Add distance figure between car and camera

Author: peternewell

Source/Orts.Formats.Msts/SoundManagmentFile.cs

@@ -243,7 +243,7 @@ public struct CurvePoint
 
     public class VolumeCurve
     {
-        public enum Controls { None, DistanceControlled, SpeedControlled, Variable1Controlled, Variable1_2Controlled, Variable1_3Controlled, Variable1_4Controlled, Variable2Controlled, Variable2BoosterControlled, Variable3Controlled, BrakeCylControlled, CurveForceControlled, AngleofAttackControlled, CarFrictionControlled, WheelRpMControlled };
+        public enum Controls { None, DistanceControlled, SpeedControlled, Variable1Controlled, Variable1_2Controlled, Variable1_3Controlled, Variable1_4Controlled, Variable2Controlled, Variable2BoosterControlled, Variable3Controlled, BrakeCylControlled, CurveForceControlled, AngleofAttackControlled, CarFrictionControlled, WheelRpMControlled, CarDistanceTrackControlled };
 
         public Controls Control = Controls.None;
         public float Granularity = 1.0f;
@@ -270,6 +270,7 @@ public VolumeCurve(STFReader stf)
                 case "angleofattackcontrolled": Control = Controls.AngleofAttackControlled; break;
                 case "carfrictioncontrolled": Control = Controls.CarFrictionControlled; break;
                 case "wheelrpmcontrolled": Control = Controls.WheelRpMControlled; break;
+                case "distancetrackcontrolled": Control = Controls.CarDistanceTrackControlled; break;
                 default: STFException.TraceWarning(stf, "Crash expected: Skipped unknown VolumeCurve/Frequencycurve type " + type); stf.SkipRestOfBlock(); return;
             }
             stf.ParseBlock(new STFReader.TokenProcessor[] {

Source/Orts.Simulation/Simulation/RollingStocks/TrainCar.cs

@@ -599,6 +599,7 @@ public Direction Direction
         float jointTriggerDelayedS = 0.1f; // Set delay to 0.1 seconds
         float jointSpeedMpS;
         public float SoundAxleCount;
+        public float CarTrackControlledDistanceM = 0;
 
         // Track sound effects - switch / crossover
         public float TrackSwitchSoundTriggered;

Source/RunActivity/Viewer3D/Sound.cs

@@ -330,6 +330,13 @@ public void UpdateTType(bool stateChange)
                         Car.TrackSoundLocation = new WorldLocation(Car.WorldPosition.WorldLocation);
                     _prevTType = _curTType;
                 }
+
+                if (SharedSMSFileManager.PlayDefaultTrackSoundsContinuous)
+                {
+                    // Calculate the distance from the car to the camera position. Used for track based sounds
+                    Car.CarTrackControlledDistanceM = (float)Math.Sqrt(WorldLocation.GetDistanceSquared(Car.WorldPosition.WorldLocation, Viewer.Camera.CameraWorldLocation));
+                }
+
             }
         }
 
@@ -1538,6 +1545,7 @@ private float ReadValue(Orts.Formats.Msts.VolumeCurve.Controls control, MSTSWago
                 case Orts.Formats.Msts.VolumeCurve.Controls.AngleofAttackControlled: return car.CurveSquealAoAmRadFiltered;
                 case Orts.Formats.Msts.VolumeCurve.Controls.CarFrictionControlled: return car.Train.WagonCoefficientFriction;
                 case Orts.Formats.Msts.VolumeCurve.Controls.WheelRpMControlled: var wheelRpM = pS.TopM((float)(car.AbsSpeedMpS / (2 * Math.PI * car.WheelRadiusM))); return wheelRpM;
+                case Orts.Formats.Msts.VolumeCurve.Controls.CarDistanceTrackControlled: return car.CarTrackControlledDistanceM;   
                 default: return 0;
             }
         }