CONFIG: prefer use of ParaView_MESA_DIR in runTimePostProcessing

- when using VTK from ParaView sources it can better to tag them as
  such, but simultaneously not mask the ParaView with hardware
  rendering.

  The additional ParaView_MESA_DIR variable allows this.
  The balance of library and path setup is unaffected by this.

DOC: update doc/BuildIssues

doc/BuildIssues.md

@@ -1,3 +1,33 @@
+## Known Build Issues (OpenFOAM-v1912)
+
+### ParaView, ParaView-Catalyst
+
+ParaView v5.7.0 received an extensive reworking of its CMake setup,
+including a complete change in its macros for building external
+plugins.
+
+- We can currently build the reader plugins for this new 5.7.0 system,
+  but the installation is not as smooth as it should be.
+
+These CMake changes also affect our ability to build with Catalyst.
+This is independent of the removal of Catalyst _editions_
+(to be reintroduced in 5.8.0).
+
+- The builds with the Catalyst function-object with 5.7.0 are even
+  more of a _work-in-progress_ at this stage as we cope with the new
+  CMake system.
+
+We thus currently do not build with ParaView-5.7. If building plugins or with
+Catalyst, please use the latest ParaView-5.6 version instead for now.
+Or simply use ParaView with the regular, builtin VTK readers.
+
+### Windows cross-compilation
+
+The reacting Euler multiphase solvers currently do not build for
+Windows. Compile with the `-k` option to skip over these applications
+for now.
+
+
 ## Known Build Issues (OpenFOAM-v1906)
 
 ### Thermo problems with Clang

etc/config.csh/unset

@@ -31,10 +31,13 @@ endif
 # The old dirs to be cleaned from the environment variables
 set foamOldDirs="$WM_PROJECT_DIR $WM_THIRD_PARTY_DIR $HOME/$WM_PROJECT/$LOGNAME $FOAM_SITE_APPBIN $FOAM_SITE_LIBBIN"
 if ( $?WM_PROJECT_SITE ) then
-   set foamOldDirs="$foamOldDirs $WM_PROJECT_SITE"
+    set foamOldDirs="$foamOldDirs $WM_PROJECT_SITE"
 endif
 if ( $?ParaView_DIR ) then
-   set foamOldDirs="$foamOldDirs $ParaView_DIR"
+    set foamOldDirs="$foamOldDirs $ParaView_DIR"
+endif
+if ( $?ParaView_MESA_DIR ) then
+    set foamOldDirs="$foamOldDirs $ParaView_MESA_DIR"
 endif
 
 
@@ -109,10 +112,10 @@ unsetenv OPAL_PREFIX
 
 
 #------------------------------------------------------------------------------
-# Unset Ensight/ParaView-related environment variables
+# Unset ParaView/VTK-related environment variables
 
-unsetenv ENSIGHT9_READER
 unsetenv ParaView_DIR
+unsetenv ParaView_MESA_DIR
 unsetenv ParaView_INCLUDE_DIR
 unsetenv ParaView_VERSION
 unsetenv PV_PLUGIN_PATH

etc/config.csh/vtk

@@ -25,7 +25,8 @@
 #     Changes made here MUST be made in the equivalent config.sh version too,
 #     since that is the one used in the build process.
 #
-# It is recommended to use VTK sources from ParaView (5.0.1 or later)
+# It is recommended to use VTK sources from ParaView (5.0.1 or later).
+# When doing so, the ParaView_MESA_DIR variable can be set accordingly.
 #
 # See doc/BuildIssues.md about problems that can be encountered when using
 # the 'plain' VTK sources.
@@ -40,6 +41,9 @@ setenv VTK_DIR "$WM_THIRD_PARTY_DIR/platforms/$WM_ARCH$WM_COMPILER/$vtk_version"
 setenv MESA_ARCH_PATH "$WM_THIRD_PARTY_DIR/platforms/$WM_ARCH$WM_COMPILER/$mesa_version"
 setenv LLVM_ARCH_PATH "$WM_THIRD_PARTY_DIR/platforms/$WM_ARCH/$mesa_llvm"
 
+# Define paraview-mesa directory as required
+unsetenv ParaView_MESA_DIR
+
 # END OF (NORMAL) USER EDITABLE PART
 #------------------------------------------------------------------------------
 if ($?FOAM_VERBOSE && $?prompt) then

etc/config.sh/unset

@@ -27,7 +27,8 @@ foamClean=$WM_PROJECT_DIR/bin/foamCleanPath
 # The old dirs to be cleaned from the environment variables
 foamOldDirs="$WM_PROJECT_DIR $WM_THIRD_PARTY_DIR \
     $HOME/$WM_PROJECT/$USER $FOAM_USER_APPBIN $FOAM_USER_LIBBIN \
-    $WM_PROJECT_SITE $FOAM_SITE_APPBIN $FOAM_SITE_LIBBIN $ParaView_DIR"
+    $WM_PROJECT_SITE $FOAM_SITE_APPBIN $FOAM_SITE_LIBBIN \
+    $ParaView_DIR $ParaView_MESA_DIR"
 
 #------------------------------------------------------------------------------
 # Unset WM_* environment variables
@@ -103,10 +104,10 @@ then
 fi
 
 #------------------------------------------------------------------------------
-# Unset Ensight/ParaView-related environment variables
+# Unset ParaView/VTK-related environment variables
 
-unset ENSIGHT9_READER
 unset ParaView_DIR
+unset ParaView_MESA_DIR
 unset ParaView_INCLUDE_DIR
 unset ParaView_VERSION
 unset PV_PLUGIN_PATH

etc/config.sh/vtk

@@ -26,7 +26,8 @@
 #       - vtk_version, mesa_version variables are retained.
 #         (for future integration into ThirdParty build)
 #
-# It is recommended to use VTK sources from ParaView (5.0.1 or later)
+# It is recommended to use VTK sources from ParaView (5.0.1 or later).
+# When doing so, the ParaView_MESA_DIR variable can be set accordingly.
 #
 # See doc/BuildIssues.md about problems that can be encountered when using
 # the 'plain' VTK sources.
@@ -41,6 +42,9 @@ export VTK_DIR="$WM_THIRD_PARTY_DIR/platforms/$WM_ARCH$WM_COMPILER/$vtk_version"
 export MESA_ARCH_PATH="$WM_THIRD_PARTY_DIR/platforms/$WM_ARCH$WM_COMPILER/$mesa_version"
 export LLVM_ARCH_PATH="$WM_THIRD_PARTY_DIR/platforms/$WM_ARCH/$mesa_llvm"
 
+# Define paraview-mesa directory as required
+unset ParaView_MESA_DIR
+
 # END OF (NORMAL) USER EDITABLE PART
 #------------------------------------------------------------------------------
 if [ -n "$FOAM_VERBOSE" ] && [ -n "$PS1" ]
@@ -49,6 +53,10 @@ then
     echo "    vtk  ($vtk_version) $VTK_DIR" 1>&2
     echo "    mesa ($mesa_version) $MESA_ARCH_PATH" 1>&2
     echo "    llvm ($mesa_llvm) $LLVM_ARCH_PATH" 1>&2
+    if [ -d "$ParaView_MESA_DIR" ]
+    then
+    echo "    paraview-mesa $ParaView_MESA_DIR" 1>&2
+    fi
 fi
 
 if command -v _foamAddLib >/dev/null  # normal sourcing

src/functionObjects/graphics/runTimePostProcessing/Allwmake

@@ -8,6 +8,12 @@ echo "${PWD##*/} : $PWD"
 
 unset depend runTimePostProDebug
 
+# If available, prefer use of ParaView MESA
+if [ -d "$ParaView_MESA_DIR" ]
+then
+    export ParaView_DIR="$ParaView_MESA_DIR"
+fi
+
 if [ -d "$VTK_DIR" ]
 then
     depend="VTK_DIR=$VTK_DIR"