to enable gprof:
 +
 
 +
<syntaxhighlight lang="sh">
 +
cmake ../flightgear -DCMAKE_BUILD_TYPE=DEBUG -DCMAKE_C_FLAGS=-pg -DCMAKE_CXX_FLAGS=-pg
 +
</syntaxhighlight>
  
 
===Mac===
 
===Mac===
  
* Install Xcode (from the App Store) and MacPorts (for Boost & PLIB - or build them some other way if you prefer)
+
* Install Xcode (from the App Store)
* Grab James' ALUT framework and add it to /Library/Frameworks
+
* Install Boost from MacPorts (or directly from source)
* Get the OpenSceneGraph sources, either from subversion or a zip
+
* Install the Subversion client libraries and PLIB.  These are included in the 'Mac 3rd-party dependencies' zip file. PLIB is also available through MacPorts, and Subversion is available by default on Snow Leopard (10.6) and Lion (10.7) but NOT on Mountain Lion (10.8)
 +
* Install OpenSceneGraph.
 +
 
 +
The easiest solution is to grab the 3rd-party dependencies build from Jenkins: {{Build link|path=job/Mac-3rdparty-deps/lastSuccessfulBuild/artifact/*zip*/archive.zip}}. This will give you a 'dist' directory containing PLIB, Subversion and OpenSceneGraph correctly configured. When configured SimGear and FlightGear, simply use this dist directory as CMAKE_INSTALL_PREFIX, and all the dependencies should be found with no other steps.
 +
 
 +
{{#tag:syntaxhighlight|
 +
# make a top-level directory to contain everything
 +
mkdir FGFS
 +
cd FGFS
 +
 
 +
# move the downloaded 'dist' dir from the zip inside FGFS
 +
mv <dist dir from Jenkins> .
 +
 
 +
# clone from Git
 +
{{simgear clone}}
 +
{{flightgear clone}}
 +
 
 +
mkdir sgbuild
 +
cd sgbuild
 +
cmake ../simgear -DCMAKE_INSTALL_PREFIX=$PWD/../dist
 +
make; make install
 +
 
 +
cd ..
 +
mkdir fgbuild
 +
cd fgbuild
 +
cmake ../flightgear -DCMAKE_INSTALL_PREFIX=$PWD/../dist
 +
make; make install
 +
| lang = "sh"
 +
}}
 +
 
 +
Note this demonstrates start from a clean setup - after the initial build it's sufficient to simply 'git pull' in the clones repositories, then execute a 'make; make install' in the build directories. You can of course have multiple build directories with different configurations, as described in more detail below.
  
 
===Windows===
 
===Windows===
Line 54: Line 95:
 
/home/curt/projects/fgbuild. Change into the new directory, and run
 
/home/curt/projects/fgbuild. Change into the new directory, and run
  
    cmake ../flightgear
+
<syntaxhighlight lang="sh">
 +
cmake ../flightgear
 +
</syntaxhighlight>
  
 
To generate standard Unix Makefiles in fgbuild.
 
To generate standard Unix Makefiles in fgbuild.
Line 62: Line 105:
 
Probably you want to specify an install prefix:
 
Probably you want to specify an install prefix:
  
    cmake -DCMAKE_INSTALL_PREFIX=/usr ../flightgear
+
<syntaxhighlight lang="sh">
 +
cmake -DCMAKE_INSTALL_PREFIX=/usr ../flightgear
 +
</syntaxhighlight>
  
 
Note the install prefix is automatically searched for required libraries
 
Note the install prefix is automatically searched for required libraries
Line 71: Line 116:
 
you can specify one or more via CMAKE_PREFIX_PATH:
 
you can specify one or more via CMAKE_PREFIX_PATH:
  
    cmake -DCMAKE_PREFIX_PATH="/opt/local;/opt/fgfs" ../flightgear
+
<syntaxhighlight lang="sh">
 +
cmake -DCMAKE_PREFIX_PATH="/opt/local;/opt/fgfs" ../flightgear
 +
</syntaxhighlight>
  
 
(note the use of semi-colons to specify multiple prefix paths)
 
(note the use of semi-colons to specify multiple prefix paths)
Line 81: Line 128:
 
described above will work, but specifying an INSTALL_PREFIX or PREFIX_PATH is
 
described above will work, but specifying an INSTALL_PREFIX or PREFIX_PATH is
 
usually simpler.
 
usually simpler.
 +
 +
== Debug Builds ==
  
 
By default, we select a release build. To create a debug build, use
 
By default, we select a release build. To create a debug build, use
  
    cmake -DCMAKE_BUILD_TYPE=Debug ../flightgear
+
<syntaxhighlight lang="sh">
 +
cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo ../flightgear
 +
</syntaxhighlight>
  
(or MinSizeRel, or RelWithDbg)
+
(or MinSizeRel, or Debug)
  
Debug builds will automatically use corresponding debug builds of required
+
Debug builds will automatically use corresponding debug builds of required libraries, if they are available. For example you can install debug builds of
libraries, if they are available. For example you can install debug builds of
+
 
SimGear and OpenSceneGraph, and a debug FlightGear build will use them.
 
SimGear and OpenSceneGraph, and a debug FlightGear build will use them.
  
(Debug builds of libraries have the 'd' suffix by default - Release builds
+
(Debug builds of libraries have the 'd' suffix by default - Release builds have no additional suffix)
have no additional suffix)
+
  
Note most IDE projects (eg Xcode and Visual Studio) support building all the
+
'''Important: You should keep in mind that debug builds are usually not optimized at all. Thus, it is very likely that a debug binary will perform worse (framerate/performance-wise) than a release build. Many people have reported getting just frame rates of about 30 fps when using a debug binary!'''
build types from the same project, so you can omit the CMAKE_BUILD_TYPE option
+
when running cmake, and simply pick the build configuration as normal in the
+
IDE.
+
  
It's common to have several build directories with different build
+
Note most IDE projects (eg Xcode and Visual Studio) support building all the build types from the same project, so you can omit the CMAKE_BUILD_TYPE option when running cmake, and simply pick the build configuration as normal in the IDE.
configurations, eg
+
 
 +
== Profiling ==
 +
 
 +
You can also build with optional profiling support by using '''-DENABLE_PROFILE=ON''', for details see: [[Built-in Profiler]].
 +
 
 +
== Multiple build directories ==
 +
 
 +
It's common to have several build directories with different build configurations (see [http://www.mail-archive.com/flightgear-devel@lists.sourceforge.net/msg39400.html] for more info), eg
  
 
     /home/curt/projects/flightgear (the git clone)
 
     /home/curt/projects/flightgear (the git clone)
Line 107: Line 160:
 
     /home/curt/projects/fgrelease
 
     /home/curt/projects/fgrelease
 
     /home/curt/projects/fg-with-svn-osg
 
     /home/curt/projects/fg-with-svn-osg
 +
 +
== Optional Features ==
  
 
To set an optional feature, do
 
To set an optional feature, do
  
    cmake -DFEATURE_NAME=ON  ../flightgear
+
<syntaxhighlight lang="sh">
 +
cmake -DFEATURE_NAME=ON  ../flightgear
 +
</syntaxhighlight>
  
(or 'OFF' to disable )
+
(or 'OFF' to disable)
  
 
To see the variables that can be configured / are currently defined, you can
 
To see the variables that can be configured / are currently defined, you can
 
run one of the GUI front ends, or the following command:
 
run one of the GUI front ends, or the following command:
  
    cmake -L ../flighgear
+
<syntaxhighlight lang="sh">
 +
cmake -L ../flighgear
 +
</syntaxhighlight>
  
 
Add 'A' to see all the options (including advanced options), or 'H' to see
 
Add 'A' to see all the options (including advanced options), or 'H' to see
 
the help for each option (similar to running configure --help under autoconf):
 
the help for each option (similar to running configure --help under autoconf):
  
    cmake -LH ../flightgear
+
<syntaxhighlight lang="sh">
 +
cmake -LH ../flightgear
 +
</syntaxhighlight>
  
 
== Build Targets ==  
 
== Build Targets ==  
Line 130: Line 191:
 
but there is *no* 'make distclean' target. The equivalent is to completely
 
but there is *no* 'make distclean' target. The equivalent is to completely
 
remove your build directory, and start with a fresh one.
 
remove your build directory, and start with a fresh one.
 +
 +
== SimGear Build Options ==
 +
{{Out of date}}
 +
 +
current CPU's at least support SSE3 so that is enabled by default now, Enabling AVX adds another speedup for double precision floating point calculations which is pretty much all of the FlightGear math.<ref>{{cite web
 +
  |url    =  https://forum.flightgear.org/viewtopic.php?p=302451#p302451
 +
  |title  =  <nowiki> Re: Simgear compilation failure </nowiki>
 +
  |author =  <nowiki> erik </nowiki>
 +
  |date  =  Jan 1st, 2017
 +
  |added  =  Jan 1st, 2017
 +
  |script_version = 0.40
 +
  }}</ref>
 +
 +
 +
Some of the more common SimGear build options include
 +
* '''-DENABLE_PROFILE=ON''' (enable support for the [[Built-in Profiler]])
 +
* '''-ENABLE_SIMD=ON''' [[SIMD Support]]
 +
* '''-ENABLE_DNS=ON''' uDNS support
 +
* '''-DENABLE_TESTS=OFF''' (disable unit tests)
 +
* '''-DSIMGEAR_HEADLESS=ON'''  (enables a headless build, i.e. without OSG and other graphics stuff)
 +
* '''-DENABLE_LIBSVN=OFF''' (disables subversion support, i.e. scenery fetching, to be depreciated, see [http://www.mail-archive.com/flightgear-devel@lists.sourceforge.net/msg40191.html] )
 +
* '''-DENABLE_SOUND=OFF''' (disables OpenAL/sound support)
 +
* '''-DCMAKE_INSTALL_PREFIX=$HOME''' (installs everything into $HOME, instead of system-wide)
 +
* '''-DENABLE_RTI=ON''' (enable [[HLA]] support)
 +
* '''-DJPEG_FACTORY=ON''' (enable jpeg support)
 +
* '''-DENABLE_FLITE=ON''' (enable FLITE TTS-based ATIS) [http://sourceforge.net/p/flightgear/mailman/message/32265565] [{{flightgear url|commit=cadb77b18d13bb0d45672ac607801bda222454e9}}]
 +
* '''-ENABLE_GDAL=ON''' (GDAL/OGR) 02/2017 <ref>https://sourceforge.net/p/flightgear/simgear/ci/dad30b0cc212e6ecd4b332cbc4f1335349f89188</ref>
 +
* {{CMake Build Option|option=ENABLE_OPENMP|default=ON|version=02/2017 <ref>https://sourceforge.net/p/flightgear/simgear/ci/dad30b0cc212e6ecd4b332cbc4f1335349f89188</ref>|description=OpenMP support}}
 +
* {{CMake Build Option|option=ENABLE_COMPOSITOR|default=OFF|version=2019.2 <ref>https://sourceforge.net/p/flightgear/flightgear/ci/e042364dd03f2ab425027444f79b94b3babbcd42/</ref>|description=[[Compositor]] support}}
 +
 +
== LTO ==
 +
Erik has tried to compile Simgear and FlightGear using 'gcc -flto' to see if he could squeee just a bit more performance out of the code.
 +
 +
To be able to do so he's run cmake for both Simgear and FlightGear as follows:
 +
 +
<syntaxhighlight lang="sh">
 +
cmake -DCMAKE_AR=/usr/bin/gcc-ar \
 +
-DCMAKE_RANLIB=/usr/bin/gcc-ranlib \
 +
-DCMAKE_NM=/usr/bin/gcc-nm \
 +
-DSIMGEAR_SHARED=1 \
 +
-DCMAKE_BUILD_TYPE=Release \
 +
-DCMAKE_CXX_FLAGS:STRING="-Os march=native -mtune=native -msse3 -mfpmath=sse -flto"
 +
</syntaxhighlight>
 +
 +
After applying one patch to SimGear he got it compiling.
 +
 +
The resulting binary is almost exactly 5Mb smaller:
 +
* 14390984 fgfs-lto
 +
* 19354528 fgfs
 +
 +
It did not alter the frame-rates much for him (he's got quite a decent videocard now with the GeForce GTX 750) but Erik did have the distinct feeling there were way less small-pauses/frame-rate glitches when compared to the regular build. The overall feeling was much smoother.<ref>{{cite web
 +
  |url    =  https://sourceforge.net/p/flightgear/mailman/message/35478384/
 +
  |title  =  <nowiki> [Flightgear-devel] Link Time Optimization </nowiki>
 +
  |author =  <nowiki> Erik Hofman </nowiki>
 +
  |date  =  Nov 8th, 2016
 +
  |added  =  Nov 8th, 2016
 +
  |script_version = 0.40
 +
  }}</ref>
 +
 +
== XCode ==
 +
 +
On Mac, '-G Xcode' will generate nice XCode projects. You can then build in the IDE or using xcodebuild. Ensure you have a recently CMake build, since Xcode support has improved in recent versions (2.8.9 at time of writing). CMake generates an 'install' target which is needed for SimGear, but FlightGear can be run and debugged directly (no install required) - simply set your DYLD_LIBRARY_PATH in the target options, to include your 'dist' directory.
 +
 +
== Troubleshooting ==
 +
 +
If you get the error "Oops, you have installed SimGear includes, however test compiling failed. Try removing 'CMakeCache.txt' and reconfigure with 'cmake'." when trying to run cmake for flightgear it could be that you have an old SimGear version installed from your package manager.
 +
 +
If you get that error or anything strange even though all is apparently fine with matching simgear and flightgear versions you should check how your filesystem is mounted, because if it is an extra partition it could be that is mounted with the "noexec" flag and cmake cannot work in that conditions.
  
 
{{Building}}
 
{{Building}}

Latest revision as of 14:55, 21 February 2019

1rightarrow.png See Building Flightgear for the main article about this subject.

Also see

Please also see Superbuild.

Build Environment & Dependencies

Linux / Unix

Note  as of 12/2017, people may have to build using at least OSG 3.4 due to some compilation issues -for details, refer to Howto:Building FlightGear without HiDPI support
  • Get the OpenSceneGraph sources, either from subversion or a zip
  • NOTE: On Debian AMD64 (or not 32-bit) systems (maybe including Ubuntu) there is currently a packaging error which leads to false detection of OpenAL. Until it got repaired, you have 2 options left:

1. Goto /usr/share/cmake-2.8/Modules/ (it is the right patch on my Debian system) and expand the search path with lib/x86_64-linux-gnu/:

sudo su # to become root
cd /usr/share/cmake-2.8/Modules/ # again, use the proper path of your system
$EDITOR FindOpenAL.cmake
# Search for FIND_LIBRARY(OPENAL_LIBRARY
# Search again for PATH_SUFFIXES
# Append behind "lib": lib/x86_64-linux-gnu/
# Save it
# Quit your editor
exit # to leave root

2. (As I did) Set a symbolic link so cmake can find it:

sudo su # again, become root
cd /usr/lib/
ln -s x86_64-linux-gnu/* . # ignore that error for pkconfig for now
cd pkconfig/
ln -s ../x86_64-linux-gnu/pkgconfig/* .
  • Both steps have advantages and disadvantages, e.g. when it comes to updates, so you might need to repeat your desired path and fix your symbolic links by removing them first (!) and then re-create them. A big "thanks" to James for giving me the hints. :)
  • If you have OSG/PLIB on different directories than the usual, use environmental variables OSG_DIR/PLIBDIR, e.g. addd to ~/.bashrc:
# OSG/PLIB special directory
export OSG_DIR=/opt/my-osg-path
export PLIBDIR=/opt/my-plib-path

Note: In order to set the CFLAGS/CXXFLAGS variables for make/gcc, simply configure cmake and define CMAKE_C_FLAGS and CMAKE_CXX__FLAGS. For example, to enable gprof:

cmake ../flightgear -DCMAKE_BUILD_TYPE=DEBUG -DCMAKE_C_FLAGS=-pg -DCMAKE_CXX_FLAGS=-pg

Mac

  • Install Xcode (from the App Store)
  • Install Boost from MacPorts (or directly from source)
  • Install the Subversion client libraries and PLIB. These are included in the 'Mac 3rd-party dependencies' zip file. PLIB is also available through MacPorts, and Subversion is available by default on Snow Leopard (10.6) and Lion (10.7) but NOT on Mountain Lion (10.8)
  • Install OpenSceneGraph.

The easiest solution is to grab the 3rd-party dependencies build from Jenkins: http://build.flightgear.org:8080/job/Mac-3rdparty-deps/lastSuccessfulBuild/artifact/*zip*/archive.zip. This will give you a 'dist' directory containing PLIB, Subversion and OpenSceneGraph correctly configured. When configured SimGear and FlightGear, simply use this dist directory as CMAKE_INSTALL_PREFIX, and all the dependencies should be found with no other steps.

# make a top-level directory to contain everything
mkdir FGFS
cd FGFS

# move the downloaded 'dist' dir from the zip inside FGFS
mv <dist dir from Jenkins> .

# clone from Git
git clone git://git.code.sf.net/p/flightgear/simgear/
git clone git://git.code.sf.net/p/flightgear/flightgear/

mkdir sgbuild
cd sgbuild
cmake ../simgear -DCMAKE_INSTALL_PREFIX=$PWD/../dist
make; make install

cd ..
mkdir fgbuild
cd fgbuild
cmake ../flightgear -DCMAKE_INSTALL_PREFIX=$PWD/../dist
make; make install

Note this demonstrates start from a clean setup - after the initial build it's sufficient to simply 'git pull' in the clones repositories, then execute a 'make; make install' in the build directories. You can of course have multiple build directories with different configurations, as described in more detail below.

Windows

See Building using CMake - Windows

Getting started with CMake

(These instructions apply to Unix-like systems, including Cygwin and Mac. To build using Visual Studio or some other IDE supported by CMake, most of the information below still applies)

Always compile in a separate directory to the code. For example, if the code (eg, from Git) is at /home/curt/projects/flightgear, you might create /home/curt/projects/fgbuild. Change into the new directory, and run

cmake ../flightgear

To generate standard Unix Makefiles in fgbuild.

All these instructions apply equally to OpenSceneGraph, SimGear and finally FlightGear.

Probably you want to specify an install prefix:

cmake -DCMAKE_INSTALL_PREFIX=/usr ../flightgear

Note the install prefix is automatically searched for required libraries and header files, so if you install PLIB, OpenSceneGraph and SimGear to the same prefix, most configuration options are unnecessary.

If for some reason you have a dependency (or several) at a different prefix, you can specify one or more via CMAKE_PREFIX_PATH:

cmake -DCMAKE_PREFIX_PATH="/opt/local;/opt/fgfs" ../flightgear

(note the use of semi-colons to specify multiple prefix paths)

Standard prefixes are searched automatically (/usr, /usr/local, /opt/local)

Most dependencies also expose an environment variable to specify their installation directory explicitly eg OSG_DIR or PLIBDIR. Any of the methods described above will work, but specifying an INSTALL_PREFIX or PREFIX_PATH is usually simpler.

Debug Builds

By default, we select a release build. To create a debug build, use

cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo ../flightgear

(or MinSizeRel, or Debug)

Debug builds will automatically use corresponding debug builds of required libraries, if they are available. For example you can install debug builds of SimGear and OpenSceneGraph, and a debug FlightGear build will use them.

(Debug builds of libraries have the 'd' suffix by default - Release builds have no additional suffix)

Important: You should keep in mind that debug builds are usually not optimized at all. Thus, it is very likely that a debug binary will perform worse (framerate/performance-wise) than a release build. Many people have reported getting just frame rates of about 30 fps when using a debug binary!

Note most IDE projects (eg Xcode and Visual Studio) support building all the build types from the same project, so you can omit the CMAKE_BUILD_TYPE option when running cmake, and simply pick the build configuration as normal in the IDE.

Profiling

You can also build with optional profiling support by using -DENABLE_PROFILE=ON, for details see: Built-in Profiler.

Multiple build directories

It's common to have several build directories with different build configurations (see [1] for more info), eg

   /home/curt/projects/flightgear (the git clone)
   /home/curt/projects/fgdebug
   /home/curt/projects/fgrelease
   /home/curt/projects/fg-with-svn-osg

Optional Features

To set an optional feature, do

cmake -DFEATURE_NAME=ON  ../flightgear

(or 'OFF' to disable)

To see the variables that can be configured / are currently defined, you can run one of the GUI front ends, or the following command:

cmake -L ../flighgear

Add 'A' to see all the options (including advanced options), or 'H' to see the help for each option (similar to running configure --help under autoconf):

cmake -LH ../flightgear

Build Targets

For a Unix makefile build, 'make dist', 'make uninstall' and 'make test' are all available and should work as expected. 'make clean' is also as normal, but there is *no* 'make distclean' target. The equivalent is to completely remove your build directory, and start with a fresh one.

SimGear Build Options

This article or section contains out-of-date information

Please help improve this article by updating it. There may be additional information on the talk page.

current CPU's at least support SSE3 so that is enabled by default now, Enabling AVX adds another speedup for double precision floating point calculations which is pretty much all of the FlightGear math.[1]


Some of the more common SimGear build options include

  • -DENABLE_PROFILE=ON (enable support for the Built-in Profiler)
  • -ENABLE_SIMD=ON SIMD Support
  • -ENABLE_DNS=ON uDNS support
  • -DENABLE_TESTS=OFF (disable unit tests)
  • -DSIMGEAR_HEADLESS=ON (enables a headless build, i.e. without OSG and other graphics stuff)
  • -DENABLE_LIBSVN=OFF (disables subversion support, i.e. scenery fetching, to be depreciated, see [2] )
  • -DENABLE_SOUND=OFF (disables OpenAL/sound support)
  • -DCMAKE_INSTALL_PREFIX=$HOME (installs everything into $HOME, instead of system-wide)
  • -DENABLE_RTI=ON (enable HLA support)
  • -DJPEG_FACTORY=ON (enable jpeg support)
  • -DENABLE_FLITE=ON (enable FLITE TTS-based ATIS) [3] [4]
  • -ENABLE_GDAL=ON (GDAL/OGR) 02/2017 [2]
  • -DENABLE_OPENMP=ON (OpenMP support requires 02/2017 [3])
  • -DENABLE_COMPOSITOR=OFF (Compositor support requires 2019.2 [4])

LTO

Erik has tried to compile Simgear and FlightGear using 'gcc -flto' to see if he could squeee just a bit more performance out of the code.

To be able to do so he's run cmake for both Simgear and FlightGear as follows:

cmake -DCMAKE_AR=/usr/bin/gcc-ar \
 -DCMAKE_RANLIB=/usr/bin/gcc-ranlib \
 -DCMAKE_NM=/usr/bin/gcc-nm \
 -DSIMGEAR_SHARED=1 \
 -DCMAKE_BUILD_TYPE=Release \
 -DCMAKE_CXX_FLAGS:STRING="-Os march=native -mtune=native -msse3 -mfpmath=sse -flto"

After applying one patch to SimGear he got it compiling.

The resulting binary is almost exactly 5Mb smaller:

  • 14390984 fgfs-lto
  • 19354528 fgfs

It did not alter the frame-rates much for him (he's got quite a decent videocard now with the GeForce GTX 750) but Erik did have the distinct feeling there were way less small-pauses/frame-rate glitches when compared to the regular build. The overall feeling was much smoother.[5]

XCode

On Mac, '-G Xcode' will generate nice XCode projects. You can then build in the IDE or using xcodebuild. Ensure you have a recently CMake build, since Xcode support has improved in recent versions (2.8.9 at time of writing). CMake generates an 'install' target which is needed for SimGear, but FlightGear can be run and debugged directly (no install required) - simply set your DYLD_LIBRARY_PATH in the target options, to include your 'dist' directory.

Troubleshooting

If you get the error "Oops, you have installed SimGear includes, however test compiling failed. Try removing 'CMakeCache.txt' and reconfigure with 'cmake'." when trying to run cmake for flightgear it could be that you have an old SimGear version installed from your package manager.

If you get that error or anything strange even though all is apparently fine with matching simgear and flightgear versions you should check how your filesystem is mounted, because if it is an extra partition it could be that is mounted with the "noexec" flag and cmake cannot work in that conditions.

  1. erik  (Jan 1st, 2017).  Re: Simgear compilation failure .
  2. https://sourceforge.net/p/flightgear/simgear/ci/dad30b0cc212e6ecd4b332cbc4f1335349f89188
  3. https://sourceforge.net/p/flightgear/simgear/ci/dad30b0cc212e6ecd4b332cbc4f1335349f89188
  4. https://sourceforge.net/p/flightgear/flightgear/ci/e042364dd03f2ab425027444f79b94b3babbcd42/
  5. Erik Hofman  (Nov 8th, 2016).  [Flightgear-devel] Link Time Optimization .