Fix issues with legacy superelevation settings

Author: SteelFill

Source/Orts.Formats.Msts/TrackDatabaseFile.cs

@@ -788,11 +788,11 @@ public class TrVectorSection
 
         /// <summary>Interpolator storing the amount of physics superelevation in meters vs distance along
         /// the track section normalized from 0 to 1.</summary>
-        public Interpolator PhysElevTable;
+        public Interpolator PhysElevTable = new Interpolator(new float[] { 0, 1 }, new float[] { 0, 0 });
 
         /// <summary>Interpolator storing the angle of visual superelevation in radians vs distance along
         /// the track section normalized from 0 to 1.</summary>
-        public Interpolator VisElevTable;
+        public Interpolator VisElevTable = new Interpolator(new float[] { 0, 1 }, new float[] { 0, 0 });
         /// <summary>Nominal amount of superelevation based on speed and radius.
         /// Actual superelevation used will depend on adjacent curves and superelevation settings.</summary>
         public float NomElevM { get; set; } = -1.0f;

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

@@ -2830,7 +2830,7 @@ public void ComputePosition(Traveller traveler, bool backToFront, float elapsedT
                     if (-.2 < d && d < .2)
                         continue;
                     // Add a fake "wheel" to serve as a pivot point
-                    p.AddWheelSetLocation(1, p.OffsetM, p0.Pos[0] + p.OffsetM * p0.Dir[0], p0.Pos[1] + p.OffsetM * p0.Dir[1], p0.Pos[2] + p.OffsetM * p0.Dir[2], 0);
+                    p.AddWheelSetLocation(1, p.OffsetM, p0.Pos[0] + p.OffsetM * p0.Dir[0], p0.Pos[1] + p.OffsetM * p0.Dir[1], p0.Pos[2] + p.OffsetM * p0.Dir[2], p.Roll);
                     p.FindCenterLine();
                 }
             }

Source/Orts.Simulation/Simulation/SuperElevation.cs

@@ -90,7 +90,7 @@ public SuperElevation(Simulator simulator)
                         }
                         else if (curveDir != Math.Sign(sec.SectionCurve.Angle)) // we are in curve, but bending different dir
                         {
-                            MarkSections(simulator, sectionList, curveLen, sectionLengths); // treat the sections encountered so far, then restart with other dir
+                            MarkSections(simulator, sectionList, curveLen, sectionLengths, curveDir); // treat the sections encountered so far, then restart with other dir
                             curveDir = Math.Sign(sec.SectionCurve.Angle);
                             sectionList.Clear();
                             sectionLengths.Clear();
@@ -104,7 +104,7 @@ public SuperElevation(Simulator simulator)
                     {
                         if (startCurve == true) // we are in a curve, need to finish
                         {
-                            MarkSections(simulator, sectionList, curveLen, sectionLengths);
+                            MarkSections(simulator, sectionList, curveLen, sectionLengths, curveDir);
                             curveLen = 0f;
                             sectionList.Clear();
                             sectionLengths.Clear();
@@ -126,16 +126,23 @@ public SuperElevation(Simulator simulator)
                 }
                 if (startCurve == true) // we are in a curve after looking at every section
                 {
-                    MarkSections(simulator, sectionList, curveLen, sectionLengths);
+                    MarkSections(simulator, sectionList, curveLen, sectionLengths, curveDir);
                 }
                 sectionList.Clear();
             }
         }
 
-        void MarkSections(Simulator simulator, List<TrVectorSection> SectionList, float totLen, List<float> lengths)
+        void MarkSections(Simulator simulator, List<TrVectorSection> SectionList, float totLen, List<float> lengths, int direction)
         {
-            if (totLen < simulator.SuperElevationMinLen || SectionList.Count == 0)
-                return; // Ignore curves too short or invalid data
+            if (SectionList.Count <= 0)
+                return; // Avoid errors with invalid section lists
+            else if (totLen < simulator.SuperElevationMinLen)
+            {
+                // Zero out any curves that are too short
+                foreach (TrVectorSection s in SectionList)
+                    s.NomElevM = 0;
+                return;
+            }
 
             // The superelevation standard we will use. null means no superelevation
             SuperElevationStandard standard = null;
@@ -218,9 +225,8 @@ void MarkSections(Simulator simulator, List<TrVectorSection> SectionList, float
                             }
                             else // No superelevation needed (shouldn't reach this point, this is a failsafe)
                                 superElevation = 0.0f;
-
-                            SectionList[i].NomElevM = superElevation;
                         }
+                        SectionList[i].NomElevM = superElevation;
                     }
                 }
             }
@@ -325,6 +331,9 @@ void MarkSections(Simulator simulator, List<TrVectorSection> SectionList, float
                 // Visual superelevation is stored in terms of angle in radians rather than meters
                 float[] angles = elevations.Select(e => (float)Math.Asin(e / simulator.SuperElevationGauge)).ToArray();
                 SectionList[count].VisElevTable = new Interpolator(SectionList[count].PhysElevTable.X, angles);
+                // Invert visual elevation values based on curve direction
+                // direction is negated for consistency of direction sense in other places
+                SectionList[count].VisElevTable.ScaleY(-direction);
 
                 accumulatedLength += lengths[count];
                 count++;

Source/Orts.Simulation/Simulation/Traveller.cs

@@ -1041,7 +1041,7 @@ public float GetVisualElevation(bool useVisualElev = true)
             {
                 visualElev = trackVectorSection.VisElevTable[to];
                 // Correct the direction of tilt for the direction of travel
-                visualElev *= Math.Sign(trackSection.SectionCurve.Angle) > 0 ^ direction == TravellerDirection.Backward ? -1 : 1;
+                visualElev *= direction == TravellerDirection.Backward ? -1 : 1;
             }
             else
                 visualElev = 0;

Source/RunActivity/Viewer3D/SuperElevation.cs

@@ -646,9 +646,9 @@ public SuperElevationPrimitive(Viewer viewer, WorldPosition worldPosition,
 
             Matrix PreRotation = Matrix.Identity;
             Elevated = ElevAngles[0];
-            if (Elevated > 0.0f) // Section starts in a curve; first cross section needs to be rotated
+            if (Math.Abs(Elevated) > 0.0f) // Section starts in a curve; first cross section needs to be rotated
             {
-                PreRotation = Matrix.CreateRotationZ(-Elevated * Math.Sign(DTrackData.param1));
+                PreRotation = Matrix.CreateRotationZ(Elevated);
                 PrevRotation = Elevated;
             }
 
@@ -660,7 +660,7 @@ public SuperElevationPrimitive(Viewer viewer, WorldPosition worldPosition,
                 {
                     tmp = new Vector3(v.Position.X, v.Position.Y, v.Position.Z);
 
-                    if (Elevated > 0.0f)
+                    if (Math.Abs(Elevated) > 0.0f)
                     {
                         tmp -= RollOffset;
                         tmp = Vector3.Transform(tmp, PreRotation);
@@ -684,8 +684,6 @@ public SuperElevationPrimitive(Viewer viewer, WorldPosition worldPosition,
                 CurrentRotation = DetermineRotation();
                 Elevated = CurrentRotation - PrevRotation;
                 PrevRotation = CurrentRotation;
-                if (DTrackData.param1 > 0)
-                    Elevated *= -1;
 
                 foreach (Polyline pl in lodItem.Polylines)
                 {
@@ -837,7 +835,7 @@ void CircArcGen()
         public float DetermineRotation()
         {
             float to = (Offset + 1f) / NumSections;
-
+            
             return ElevAngles[to];
         }
     }