Merge pull request #536 from pzgulyas/ttype

Gently handle a track sound crash. Fixes bug https://bugs.launchpad.net/or/+bug/1754805

Author: Sharpe49

Source/RunActivity/Viewer3D/Sound.cs

@@ -300,15 +300,21 @@ public void UpdateTType(bool stateChange)
                     {
                         _activeInSource.Uninitialize();
                         //_activeInSource.Car = null;
-                        _activeInSource = _inSources[_curTType];
+                        if (0 <= _curTType && _curTType < _inSources.Count)
+                            _activeInSource = _inSources[_curTType];
+                        else
+                            Trace.TraceWarning("Could not change inside sound region to {0}", _curTType);
                         //_activeInSource.Car = Car;
                     }
 
                     if (_activeOutSource != null)
                     {
                         _activeOutSource.Uninitialize();
                         //_activeOutSource.Car = null;
-                        _activeOutSource = _outSources[_curTType];
+                        if (0 <= _curTType && _curTType < _outSources.Count)
+                            _activeOutSource = _outSources[_curTType];
+                        else
+                            Trace.TraceWarning("Could not change outside sound region to {0}", _curTType);
                         //_activeOutSource.Car = Car;
                     }
 #if DEBUGSCR
@@ -457,15 +463,21 @@ public bool UpdateCarOnSwitchAndCurve()
                     {
                         _activeInSource.Uninitialize();
                         //_activeInSource.Car = null;
-                        _activeInSource = _inSources[_curTType];
+                        if (0 <= _curTType && _curTType < _inSources.Count)
+                            _activeInSource = _inSources[_curTType];
+                        else
+                            Trace.TraceWarning("Could not change inside sound region to {0}", _curTType);
                         //_activeInSource.Car = Car;
                     }
 
                     if (_activeOutSource != null)
                     {
                         _activeOutSource.Uninitialize();
                         //_activeOutSource.Car = null;
-                        _activeOutSource = _outSources[_curTType];
+                        if (0 <= _curTType && _curTType < _outSources.Count)
+                            _activeOutSource = _outSources[_curTType];
+                        else
+                            Trace.TraceWarning("Could not change outside sound region to {0}", _curTType);
                         //_activeOutSource.Car = Car;
                     }
 #if DEBUGSCR