Bug fix for https://bugs.launchpad.net/or/+bug/1943303 In 3D cabs bars ranging from negative to positive values are incorrectly displayed

Author: Csantucci

Source/RunActivity/Viewer3D/RollingStock/MSTSLocomotiveViewer.cs

@@ -1468,7 +1468,7 @@ public CABViewControlTypes GetControlType()
         /// Gets the requested Locomotive data and returns it as a fraction (from 0 to 1) of the range between Min and Max values.
         /// </summary>
         /// <returns>Data value as fraction (from 0 to 1) of the range between Min and Max values</returns>
-        public float GetRangeFraction()
+        public float GetRangeFraction(bool offsetFromZero = false)
         {
             var data = Locomotive.GetDataOf(Control);
             if (data < Control.MinValue)
@@ -1479,7 +1479,7 @@ public float GetRangeFraction()
             if (Control.MaxValue == Control.MinValue)
                 return 0;
 
-            return (float)((data - Control.MinValue) / (Control.MaxValue - Control.MinValue));
+            return (float)((data - (offsetFromZero && Control.MinValue < 0 ? 0 : Control.MinValue)) / (Control.MaxValue - Control.MinValue));
         }
 
         public CABViewControlStyles GetStyle()
@@ -1630,7 +1630,8 @@ public CabViewGaugeRenderer(Viewer viewer, MSTSLocomotive locomotive, CVCFirebox
 
         public color GetColor(out bool positive)
         {
-            if (Locomotive.GetDataOf(Control) < 0) { positive = false; return Gauge.NegativeColor; }
+            if (Locomotive.GetDataOf(Control) < 0)
+            { positive = false; return Gauge.NegativeColor; }
             else { positive = true; return Gauge.PositiveColor; }
         }
 
@@ -3247,45 +3248,46 @@ public void UpdateDigit()
 
             Material UsedMaterial = FindMaterial();
 
-            float length = CVFR.GetRangeFraction();
+            float length = CVFR.GetRangeFraction(true);
 
             CVCGauge gauge = CVFR.GetGauge();
 
             var len = maxLen * length;
+            var absLen = Math.Abs(len);
             Vertex v1, v2, v3, v4;
 
             //the left-bottom vertex if ori=0;dir=0, right-bottom if ori=0,dir=1; left-top if ori=1,dir=0; left-bottom if ori=1,dir=1;
             v1 = new Vertex(0f, 0f, 0.002f, 0, 0, -1, 0f, 0f);
 
             if (Orientation == 0)
             {
-                if (Direction == 0)//moving right
+                if (Direction == 0 ^ len < 0)//moving right
                 {
                     //other vertices
                     v2 = new Vertex(0f, width, 0.002f, 0, 0, 1, 0f, 0f);
-                    v3 = new Vertex(len, width, 0.002f, 0, 0, 1, 0f, 0f);
-                    v4 = new Vertex(len, 0f, 0.002f, 0, 0, 1, 0f, 0f);
+                    v3 = new Vertex(absLen, width, 0.002f, 0, 0, 1, 0f, 0f);
+                    v4 = new Vertex(absLen, 0f, 0.002f, 0, 0, 1, 0f, 0f);
                 }
                 else //moving left
                 {
                     v4 = new Vertex(0f, width, 0.002f, 0, 0, 1, 0f, 0f);
-                    v3 = new Vertex(-len, width, 0.002f, 0, 0, 1, 0f, 0f);
-                    v2 = new Vertex(-len, 0f, 0.002f, 0, 0, 1, 0f, 0f);
+                    v3 = new Vertex(-absLen, width, 0.002f, 0, 0, 1, 0f, 0f);
+                    v2 = new Vertex(-absLen, 0f, 0.002f, 0, 0, 1, 0f, 0f);
                 }
             }
             else
             {
-                if (Direction == 1)//up
+                if (Direction == 1 ^ len < 0)//up
                 {
                     //other vertices
-                    v2 = new Vertex(0f, len, 0.002f, 0, 0, 1, 0f, 0f);
-                    v3 = new Vertex(width, len, 0.002f, 0, 0, 1, 0f, 0f);
+                    v2 = new Vertex(0f, absLen, 0.002f, 0, 0, 1, 0f, 0f);
+                    v3 = new Vertex(width, absLen, 0.002f, 0, 0, 1, 0f, 0f);
                     v4 = new Vertex(width, 0f, 0.002f, 0, 0, 1, 0f, 0f);
                 }
                 else //moving down
                 {
-                    v4 = new Vertex(0f, -len, 0.002f, 0, 0, 1, 0f, 0f);
-                    v3 = new Vertex(width, -len, 0.002f, 0, 0, 1, 0f, 0f);
+                    v4 = new Vertex(0f, -absLen, 0.002f, 0, 0, 1, 0f, 0f);
+                    v3 = new Vertex(width, -absLen, 0.002f, 0, 0, 1, 0f, 0f);
                     v2 = new Vertex(width, 0, 0.002f, 0, 0, 1, 0f, 0f);
                 }
             }