jMAVSim: Added the option to run without the GUI

[katzfey]

Added a new command line argument to allow the user to run without the GUI. The
new argument is -no-gui. This allows use of the simulator in environments that
do not have a GUI, like a headless Docker.

Fixes #59.

[julianoes]

Thanks for the PR @katzfey! I'll try this out and review it.

[julianoes]

@katzfey please rebase on top of master, then CI should pass.

[julianoes]

Looks correct.

[julianoes]

Unfortunately the problem is that the j3d libs still require a X11 DISPLAY variable as was also mentioned in #59 (comment).

Exception in thread "main" java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:61)
Caused by: java.lang.ExceptionInInitializerError
	at javax.media.j3d.GroupRetained.<init>(GroupRetained.java:155)
	at javax.media.j3d.TransformGroupRetained.<init>(TransformGroupRetained.java:116)
	at javax.media.j3d.TransformGroup.createRetained(TransformGroup.java:115)
	at javax.media.j3d.SceneGraphObject.<init>(SceneGraphObject.java:114)
	at javax.media.j3d.Node.<init>(Node.java:172)
	at javax.media.j3d.Group.<init>(Group.java:551)
	at javax.media.j3d.TransformGroup.<init>(TransformGroup.java:87)
	at me.drton.jmavsim.KinematicObject.<init>(KinematicObject.java:42)
	at me.drton.jmavsim.DynamicObject.<init>(DynamicObject.java:24)
	at me.drton.jmavsim.vehicle.AbstractVehicle.<init>(AbstractVehicle.java:26)
	at me.drton.jmavsim.vehicle.AbstractMulticopter.<init>(AbstractMulticopter.java:19)
	at me.drton.jmavsim.vehicle.Quadcopter.<init>(Quadcopter.java:33)
	at me.drton.jmavsim.Simulator.buildMulticopter(Simulator.java:431)
	at me.drton.jmavsim.Simulator.<init>(Simulator.java:312)
	at me.drton.jmavsim.Simulator.main(Simulator.java:930)
	... 5 more
Caused by: java.awt.HeadlessException: 
No X11 DISPLAY variable was set, but this program performed an operation which requires it.
	at javax.media.j3d.VirtualUniverse.<clinit>(VirtualUniverse.java:269)
	... 20 more

I think the change is still worthwile but it doesn't allow it to be run in CI/docker just yet.

[katzfey]

Darn! Sorry about that. You would think that if I wanted it to run in a headless Docker that I would have tested it in a headless Docker. I'll keep working on it.

[JonasVautherin]

What's the status on that? @katzfey does it run in docker now? I'll be happy to test it when it works for you!

[katzfey]

Well, I am testing in a Docker now and can reproduce the issue. I have made changes and it gets farther but still not quite there.

[katzfey]

I have it all working now on headless docker. Need to clean up some commit comments and then I can submit a new PR.

[katzfey]

@JonasVautherin Please feel free to test the work now. It seems to be working for me on a headless system with the -no-gui option. Branch is run_without_gui in my repo https://github.com/katzfey/jMAVSim

[JonasVautherin]

Branch is run_without_gui in my repo

Which is this PR, right? 😅

[julianoes]

Nice work, it works for me in docker without $DISPLAY.

I made two small comments that would be nice if you could check them.

[julianoes]

Awesome, thanks @katzfey!