Properly terminate render engine

[osrf-migration]

Original report (archived issue) by Louise Poubel (Bitbucket: chapulina, GitHub: chapulina).

---

@iche033 mentioned on pull request #62 that we should call Fini on the ignition-rendering engine before terminating the program so it shuts down properly.

I tried calling fini when the engine has no more scenes like this:

diff -r 17c6c8bc83ab46edfadd765870d150e87d868e4e src/plugins/Scene3D.cc
--- a/src/plugins/Scene3D.cc	Tue Dec 26 08:53:22 2017 -0800
+++ b/src/plugins/Scene3D.cc	Tue Dec 26 09:27:22 2017 -0800
@@ -90,6 +90,8 @@
     engine->DestroyScene(scene);
 
     // TODO: If that was the last scene, terminate engine?
+    if (engine->SceneCount() == 0)
+      engine->Fini();
   }
 }

But if after doing this, we try to open a new scene plugin (i.e. re-init the engine), the program crashes with this backtrace:

/usr/local/lib/libignition-rendering-ogre.so.0(_ZN8ignition9rendering9OgreScene13CreateContextEv+0x75) [0x7f49e1e5c731] /home/louise/code/ign-rendering/src/ogre/OgreScene.cc:339
/usr/local/lib/libignition-rendering-ogre.so.0(_ZN8ignition9rendering9OgreScene8InitImplEv+0x3a) [0x7f49e1e57faa] /home/louise/code/ign-rendering/src/ogre/OgreScene.cc:124
/usr/local/lib/libignition-rendering-base.so.0(_ZN8ignition9rendering9BaseScene4InitEv+0x1d1) [0x7f49e18de6a7] /home/louise/code/ign-rendering/src/base/BaseScene.cc:70
/usr/local/lib/libignition-rendering-base.so.0(_ZN8ignition9rendering16BaseRenderEngine12PrepareSceneESt10shared_ptrINS0_5SceneEE+0xc8) [0x7f49e18daea6] /home/louise/code/ign-rendering/src/base/BaseRenderEngine.cc:214
/usr/local/lib/libignition-rendering-base.so.0(_ZN8ignition9rendering16BaseRenderEngine11CreateSceneEjRKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE+0x785) [0x7f49e18daae5] /home/louise/code/ign-rendering/src/base/BaseRenderEngine.cc:193
/usr/local/lib/libignition-rendering-base.so.0(_ZN8ignition9rendering16BaseRenderEngine11CreateSceneERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE+0x86) [0x7f49e18da2e0] /home/louise/code/ign-rendering/src/base/BaseRenderEngine.cc:167
/usr/local/lib/ign-gui-0/plugins/libScene3D.so(_ZN8ignition3gui7plugins7Scene3D10LoadConfigEPKN8tinyxml210XMLElementE+0x1199) [0x7f49e24ed8e7] /home/louise/code/ign-gui/src/plugins/Scene3D.cc:170
/usr/local/lib/libignition-gui0.so(_ZN8ignition3gui6Plugin4LoadEPKN8tinyxml210XMLElementE+0x93d) [0x7f4a1557b765] /home/louise/code/ign-gui/src/Plugin.cc:100
/usr/local/lib/libignition-gui0.so(_ZN8ignition3gui10loadPluginERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEPKN8tinyxml210XMLElementE+0x15c8) [0x7f4a154cebe1] /home/louise/code/ign-gui/src/Iface.cc:553
/usr/local/lib/libignition-gui0.so(_ZN8ignition3gui10MainWindow11OnAddPluginE7QString+0x1d7) [0x7f4a154f041d] /home/louise/code/ign-gui/src/MainWindow.cc:268
/usr/local/lib/libignition-gui0.so(_ZN8ignition3gui10MainWindow18qt_static_metacallEP7QObjectN11QMetaObject4CallEiPPv+0x19d) [0x7f4a1559fd97] /home/louise/code/ign-gui/build/include/ignition/gui/moc_MainWindow.cpp:88
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN11QMetaObject8activateEP7QObjectiiPPv+0x7ea) [0x7f4a1228fd2a]
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN13QSignalMapper6mappedERK7QString+0x35) [0x7f4a1229a1a5]
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN13QSignalMapper3mapEP7QObject+0x202) [0x7f4a1229b6f2]
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN11QMetaObject8activateEP7QObjectiiPPv+0x7ea) [0x7f4a1228fd2a]
/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5(_ZN7QAction9triggeredEb+0x42) [0x7f4a1309f412]
/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5(_ZN7QAction8activateENS_11ActionEventE+0xf8) [0x7f4a130a1898]
/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 [0x7f4a130a1e1f]
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN7QObject5eventEP6QEvent+0xf1) [0x7f4a12290c01]
/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5(_ZN7QAction5eventEP6QEvent+0x22) [0x7f4a130a2122]
/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5(_ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent+0x8c) [0x7f4a130a905c]
/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5(_ZN12QApplication6notifyEP7QObjectP6QEvent+0x256) [0x7f4a130ae516]
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN16QCoreApplication14notifyInternalEP7QObjectP6QEvent+0xdb) [0x7f4a1226138b]
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN23QCoreApplicationPrivate16sendPostedEventsEP7QObjectiP11QThreadData+0x2c6) [0x7f4a12263786]
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5 [0x7f4a122b73c3]
/lib/x86_64-linux-gnu/libglib-2.0.so.0(g_main_context_dispatch+0x2a7) [0x7f4a0f33f197]
/lib/x86_64-linux-gnu/libglib-2.0.so.0 [0x7f4a0f33f3f0]
/lib/x86_64-linux-gnu/libglib-2.0.so.0(g_main_context_iteration+0x2c) [0x7f4a0f33f49c]
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE+0x5f) [0x7f4a122b77cf]
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE+0x10a) [0x7f4a1225eb4a]
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN16QCoreApplication4execEv+0x9c) [0x7f4a12266bec]
/usr/local/lib/libignition-gui0.so(_ZN8ignition3gui13runMainWindowEv+0x205) [0x7f4a154d09bb] /home/louise/code/ign-gui/src/Iface.cc:659
/usr/local/lib/libignition-gui0.so(_ZN8ignition3gui9runConfigERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE+0x3ee) [0x7f4a154c9be1] /home/louise/code/ign-gui/src/Iface.cc:226
/usr/local/lib/libignition-gui0.so(cmdConfig+0x81) [0x7f4a154eabe9] /home/louise/code/ign-gui/src/ign.cc:53
/usr/lib/x86_64-linux-gnu/libffi.so.6(ffi_call_unix64+0x4c) [0x7f4a158b2e40]
/usr/lib/x86_64-linux-gnu/libffi.so.6(ffi_call+0x2eb) [0x7f4a158b28ab]
/usr/lib/x86_64-linux-gnu/ruby/2.3.0/fiddle.so [0x7f4a15ab9758]
/usr/lib/x86_64-linux-gnu/libruby-2.3.so.2.3 [0x7f4a180427ef]
/usr/lib/x86_64-linux-gnu/ruby/2.3.0/fiddle.so [0x7f4a15ab9585]
/usr/lib/x86_64-linux-gnu/libruby-2.3.so.2.3 [0x7f4a1802450b]
/usr/lib/x86_64-linux-gnu/libruby-2.3.so.2.3 [0x7f4a180324a3]
/usr/lib/x86_64-linux-gnu/libruby-2.3.so.2.3 [0x7f4a180334d3]
/usr/lib/x86_64-linux-gnu/libruby-2.3.so.2.3 [0x7f4a1802819c]
/usr/lib/x86_64-linux-gnu/libruby-2.3.so.2.3 [0x7f4a1802d142]
/usr/lib/x86_64-linux-gnu/libruby-2.3.so.2.3 [0x7f4a17f13cfd]
/usr/lib/x86_64-linux-gnu/libruby-2.3.so.2.3(ruby_exec_node+0x1d) [0x7f4a17f156fd]
/usr/lib/x86_64-linux-gnu/libruby-2.3.so.2.3(ruby_run_node+0x1e) [0x7f4a17f1783e]
/usr/bin/ruby [0x40087b]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0) [0x7f4a17b02830] ../csu/libc-start.c:291
/usr/bin/ruby(_start+0x29) [0x4008a9]