[Jsbsim-devel] Stripchart application

[Jon S. B. <jon...@co...>]

I have placed online at the JSBSim.org web site a rudimentary stripchart
application:

http://www.jsbsim.org/stripchart.zip

If you unzip this into a folder, it should result in an application that you
can run which will just sit there and wait. If  you select File|Options, you
can select a different port number to listen at (the default is 1138). When
you are ready, you can click on the Start button and the application will
begin waiting.

The idea is then to start JSBSim, running an aircraft model that has an
<output> spec that looks like this:

    <output name="localhost" type="SOCKET" port="1138" rate="20">
        <simulation> OFF </simulation>
        <atmosphere> OFF </atmosphere>
        <massprops> OFF</massprops>
        <rates> OFF </rates>
        <velocities> OFF </velocities>
        <forces> OFF </forces>
        <moments> OFF </moments>
        <position> OFF </position>
        <propulsion> OFF </propulsion>
        <aerosurfaces> OFF </aerosurfaces>
        <fcs> OFF </fcs>
        <ground_reactions> OFF </ground_reactions>
        <coefficients> OFF </coefficients>
        <property> position/h-agl-ft </property>
        <property> velocities/vc-kts </property>
        <property> attitude/phi-rad </property>
        <property> fcs/attitude/sensor/phi-rad </property>
    </output>

Notice the name, type, port, and rate settings. When JSBSim is run with this
<output> definition (or when standalone JSBSim is run where the
"--logdirectivefile" is used to provide an <output> directives file name)
then data is sent out over a socket (in this case on locahost | port 1138)
and the stripchart application sees that and begins plotting it. Of course,
this works best when JSBSim is run in realtime mode (either from the
standalone application, or when JSBSim is incorporated into another
application). I run JSBSim like this when using the stripchart,

src/jsbsim --script=scripts/c1723 --realtime --nice

The shutdown of both JSBSim and the stripchart application is not very
graceful at this time, unfortunately. I wrote this application quite a while
ago, when I was not as familiar with sockets as I am now (and I'm still not
very familiar with them).

I hope this is useful for someone. Let me know if there are any problems. I
may have forgotten to include a DLL in the zipfile.

Jon

Jon S. Berndt
Development Coordinator
JSBSim Project
www.JSBSim.org