Howto:Timers and properties

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Objective

A timer that unpauses FlightGear 30 seconds after it starts, and then exits the simulator after a set number of seconds. It unpauses the simulator by setting these two properties:

• /sim/freeze/master=0
• /sim/freeze/clock=0

## $FG_HOME/Nasal/timedExit.nas

##
# the time for FG to run
var interval_sec = 30.00;

##
# afterwards, this timer will be triggered
var resume_sec = 20.00;

var unpause = func(){
  print("unpause() called!");
  var properties = [ 
    { name: "/sim/freeze/master", value: 0 },
    { name: "/sim/freeze/clock", value: 0 },
  ];

  foreach(var prop; properties){
    print("Setting '", prop.name, "' to ", prop.value);
    setprop(prop.name, prop.value);
  }

  ##
  # start a new timer
  print("Exit timer registered");
  var exitTimer = maketimer(resume_sec, terminate_callback);
  exitTimer.singleShot = 1;
  exitTimer.start();
}

var terminate_callback = func(){
  print("Terminating FG");
  fgcommand("exit");
};

## 
# http://wiki.flightgear.org/Nasal_library#maketimer.28.29_.282.11.2B.29
var myTimer = maketimer(interval_sec, unpause);
myTimer.singleShot = 1;
myTimer.start();

print("UnpauseTimer registered!");