ENH: allow selective disabling of parallel VTK rendering

- in case an individual geometry element has render issues in parallel

- additional debug information

src/runTimePostProcessing/contourFilter.C

@@ -183,6 +183,12 @@ addGeometry
     colourFieldInfo.reduce();
 
 
+    DebugInfo
+        << "    Field " << fieldName_ << ' ' << fieldInfo.info() << nl
+        << "    Field " << colourFieldName_ << ' ' << colourFieldInfo.info()
+        << endl;
+
+
     // Not rendered on this processor?
     // This is where we stop, but could also have an MPI barrier
     if (!renderer)

src/runTimePostProcessing/functionObjectCloud.C

@@ -153,8 +153,7 @@ addGeometryFromFile
             else
             {
                 DebugInfo
-                    << "    Resolved cloud file "
-                    << inputFileName_ << endl;
+                    << "    Resolved cloud file " << inputFileName_ << endl;
             }
         }
         else
@@ -198,6 +197,12 @@ addGeometryFromFile
         fieldSummary colourFieldInfo =
             queryFieldSummary(colourFieldName_, polyData);
 
+        DebugInfo
+            << "    Field " << fieldName_ << ' ' << scaleFieldInfo.info() << nl
+            << "    Field " << colourFieldName_ << ' ' << colourFieldInfo.info()
+            << endl;
+
+
         // No reduction
 
         auto mapper = vtkSmartPointer<vtkPolyDataMapper>::New();

src/runTimePostProcessing/functionObjectSurface.C

@@ -129,7 +129,8 @@ addGeometry
         return false;
     }
 
-    DebugInfo << "    Resolve surface " << functionObjectName_ << endl;
+    DebugInfo
+        << "    Find surface " << functionObjectName_ << endl;
 
     const polySurface* surf =
     (
@@ -181,12 +182,11 @@ addGeometry
             << functionObjectName_
             << endl;
 
-        if (debug)
-        {
-            Info<< "    Available surfaces:" << nl
-                << geometryBase::parent_.storedObjects()
-                    .sortedNames<polySurface>() << endl;
-        }
+        DebugInfo
+            << "    Available surfaces:" << nl
+            << geometryBase::parent_.storedObjects()
+                .sortedNames<polySurface>() << endl;
+
         return false;
     }
 
@@ -252,6 +252,9 @@ addGeometry
     fieldSummary fieldInfo = queryFieldSummary(fieldName_, multiPiece);
     fieldInfo.reduce();
 
+    DebugInfo
+        << "    Field " << fieldName_ << ' ' << fieldInfo.info() << endl;
+
 
     // Not rendered on this processor?
     // This is where we stop, but could also have an MPI barrier
@@ -370,7 +373,8 @@ addGeometryFromFile
             }
             else
             {
-                DebugInfo << "    Resolved surface " << fName << endl;
+                DebugInfo
+                    << "    Resolved surface " << fName << endl;
             }
         }
         else
@@ -401,6 +405,9 @@ addGeometryFromFile
     fieldSummary fieldInfo = queryFieldSummary(fieldName_, polyData);
     // No reduction (serial)
 
+    DebugInfo
+        << "    Field " << fieldName_ << ' ' << fieldInfo.info() << endl;
+
 
     // Render
 
@@ -472,7 +479,8 @@ addGeometryToScene
     }
     else
     {
-        DebugInfo << "Using file source only" << nl;
+        DebugInfo
+            << "Using file source only" << nl;
     }
 
     // File source

src/runTimePostProcessing/geometryBase.C

@@ -39,7 +39,6 @@ namespace functionObjects
 {
 namespace runTimePostPro
 {
-
     defineDebugSwitchWithName(geometryBase, "runTimePostPro::geometryBase", 0);
 }
 }
@@ -100,6 +99,16 @@ Foam::functionObjects::runTimePostPro::geometryBase::geometryBase
     parent_(parent),
     name_(dict.dictName()),
     visible_(dict.getOrDefault("visible", true)),
+    parallel_
+    (
+        // User input can only disable parallel here
+        #ifdef FOAM_USING_VTK_MPI
+        Pstream::parRun() && parent.parallel()
+     && dict.getOrDefault("parallel", parent.parallel())
+        #else
+        false
+        #endif
+    ),
     renderMode_
     (
         renderModeTypeNames.getOrDefault("renderMode", dict, rmGouraud)
@@ -136,7 +145,7 @@ Foam::functionObjects::runTimePostPro::geometryBase::parent() const
 bool Foam::functionObjects::runTimePostPro::geometryBase::
 needsCollective() const
 {
-    return parent_.needsCollective();
+    return Pstream::parRun() && (!parent_.parallel() || !parallel_);
 }
 
 
@@ -147,12 +156,6 @@ Foam::functionObjects::runTimePostPro::geometryBase::name() const
 }
 
 
-bool Foam::functionObjects::runTimePostPro::geometryBase::visible() const
-{
-    return visible_;
-}
-
-
 Foam::scalar Foam::functionObjects::runTimePostPro::geometryBase::opacity
 (
     const scalar position

src/runTimePostProcessing/geometryBase.H

@@ -29,10 +29,11 @@ Description
 
     Dictionary controls
     \table
-        Property    | Description                          | Required | Default
-        visible     | Display the object                   | no  | yes
-        renderMode  | Shading (flat/gouraud/phong)         | no  | gouraud
-        opacity     | Object opacity                       | no  | 1.0
+        Property    | Description                           | Required | Default
+        visible     | Display the object                    | no  | yes
+        renderMode  | Shading (flat/gouraud/phong)          | no  | gouraud
+        opacity     | Object opacity                        | no  | 1.0
+        parallel    | Allow parallel rendering              | no  | true
     \endtable
 
 SourceFiles
@@ -102,6 +103,9 @@ protected:
         //- Visible flag
         bool visible_;
 
+        //- Allow parallel rendering
+        bool parallel_;
+
         //- Render mode
         renderModeType renderMode_;
 
@@ -146,8 +150,6 @@ public:
 
     // Member Functions
 
-    // Access
-
         //- Return the reference to the parent function object
         const runTimePostProcessing& parent() const;
 
@@ -159,7 +161,16 @@ public:
         const word& name() const;
 
         //- Return the visible flag
-        bool visible() const;
+        bool visible() const
+        {
+            return visible_;
+        }
+
+        //- Allow parallel rendering
+        bool parallel() const
+        {
+            return parallel_;
+        }
 
         //- Return the opacity
         scalar opacity(const scalar position) const;

src/runTimePostProcessing/geometryCloud.C

@@ -183,6 +183,9 @@ addGeometry
         return true;
     }
 
+    DebugInfo
+        << "    Render cloud " << cloudName_ << endl;
+
 
     // Rendering
 

src/runTimePostProcessing/geometryPatches.C

@@ -204,6 +204,8 @@ void Foam::functionObjects::runTimePostPro::geometryPatches::addGeometryToScene
     fieldSummary fieldInfo = queryFieldSummary(fieldName_, multiPiece);
     fieldInfo.reduce();
 
+    DebugInfo
+        << "    Field " << fieldName_ << ' ' << fieldInfo.info() << endl;
 
     // Not rendering on this processor?
     // This is where we stop, but could also have a MPI barrier

src/runTimePostProcessing/runTimePostProcessing.C

@@ -85,7 +85,14 @@ static void addGeometryToScene
 {
     for (Type& obj : objects)
     {
-        obj.addGeometryToScene(position, renderer);
+        if (Pstream::master() || obj.parallel())
+        {
+            obj.addGeometryToScene(position, renderer);
+        }
+        else
+        {
+            obj.addGeometryToScene(position, nullptr);
+        }
     }
 }
 

src/runTimePostProcessing/runTimePostProcessing.H

@@ -97,10 +97,10 @@ Description
 
     Dictionary controls
     \table
-        Property    | Description                          | Required | Default
-        type        | Type-name: runTimePostProcessing     | yes |
-        debug       | Additional debug information         | no  | false
-        parallel    | Enable/disable VTK parallel          | no  | true
+        Property    | Description                           | Required | Default
+        type        | Type-name: runTimePostProcessing      | yes |
+        debug       | Additional debug information          | no  | false
+        parallel    | Allow parallel rendering              | no  | true
     \endtable
 
 SourceFiles
@@ -163,7 +163,7 @@ class runTimePostProcessing
         //- Output instance
         outputType output_;
 
-        //- Parallel rendering
+        //- Allow parallel rendering
         bool parallel_;
 
         //- Scene manager
@@ -221,7 +221,7 @@ public:
 
     // Member Functions
 
-        //- Parallel rendering
+        //- Allow parallel rendering
         bool parallel() const
         {
             return parallel_;