Allow superelevation on straight track segments, revise 3D superelevation generation, remove influence of secondary motion on camera position, improve handling of extreme gradients

Author: SteelFill

Source/Documentation/How to Provide Track Profiles for Open Rails Dynamic Track.docm

@@ -39,6 +39,7 @@ What's been improved
 - controls for electric locos
 - air brake features for both European and American brake systems 
 - accurate friction simulation for 4 types of brake shoes
+- superelevation system rewritten to be smoother and more configurable
 
 
 Other changes

Source/Documentation/Manual/news.rst

@@ -138,7 +138,7 @@ public Vector3 Location
         /// </summary>
         public void Normalize()
         {
-            var TileLocation = XNAMatrix.Translation;
+            var TileLocation = Location;
             int xTileDistance = (int)Math.Round((int)(TileLocation.X / 1024) / 2.0, MidpointRounding.AwayFromZero);
             int zTileDistance = (int)Math.Round((int)(TileLocation.Z / 1024) / 2.0, MidpointRounding.AwayFromZero);
             if (xTileDistance == 0 && zTileDistance == 0) return;
@@ -148,7 +148,7 @@ public void Normalize()
                 TileZ += zTileDistance;
                 TileLocation.X = (float)(TileLocation.X - (xTileDistance * TileSize));
                 TileLocation.Z = (float)(TileLocation.Z - (zTileDistance * TileSize));
-                XNAMatrix.Translation = TileLocation;
+                Location = TileLocation;
             }
         }
 

Source/ORTS.Common/Coordinates.cs

@@ -136,9 +136,9 @@ public Tr_RouteFile(STFReader stf)
             {
                 // No superelevation standard defined, create the default one
                 if (SuperElevationHgtpRadiusM != null)
-                    SuperElevation.Add(new SuperElevationStandard(SuperElevationHgtpRadiusM, MilepostUnitsMetric));
+                    SuperElevation.Add(new SuperElevationStandard(SuperElevationHgtpRadiusM, MilepostUnitsMetric, SpeedLimit > 45.0f));
                 else
-                    SuperElevation.Add(new SuperElevationStandard(MilepostUnitsMetric));
+                    SuperElevation.Add(new SuperElevationStandard(MilepostUnitsMetric, SpeedLimit > 45.0f));
             }
         }
 
@@ -248,41 +248,70 @@ public class SuperElevationStandard
         public bool UseLegacyCalculation = true; // Should ORTSTrackSuperElevation be used for superelevation calculations?
 
         // Initialize new instance with default values (default metric values)
-        public SuperElevationStandard(bool metric = true)
+        public SuperElevationStandard(bool metric = true, bool highSpeed = false)
         {
             if (metric)
             {
                 // Set underbalance to millimeter values for metric routes
-                MaxFreightUnderbalanceM = 0.100f; // Default 100 mm
-                MaxPaxUnderbalanceM = 0.150f; // Default 150 mm
+                if (highSpeed)
+                {
+                    RunoffSpeedMpS = 0.080f; // 80 mm / sec for higher speed routes
+                    MaxFreightUnderbalanceM = 0.110f; // 110 mm for higher speed routes
+                    MaxPaxUnderbalanceM = 0.150f; // 150 mm for higher speed routes
+                }
+                else
+                {
+                    MaxFreightUnderbalanceM = 0.100f; // Default 100 mm
+                    MaxPaxUnderbalanceM = 0.130f; // Default 130 mm
+                }
                 // Other parameters are already metric by default
+
             }
             else
             {
                 // Set values in imperial units
-                MaxFreightUnderbalanceM = Me.FromIn(2.0f); // Default 2 inches
-                MaxPaxUnderbalanceM = Me.FromIn(3.0f); // Default 3 inches
                 MinCantM = Me.FromIn(0.5f);
                 MaxCantM = Me.FromIn(6.0f);
                 MinSpeedMpS = MpS.FromMpH(15.0f);
                 PrecisionM = Me.FromIn(0.25f);
-                RunoffSpeedMpS = MpS.FromMpH(0.0852f); // 1.5 inches per second
+
+                if (highSpeed)
+                {
+                    RunoffSpeedMpS = MpS.FromMpH(0.1136f); // 2.0 inches for higher speed routes
+                    MaxFreightUnderbalanceM = Me.FromIn(3.0f); // 3 inches for higher speed routes
+                    MaxPaxUnderbalanceM = Me.FromIn(5.0f); // 5 inches for higher speed routes
+                }
+                else
+                {
+                    RunoffSpeedMpS = MpS.FromMpH(0.0852f); // Default 1.5 inches per second
+                    MaxFreightUnderbalanceM = Me.FromIn(2.0f); // Default 2 inches
+                    MaxPaxUnderbalanceM = Me.FromIn(3.0f); // Default 3 inches
+                }
             }
         }
 
         // Initialize new instance from superelevation interpolator
         // Interpolator X values should be curve radius, Y values amount of superelevation in meters
-        public SuperElevationStandard(Interpolator elevTable, bool metric = true)
+        public SuperElevationStandard(Interpolator elevTable, bool metric = true, bool highSpeed = false)
         {
             MinCantM = elevTable.Y.Min();
             MaxCantM = elevTable.Y.Max();
 
-            if (!metric)
+            MinSpeedMpS = 0.0f;
+
+            if (metric)
+            {
+                if (highSpeed)
+                    RunoffSpeedMpS = 0.080f; // 80 mm / sec of runoff allows for shorter build up on high speed routes
+            }
+            else
             {
                 // Some extra data still required, use imperial units if the route uses it
-                MinSpeedMpS = MpS.FromMpH(15.0f);
                 PrecisionM = Me.FromIn(0.25f);
-                RunoffSpeedMpS = MpS.FromMpH(0.0852f); // 1.5 inches per second
+                if (highSpeed)
+                    RunoffSpeedMpS = MpS.FromMpH(0.1136f); // 2.0 inches per second of runoff allows for shorter build up on high speed routes
+                else
+                    RunoffSpeedMpS = MpS.FromMpH(0.0852f); // 1.5 inches per second normal
             }
         }
 

Source/Orts.Formats.Msts/RouteFile.cs

@@ -375,8 +375,10 @@ public override void InitializeMoving() // TODO
                 float initialThrottlepercent = InitialThrottlepercent;
                 MUDynamicBrakePercent = -1;
                 AITrainBrakePercent = 0;
-
-                FirstCar.CurrentElevationPercent = 100f * FirstCar.WorldPosition.XNAMatrix.M32;
+                // Percent slope = rise / run -> the Y position of the forward vector gives us the 'rise'
+                // Derive the 'run' by assuming a hypotenuse length of 1, so run = sqrt(1 - rise^2)
+                float rise = FirstCar.WorldPosition.XNAMatrix.M32;
+                FirstCar.CurrentElevationPercent = 100f * (rise / (float)Math.Sqrt(1 - rise * rise));
                 // Give it a bit more gas if it is uphill
                 if (FirstCar.CurrentElevationPercent < -2.0) initialThrottlepercent = 40f;
                 // Better block gas if it is downhill

Source/Orts.Simulation/Simulation/AIs/AITrain.cs

@@ -629,9 +629,7 @@ static void ComputeTablePosition(TempSpeedPostItem restrSpeedPost)
             var speedPostTablePosition = new Vector3(2.2f, 0, 0);
             Vector3.Transform(ref speedPostTablePosition, ref restrSpeedPost.WorldPosition.XNAMatrix, out speedPostTablePosition);
             restrSpeedPost.WorldPosition.XNAMatrix.Translation = speedPostTablePosition;
-            restrSpeedPost.WorldPosition.XNAMatrix.M43 *= -1;
             restrSpeedPost.WorldPosition.Normalize();
-            restrSpeedPost.WorldPosition.XNAMatrix.M43 *= -1;
         }
 
 

Source/Orts.Simulation/Simulation/Activity.cs

@@ -1860,7 +1860,11 @@ public virtual void InitializeMoving()
             {
                 MSTSLocomotive lead = (MSTSLocomotive)Cars[LeadLocomotiveIndex];
                 if (lead is MSTSSteamLocomotive) MUReverserPercent = 25;
-                lead.CurrentElevationPercent = 100f * lead.WorldPosition.XNAMatrix.M32;
+
+                // Percent slope = rise / run -> the Y position of the forward vector gives us the 'rise'
+                // Derive the 'run' by assuming a hypotenuse length of 1, so run = sqrt(1 - rise^2)
+                float rise = lead.WorldPosition.XNAMatrix.M32;
+                lead.CurrentElevationPercent = 100f * (rise / (float)Math.Sqrt(1 - rise * rise));
 
                 //TODO: next if block has been inserted to flip trainset physics in order to get viewing direction coincident with loco direction when using rear cab.
                 // To achieve the same result with other means, without flipping trainset physics, the block should be deleted