Restores option 02g removed in PR#589

Author: Chris Jakeman

Source/Documentation/Manual/options.rst

@@ -274,16 +274,17 @@ The default setting is checked.
 Viewing distance
 ----------------
 
-This option defines the maximum distance at which terrain is displayed. 
+This option defines the maximum distance at which terrain and objects are displayed. 
 Where the content provides "Distant Mountains", these are displayed independently (see below).
 
-Note: Some routes are optimized for the standard MSTS maximum viewing distance (2km).
-
 Note: When the option to tune settings automatically is applied, then this 
 value will be overridden and dynamically changed to maintain a target frame rate.
 
+Note: Some routes are optimized for a viewing distance of 2km as this is the maximum provided by MSTS.
+
 The default distance is 2km.
 
+
 Distant mountains
 -----------------
 
@@ -293,10 +294,33 @@ Note: "Distant Mountains" are present in the route if it has a folder called LO_
 
 The default setting is checked.
 
-The default distance is 40km
+The default distance is 40km.
 
 .. image:: images/options-mountains.png
 
+
+Extend object maximum viewing distance to horizon
+-------------------------------------------------
+
+With this option selected, all objects viewable up to the viewing distance
+(as defined above) are displayed, even if they have a level of detail (LOD) that is less distant. 
+
+Without this option, ORTS only displays objects up to their peak distance set by their level of detail (LOD) 
+or the viewing distance, whichever is less. 
+
+Selecting this option shows all the objects that should be in view but it may reduce the frame rate.
+MSTS limits the viewing distance to just 2km and the peak LOD distances are usually 2km, so this option
+is especially useful for viewing routes created for MSTS at distances above 2km.
+
+However, for routes that make good use of LOD settings, showing the objects that should be in view can be 
+achieved at higher frame rates by unchecking this option.
+For example, if the viewing distance is 10km and the content has been created with some large objects having 
+peak distance LODs set at 5km and smaller objects having LODs which are much shorter, then this strategy
+will show all the objects that should be in view without reducing the frame rate.
+
+The default setting is checked.
+
+
 Viewing vertical FOV
 --------------------
 

Source/Menu/Options.Designer.cs

@@ -169,6 +169,7 @@ public OptionsForm(UserSettings settings, UpdateManager updateManager, bool init
             labelDistantMountainsViewingDistance.Enabled = checkDistantMountains.Checked;
             numericDistantMountainsViewingDistance.Enabled = checkDistantMountains.Checked;
             numericDistantMountainsViewingDistance.Value = Settings.DistantMountainsViewingDistance / 1000;
+            checkLODViewingExtension.Checked = Settings.LODViewingExtension;
             numericViewingFOV.Value = Settings.ViewingFOV;
             numericWorldObjectDensity.Value = Settings.WorldObjectDensity;
             comboWindowSize.Text = Settings.WindowSize;
@@ -447,6 +448,7 @@ void buttonOK_Click(object sender, EventArgs e)
             Settings.ViewingDistance = (int)numericViewingDistance.Value;
             Settings.DistantMountains = checkDistantMountains.Checked;
             Settings.DistantMountainsViewingDistance = (int)numericDistantMountainsViewingDistance.Value * 1000;
+            Settings.LODViewingExtension = checkLODViewingExtension.Checked;
             Settings.ViewingFOV = (int)numericViewingFOV.Value;
             Settings.WorldObjectDensity = (int)numericWorldObjectDensity.Value;
             Settings.WindowSize = GetValidWindowSize(comboWindowSize.Text);

Source/Menu/Options.cs

@@ -206,6 +206,8 @@ public enum DirectXFeature
         public bool DistantMountains { get; set; }
         [Default(40000)]
         public int DistantMountainsViewingDistance { get; set; }
+        [Default(true)]
+        public bool LODViewingExtension { get; set; }
         [Default(45)] // MSTS uses 60 FOV horizontally, on 4:3 displays this is 45 FOV vertically (what OR uses).
         public int ViewingFOV { get; set; }
         [Default(49)]

Source/ORTS.Settings/UserSettings.cs

@@ -184,11 +184,15 @@ public SharedStaticShapeInstance(Viewer viewer, string path, List<StaticShape> s
                 // Object radius should extend from central location to the furthest instance location PLUS the actual object radius.
                 ObjectRadius = shapes.Max(s => (Location.Location - s.Location.Location).Length()) + dlHighest.ViewSphereRadius;
 
-                // Set to MaxValue so that an object never disappears.
-                // Many MSTS objects had a LOD of 2km which is the maximum distance that MSTS can handle.
-                // Open Rails can handle greater distances, so we override the lowest-detail LOD to make sure OR shows shapes further away than 2km.
-                // See http://www.elvastower.com/forums/index.php?/topic/35301-menu-options/page__view__findpost__p__275531
-                ObjectViewingDistance = float.MaxValue;
+                // Object viewing distance is easy because it's based on the outside of the object radius.
+                if (viewer.Settings.LODViewingExtension)
+                    // Set to MaxValue so that an object never disappears.
+                    // Many MSTS objects had a LOD of 2km which is the maximum distance that MSTS can handle.
+                    // Open Rails can handle greater distances, so we override the lowest-detail LOD to make sure OR shows shapes further away than 2km.
+                    // See http://www.elvastower.com/forums/index.php?/topic/35301-menu-options/page__view__findpost__p__275531
+                    ObjectViewingDistance = float.MaxValue;
+                else
+                    ObjectViewingDistance = dlLowest.ViewingDistance;
             }
 
             // Create all the primitives for the shared shape.
@@ -2522,12 +2526,12 @@ public void PrepareFrame(RenderFrame frame, WorldPosition location, Matrix[] ani
                     ? lodControl.DistanceLevels[lodControl.DistanceLevels.Length - 1]
                     : displayDetail;
 
-                // Extend the lowest LOD to the maximum viewing distance.
-                // Set to MaxValue so that an object never disappears.
-                // Many MSTS objects had a LOD of 2km which is the maximum distance that MSTS can handle.
-                // Open Rails can handle greater distances, so we override the lowest-detail LOD to make sure OR shows shapes further away than 2km.
-                // See http://www.elvastower.com/forums/index.php?/topic/35301-menu-options/page__view__findpost__p__275531
-                if (displayDetailLevel == lodControl.DistanceLevels.Length - 1)
+                // If set, extend the lowest LOD to the maximum viewing distance.
+                if (Viewer.Settings.LODViewingExtension && displayDetailLevel == lodControl.DistanceLevels.Length - 1)
+                    // Set to MaxValue so that an object never disappears.
+                    // Many MSTS objects had a LOD of 2km which is the maximum distance that MSTS can handle.
+                    // Open Rails can handle greater distances, so we override the lowest-detail LOD to make sure OR shows shapes further away than 2km.
+                    // See http://www.elvastower.com/forums/index.php?/topic/35301-menu-options/page__view__findpost__p__275531
                     distanceDetail.ViewingDistance = float.MaxValue;
 
                 for (var i = 0; i < displayDetail.SubObjects.Length; i++)