Automatic merge of T1.5.1-1695-gade019506 and 16 pull requests

- Pull request #570 at f4a7495: glTF 2.0 support with PBR lighting
- Pull request #900 at 4629736: DMI in 3D cab + two more dials
- Pull request #1030 at d3ae4a2: Refactor settings, in prep for settings exporter
- Pull request #1045 at cc4d53c: Bugfix: Empty Start Time for Explore, and other issues loading from Menu Selection and Content Routes
- Pull request #1052 at 5bbc476: Content Manager: Add axle count, and lowest derail force
- Pull request #1062 at 3b18c48: Train Forces popup Window.
- Pull request #1064 at 9b3415e: Add Train Info tab to Help window (F1)
- Pull request #1066 at 62c89c1: Log derailment, using TraceInformation.
- Pull request #892 at 1f5ba4c: Signal Function OPP_SIG_ID_TRAINPATH
- Pull request #1000 at d8d9709: Locomotive operation from control car
- Pull request #1029 at 92c74ef: Superelevation Follow Up Fixes
- Pull request #1057 at 50c3789: Switchable brake system
- Pull request #1069 at 3f153f0: Mouse wheel control only with Alt – Followup for #1051
- Pull request #1055 at f6bf9fa: Route Based TTrack Sounds
- Pull request #896 at f1681df: First implementation of https://blueprints.launchpad.net/or/+spec/specific-sounds-for-ai-trains
- Pull request #1049 at 4dd8c4f: Re-organise document storage and access

Author: openrails-bot

Source/RunActivity/Viewer3D/Shapes.cs

@@ -1789,7 +1789,7 @@ public class ShapePrimitive : RenderPrimitive, IDisposable
         protected internal int PrimitiveOffset;
         protected internal PrimitiveType PrimitiveType;
 
-        protected readonly VertexBufferBinding[] VertexBufferBindings;
+        protected internal readonly VertexBufferBinding[] VertexBufferBindings;
 
         public ShapePrimitive() { }
 
@@ -1905,7 +1905,6 @@ public class ShapePrimitiveInstances : RenderPrimitive
         public int SubObjectIndex { get; protected set; }
 
         protected VertexBuffer VertexBuffer;
-        protected VertexDeclaration VertexDeclaration;
         protected int VertexBufferStride;
         protected IndexBuffer IndexBuffer;
         protected int PrimitiveCount;
@@ -1925,7 +1924,6 @@ internal ShapePrimitiveInstances(GraphicsDevice graphicsDevice, ShapePrimitive s
             HierarchyIndex = shapePrimitive.HierarchyIndex;
             SubObjectIndex = subObjectIndex;
             VertexBuffer = shapePrimitive.VertexBuffer;
-            VertexDeclaration = shapePrimitive.VertexBuffer.VertexDeclaration;
             IndexBuffer = shapePrimitive.IndexBuffer;
             PrimitiveCount = shapePrimitive.PrimitiveCount;
             PrimitiveOffset = shapePrimitive.PrimitiveOffset;
@@ -1935,7 +1933,25 @@ internal ShapePrimitiveInstances(GraphicsDevice graphicsDevice, ShapePrimitive s
             InstanceBuffer.SetData(positions);
             InstanceCount = positions.Length;
 
-            VertexBufferBindings = new[] { new VertexBufferBinding(VertexBuffer), new VertexBufferBinding(InstanceBuffer, 0, 1) };
+            var instanceBufferBinding = new VertexBufferBinding(InstanceBuffer, 0, 1);
+
+            if (VertexBuffer != null)
+            {
+                VertexBufferBindings = new[] { new VertexBufferBinding(VertexBuffer), instanceBufferBinding };
+            }
+            else
+            {
+                VertexBufferBindings = shapePrimitive.VertexBufferBindings.ToArray();
+                var dummyInstanceBuffer = RenderPrimitive.GetDummyVertexBuffer(graphicsDevice);
+                var position = -1;
+                for (var i = 0; i < VertexBufferBindings.Length; i++)
+                    if (VertexBufferBindings[i].VertexBuffer == dummyInstanceBuffer)
+                        position = i;
+                if (position == -1)
+                    VertexBufferBindings.Append(instanceBufferBinding);
+                else
+                    VertexBufferBindings[position] = instanceBufferBinding;
+            }
         }
 
         public override void Draw(GraphicsDevice graphicsDevice)