Automatic merge of T1.5.1-376-g885592329 and 12 pull requests

- Pull request #570 at de7a14f: Experimental glTF 2.0 support with PBR lighting
- Pull request #732 at 2451991: Improvements for air brakes
- Pull request #751 at 00981a2: Web interface to control cab controls with external hardware
- Pull request #799 at dc03850: Consolidated wind simulation
- Pull request #802 at 4d198e4: Added support for activity location events to the TrackViewer
- Pull request #803 at 7157e08: Various adjustments to steam adhesion
- Pull request #813 at 8223595: Refactored garbage generators
- Pull request #815 at a5cc165: chore: Add GitHub automatic release notes configuration
- Pull request #818 at 73b637f: Allow independent drive axles for locomotives
- Pull request #820 at 6e7a5b6: delay option for masterkey does not delay switch off
- Pull request #821 at e0fa5a8: Adds suppression of safety valves
- Pull request #822 at 82ef736: battery switch two buttons option in combination with a delay

Author: openrails-bot

Source/ORTS.Common/Filter.cs

@@ -50,8 +50,8 @@ public class IIRFilter
         int NCoef;
         List<float> ACoef;
         List<float> BCoef;
-        List<float> y;
-        List<float> x;
+        float[] x;
+        float[] y;
 
         public IIRFilter()
         {
@@ -94,8 +94,8 @@ Z domain Poles
 
             NCoef = A.Count - 1;
 
-            x = Enumerable.Repeat(0f, NCoef).ToList();
-            y = Enumerable.Repeat(0f, NCoef).ToList();
+            x = new float[NCoef + 1];
+            y = new float[NCoef + 1];
 
             FilterType = FilterTypes.Bessel;
         }
@@ -112,8 +112,8 @@ public IIRFilter(List<float> a, List<float> b, FilterTypes type)
             NCoef = a.Count - 1;
             ACoef = a;
             BCoef = b;
-            x = Enumerable.Repeat(0f, NCoef).ToList();
-            y = Enumerable.Repeat(0f, NCoef).ToList();
+            x = new float[NCoef + 1];
+            y = new float[NCoef + 1];
         }
 
         /// <summary>
@@ -145,8 +145,8 @@ public IIRFilter(FilterTypes type, int order, float cutoffFrequency, float sampl
             NCoef = A.Count - 1;
             ACoef = A;
             BCoef = B;
-            x = Enumerable.Repeat(0f, NCoef).ToList();
-            y = Enumerable.Repeat(0f, NCoef).ToList();
+            x = new float[NCoef + 1];
+            y = new float[NCoef + 1];
         }
 
         /// <summary>
@@ -158,8 +158,8 @@ public List<float> A
             {
                 if (NCoef <= 0)
                     NCoef = value.Count - 1;
-                x = Enumerable.Repeat(0f, NCoef).ToList();
-                y = Enumerable.Repeat(0f, NCoef).ToList();
+                x = new float[NCoef + 1];
+                y = new float[NCoef + 1];
                 if (ACoef == null)
                     ACoef = new List<float>();
                 ACoef.Clear();
@@ -183,8 +183,8 @@ public List<float> B
             {
                 if (NCoef <= 0)
                     NCoef = value.Count - 1;
-                x = Enumerable.Repeat(0f, NCoef).ToList();
-                y = Enumerable.Repeat(0f, NCoef).ToList();
+                x = new float[NCoef + 1];
+                y = new float[NCoef + 1];
                 if (BCoef == null)
                     BCoef = new List<float>();
                 BCoef.Clear();
@@ -257,9 +257,15 @@ public enum FilterTypes
         /// <returns>Filtered value</returns>
         public float Filter(float NewSample)
         {
+            //shift the old samples
+            for (int n = x.Length - 1; n > 0; n--)
+            {
+                x[n] = x[n - 1];
+                y[n] = y[n - 1];
+            }
             //Calculate the new output
-            x.Insert(0, NewSample);
-            y.Insert(0, ACoef[0] * x[0]);
+            x[0] = NewSample;
+            y[0] = ACoef[0] * x[0];
             for (int n = 1; n <= NCoef; n++)
                 y[0] += ACoef[n] * x[n] - BCoef[n] * y[n];
 
@@ -291,8 +297,15 @@ public float Filter(float NewSample, float samplingPeriod)
                 default:
                     throw new NotImplementedException("Other filter types are not implemented yet. Try to use constant sampling period and Filter(float NewSample) version of this method.");
             }
-            x.Insert(0, NewSample);
-            y.Insert(0, ACoef[0] * x[0]);
+            //shift the old samples
+            for (int n = x.Length - 1; n > 0; n--)
+            {
+                x[n] = x[n - 1];
+                y[n] = y[n - 1];
+            }
+            //Calculate the new output
+            x[0] = NewSample;
+            y[0] = ACoef[0] * x[0];
             for (int n = 1; n <= NCoef; n++)
                 y[0] += ACoef[n] * x[n] - BCoef[n] * y[n];
 
@@ -304,11 +317,8 @@ public float Filter(float NewSample, float samplingPeriod)
         /// </summary>
         public void Reset()
         {
-            for (int i = 0; i < x.Count; i++)
-            {
-                x[i] = 0.0f;
-                y[i] = 0.0f;
-            }
+            Array.Clear(x);
+            Array.Clear(y);
         }
         /// <summary>
         /// Resets all buffers of the filter with given initial value