Convert terrasync into a subsystem.

Fixed scenery tile refresh method.
Simgear automake makefiles with libsvn detection.
Simgear CMake support for libsvn (may not work :) )

simgear/scene/CMakeLists.txt

@@ -9,6 +9,7 @@ foreach( mylibfolder
         sky
         tgdb
         util
+        tsync
     )
 
     add_subdirectory(${mylibfolder})

simgear/scene/tgdb/TileCache.cxx

@@ -192,13 +192,8 @@ void TileCache::refresh_tile(long tile_index)
 
     SG_LOG( SG_TERRAIN, SG_DEBUG, "REFRESHING CACHE ENTRY = " << tile_index );
 
-    TileEntry* e = NULL;
-    if (!it->second->is_expired(current_time))
-        e = new TileEntry(it->second);
-
-    entry_free(tile_index);
-    if (e)
-        tile_cache[tile_index] = e;
+    if (it->second)
+        it->second->refresh();
 }
 
 // update tile's priority and expiry time according to current request
@@ -207,7 +202,7 @@ void TileCache::request_tile(TileEntry* t,float priority,bool current_view,doubl
     if ((!current_view)&&(request_time<=0.0))
         return;
 
-    // update priority when hire - or old has expired
+    // update priority when higher - or old request has expired
     if ((t->is_expired(current_time))||
          (priority > t->get_priority()))
     {

simgear/scene/tgdb/TileEntry.cxx

@@ -415,3 +415,20 @@ TileEntry::removeFromSceneGraph()
         }
     }
 }
+
+void
+TileEntry::refresh()
+{
+    osg::Group *parent = NULL;
+    // find the nodes branch parent
+    if ( _node->getNumParents() > 0 ) {
+        // find the first parent (should only be one)
+        parent = _node->getParent( 0 ) ;
+        if( parent ) {
+            parent->removeChild( _node.get() );
+        }
+    }
+    _node = new osg::LOD;
+    if (parent)
+        parent->addChild(_node.get());
+}

simgear/scene/tgdb/TileEntry.hxx

@@ -131,8 +131,12 @@ public:
      * graph for this tile.
      */
     void removeFromSceneGraph();
+    
+    /**
+     * Refresh a tile, reload the node from disk.
+     */
+    void refresh();
 
-	
     /**
      * return the scenegraph node for the terrain
      */

simgear/scene/tsync/CMakeLists.txt

@@ -0,0 +1,11 @@
+include (SimGearComponent)
+
+set(HEADERS
+    terrasync.hxx
+    )
+
+set(SOURCES 
+    terrasync.cxx
+    )
+
+simgear_component(tsync scene/tsync "${SOURCES}" "${HEADERS}")

simgear/scene/tsync/Makefile.am

@@ -0,0 +1,15 @@
+includedir = @includedir@/scene/tsync
+
+AM_CPPFLAGS = $(svn_CPPFLAGS)
+
+lib_LIBRARIES = libsgtsync.a
+
+noinst_HEADERS =
+
+include_HEADERS = \
+	terrasync.hxx
+
+libsgtsync_a_SOURCES = \
+	terrasync.cxx
+
+INCLUDES = -I$(top_srcdir)