// G-forces from SimHub properties
var Gy = - $prop('GameRawData.Physics.AccG01');	// lateral (yaw) acceleration
var Gs = - $prop('GameRawData.Physics.AccG03');	// deceleration
Gy *= $prop('Settings.yaw_gain') * 0.77;	// 72
Gs *= $prop('Settings.decel_gain') * 0.39;	// 178
if (0 > Gs)
  Gs = 0;				// non-negative deceleration

// convert speed and yaw changes to left and right tension values
// turning right should increase right harness tension (body pushed left)
var r = Math.sqrt(Gs*Gs + Gy*Gy);
var l = Gs + Gs - r;
if (0 > Gy) {
  var t = r;	// negative Gy increases left tension
  r = l;
  l = t;
}

// Low-pass IIR filtering of left and right tension values
if (null == root["lb4"]) {
  root["rb4"] = r;  root["lb4"] = l;	// initialize
}
var rb4 = root["rb4"];
var lb4 = root["lb4"]; // previously filtered values
var tc = 1 + $prop('Settings.smooth');
rb4 += (r - rb4) / tc;
lb4 += (l - lb4) / tc;
root["lb4"] = lb4;
root["rb4"] = rb4;

l = lb4; r = rb4; // filtered tensions;  comment out for unfiltered (or set Settings.smooth = 1)
var tmax = $prop('Settings.tmax') & 126;
if (l > tmax)
  l = tmax;
else if (l < 2)
  l = 2;
l &= 0x7E;      // left lsb is 0
tmax |= 1;
if (r > tmax)
  r = tmax;
else if (r < 3)
  r = 3;
r |= 1;         // right lsb is 1

if ($prop('Settings.max_test') || $prop('Settings.TestOffsets')) {
  // disable normal message output
  // slider changes will provoke first message outputs
  root["lb4"] = root["rb4"] = 0;
} else {
//* servo control output
  var ls = String.fromCharCode(l);      // tension control characters
  var rs = String.fromCharCode(r);
//*/

/* gnuplot output **************************************
  var s = $prop('SpeedMph');
  var ls = l.toString();
  var rs = r.toString();
  var ss = s.toString();
  var Gys = Gy.toString();
  var Gss = Gs.toString();
  rs = ls.concat('\t',rs,'\r\n');  // gnuplot columns
  ls = ss.concat('\t'); 
*/
  return ls.concat(rs);
}