Provide default for Ubuntu Focal

CMakeLists.txt

@@ -62,26 +62,52 @@ ign_find_package(sdformat10
 #--------------------------------------
 # Find dartsim for the dartsim plugin wrapper
 
-option(USE_VENDOR_DART "Use internal Open Robotics fork of vendor" BOOL)
+# respect user explicit values and also provide a default value for Ubuntu Focal
+# to make ground vehicles to work properly
+set(DEFAULT_VENDOR_DART:BOOL OFF)
+if(NOT DEFINED USE_VENDOR_DART)
+    if(LSB_RELEASE_EXEC)
+      execute_process(COMMAND ${LSB_RELEASE_EXEC} -rs
+	  OUTPUT_VARIABLE LSB_RELEASE_ID_SHORT
+	  OUTPUT_STRIP_TRAILING_WHITESPACE)
+      if (LSB_RELEASE_ID_SHORT == "20.04")
+        message(STATUS "DETECTED Ubuntu 20.04, default USE_VENDOR_DART set to ON"
+                       "to make ground vehicles to work properly")
+	set(DEFAULT_VENDOR_DART:BOOL ON)
+      endif()
+  endif()
+endif()
+
+option(USE_VENDOR_DART "Use internal Open Robotics fork of DART" ${DEFAULT_VENDOR_DART})
+
+find_program(LSB_RELEASE_EXEC lsb_release)
 if(USE_VENDOR_DART)
     include(ExternalProject)
 
     set(DART_VENDOR_INSTALL_DIR ${CMAKE_BINARY_DIR}/vendor/dart/install)
     set(DART_VENDOR_INCLUDE_DIRS "${DART_VENDOR_INSTALL_DIR}/include")
     set(DART_VENDOR_LIBRARY_DIR "${DART_VENDOR_INSTALL_DIR}/lib")
     # Three libraries needed
-    set(DART_VENDOR_LIBRARY_PATH 
+    set(DART_VENDOR_LIBRARY_PATH
 	"${DART_VENDOR_LIBRARY_DIR}/libdart.so.6.10.0")
+    set(DART_VENDOR_LIBRARY_LINK_PATH
+	"${DART_VENDOR_LIBRARY_DIR}/libdart.so.6.10")
     add_library(dart SHARED IMPORTED)
     set_target_properties(dart PROPERTIES
 	IMPORTED_LOCATION ${DART_VENDOR_LIBRARY_PATH})
+
     set(DART_ODEL_VENDOR_LIBRARY_PATH
 	"${DART_VENDOR_LIBRARY_DIR}/libdart-external-odelcpsolver.so.6.10.0")
+    set(DART_ODEL_VENDOR_LIBRARY_LINK_PATH
+	"${DART_VENDOR_LIBRARY_DIR}/libdart-external-odelcpsolver.so.6.10")
     add_library(dart_external_odelcpsolver SHARED IMPORTED)
     set_target_properties(dart_external_odelcpsolver PROPERTIES
 	IMPORTED_LOCATION ${DART_ODEL_VENDOR_LIBRARY_PATH})
+
     set(DART_COLLISION_VENDOR_LIBRARY_PATH
 	"${DART_VENDOR_LIBRARY_DIR}/libdart-collision-ode.so.6.10.0")
+    set(DART_COLLISION_VENDOR_LIBRARY_LINK_PATH
+	"${DART_VENDOR_LIBRARY_DIR}/libdart-collision-ode.so.6.10")
     add_library(dart_collision_ode SHARED IMPORTED)
     set_target_properties(dart_collision_ode PROPERTIES
 	IMPORTED_LOCATION ${DART_COLLISION_VENDOR_LIBRARY_PATH})