X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FScenery%2Ftilemgr.cxx;h=298b05c50d20bcf5a081ce1356cef564f1f14248;hb=948aa70af78626584042b70fdf3c3babfb5aa804;hp=e5cd08bbb281bd8b9358b71f0cd468d831bbde06;hpb=9604908a8d38767345410447b75a13582158128e;p=flightgear.git

diff --git a/src/Scenery/tilemgr.cxx b/src/Scenery/tilemgr.cxx
index e5cd08bbb..298b05c50 100644
--- a/src/Scenery/tilemgr.cxx
+++ b/src/Scenery/tilemgr.cxx
@@ -29,116 +29,155 @@
 #include <functional>
 
 #include <osgViewer/Viewer>
+#include <osgDB/Registry>
 
 #include <simgear/constants.h>
 #include <simgear/debug/logstream.hxx>
 #include <simgear/structure/exception.hxx>
 #include <simgear/scene/model/modellib.hxx>
-#include <simgear/scene/tgdb/SGReaderWriterBTGOptions.hxx>
+#include <simgear/scene/util/SGReaderWriterOptions.hxx>
+#include <simgear/scene/tsync/terrasync.hxx>
 
 #include <Main/globals.hxx>
 #include <Main/fg_props.hxx>
-#include <Main/renderer.hxx>
-#include <Main/viewer.hxx>
+#include <Viewer/renderer.hxx>
+#include <Viewer/splash.hxx>
 #include <Scripting/NasalSys.hxx>
+#include <Scripting/NasalModelData.hxx>
 
 #include "scenery.hxx"
 #include "SceneryPager.hxx"
 #include "tilemgr.hxx"
 
-using std::for_each;
 using flightgear::SceneryPager;
-using simgear::SGModelLib;
-using simgear::TileEntry;
-using simgear::TileCache;
+
 
 FGTileMgr::FGTileMgr():
     state( Start ),
-    vis( 16000 )
+    last_state( Running ),
+    longitude(-1000.0),
+    latitude(-1000.0),
+    scheduled_visibility(100.0),
+    _terra_sync(NULL),
+    _visibilityMeters(fgGetNode("/environment/visibility-m", true)),
+    _maxTileRangeM(fgGetNode("/sim/rendering/static-lod/bare", true)),
+    _disableNasalHooks(fgGetNode("/sim/temp/disable-scenery-nasal", true)),
+    _scenery_loaded(fgGetNode("/sim/sceneryloaded", true)),
+    _scenery_override(fgGetNode("/sim/sceneryloaded-override", true)),
+    _pager(FGScenery::getPagerSingleton())
 {
 }
 
 
-FGTileMgr::~FGTileMgr() {
+FGTileMgr::~FGTileMgr()
+{
     // remove all nodes we might have left behind
     osg::Group* group = globals->get_scenery()->get_terrain_branch();
     group->removeChildren(0, group->getNumChildren());
+    // clear OSG cache
+    osgDB::Registry::instance()->clearObjectCache();
 }
 
 
 // Initialize the Tile Manager subsystem
-int FGTileMgr::init() {
+void FGTileMgr::init() {
     SG_LOG( SG_TERRAIN, SG_INFO, "Initializing Tile Manager subsystem." );
 
-    _options = new SGReaderWriterBTGOptions;
-    _options->setMatlib(globals->get_matlib());
-    _options->setUseRandomObjects(fgGetBool("/sim/rendering/random-objects", true));
-    _options->setUseRandomVegetation(fgGetBool("/sim/rendering/random-vegetation", true));
+    _options = new simgear::SGReaderWriterOptions;
+    _options->setMaterialLib(globals->get_matlib());
+    _options->setPropertyNode(globals->get_props());
+
     osgDB::FilePathList &fp = _options->getDatabasePathList();
     const string_list &sc = globals->get_fg_scenery();
     fp.clear();
     std::copy(sc.begin(), sc.end(), back_inserter(fp));
+    _options->setPluginStringData("SimGear::FG_ROOT", globals->get_fg_root());
+    if (!_disableNasalHooks->getBoolValue())
+        _options->setModelData(new FGNasalModelDataProxy);
 
-    TileEntry::setModelLoadHelper(this);
+    reinit();
+}
 
-    tile_cache.init();
+void FGTileMgr::refresh_tile(void* tileMgr, long tileIndex)
+{
+    ((FGTileMgr*) tileMgr)->tile_cache.refresh_tile(tileIndex);
+}
 
+void FGTileMgr::reinit()
+{
+    _terra_sync = static_cast<simgear::SGTerraSync*> (globals->get_subsystem("terrasync"));
+    if (_terra_sync)
+        _terra_sync->setTileRefreshCb(&refresh_tile, this);
+
+    // protect against multiple scenery reloads and properly reset flags,
+    // otherwise aircraft fall through the ground while reloading scenery
+    if (!fgGetBool("/sim/sceneryloaded",true))
+        return;
+    fgSetBool("/sim/sceneryloaded",false);
+    fgSetDouble("/sim/startup/splash-alpha", 1.0);
+    
+    // Reload the materials definitions
+    _options->setMaterialLib(globals->get_matlib());
+
+    // remove all old scenery nodes from scenegraph and clear cache
+    osg::Group* group = globals->get_scenery()->get_terrain_branch();
+    group->removeChildren(0, group->getNumChildren());
+    tile_cache.init();
+    
+    // clear OSG cache, except on initial start-up
+    if (state != Start)
+    {
+        osgDB::Registry::instance()->clearObjectCache();
+    }
+    
     state = Inited;
-
+    
     previous_bucket.make_bad();
     current_bucket.make_bad();
-
     longitude = latitude = -1000.0;
+    scheduled_visibility = 100.0;
 
-    return 1;
+    // force an update now
+    update(0.0);
 }
 
-// schedule a tile for loading
-void FGTileMgr::sched_tile( const SGBucket& b, const bool is_inner_ring ) {
+/* schedule a tile for loading, keep request for given amount of time.
+ * Returns true if tile is already loaded. */
+bool FGTileMgr::sched_tile( const SGBucket& b, double priority, bool current_view, double duration)
+{
     // see if tile already exists in the cache
     TileEntry *t = tile_cache.get_tile( b );
-
-    if ( !t ) {
-        // make space in the cache
-        SceneryPager* pager = FGScenery::getPagerSingleton();
-        while ( (int)tile_cache.get_size() > tile_cache.get_max_cache_size() ) {
-            long index = tile_cache.get_oldest_tile();
-            if ( index >= 0 ) {
-                TileEntry *old = tile_cache.get_tile( index );
-                tile_cache.clear_entry( index );
-                osg::ref_ptr<osg::Object> subgraph = old->getNode();
-                old->removeFromSceneGraph();
-                delete old;
-                // zeros out subgraph ref_ptr, so subgraph is owned by
-                // the pager and will be deleted in the pager thread.
-                pager->queueDeleteRequest(subgraph);
-            } else {
-                // nothing to free ?!? forge ahead
-                break;
-            }
-        }
-
+    if (!t)
+    {
         // create a new entry
-        TileEntry *e = new TileEntry( b );
-
-        // insert the tile into the cache
-        if ( tile_cache.insert_tile( e ) ) {
-            // update_queues will generate load request
-        } else {
+        t = new TileEntry( b );
+        // insert the tile into the cache, update will generate load request
+        if ( tile_cache.insert_tile( t ) )
+        {
+            // Attach to scene graph
+
+            t->addToSceneGraph(globals->get_scenery()->get_terrain_branch());
+        } else
+        {
             // insert failed (cache full with no available entries to
             // delete.)  Try again later
-            delete e;
+            delete t;
+            return false;
         }
-        // Attach to scene graph
-        e->addToSceneGraph(globals->get_scenery()->get_terrain_branch());
-    } else {
-        t->set_inner_ring( is_inner_ring );
+
+        SG_LOG( SG_TERRAIN, SG_DEBUG, "  New tile cache size " << (int)tile_cache.get_size() );
     }
-}
 
+    // update tile's properties
+    tile_cache.request_tile(t,priority,current_view,duration);
+
+    return t->is_loaded();
+}
 
-// schedule a needed buckets for loading
-void FGTileMgr::schedule_needed( double vis, const SGBucket& curr_bucket) {
+/* schedule needed buckets for the current view position for loading,
+ * keep request for given amount of time */
+void FGTileMgr::schedule_needed(const SGBucket& curr_bucket, double vis)
+{
     // sanity check (unfortunately needed!)
     if ( longitude < -180.0 || longitude > 180.0 
          || latitude < -90.0 || latitude > 90.0 )
@@ -146,24 +185,20 @@ void FGTileMgr::schedule_needed( double vis, const SGBucket& curr_bucket) {
         SG_LOG( SG_TERRAIN, SG_ALERT,
                 "Attempting to schedule tiles for bogus lon and lat  = ("
                 << longitude << "," << latitude << ")" );
-        return;		// FIXME
-        SG_LOG( SG_TERRAIN, SG_ALERT,
-                "This is a FATAL error.  Exiting!" );
-        exit(-1);
+        return;
     }
 
     SG_LOG( SG_TERRAIN, SG_INFO,
             "scheduling needed tiles for " << longitude << " " << latitude );
 
-    // vis = fgGetDouble("/environment/visibility-m");
-
     double tile_width = curr_bucket.get_width_m();
     double tile_height = curr_bucket.get_height_m();
     // cout << "tile width = " << tile_width << "  tile_height = "
     //      << tile_height << endl;
 
-    xrange = (int)(vis / tile_width) + 1;
-    yrange = (int)(vis / tile_height) + 1;
+    double tileRangeM = std::min(vis,_maxTileRangeM->getDoubleValue());
+    int xrange = (int)(tileRangeM / tile_width) + 1;
+    int yrange = (int)(tileRangeM / tile_height) + 1;
     if ( xrange < 1 ) { xrange = 1; }
     if ( yrange < 1 ) { yrange = 1; }
 
@@ -174,283 +209,252 @@ void FGTileMgr::schedule_needed( double vis, const SGBucket& curr_bucket) {
     // cout << "max cache size = " << tile_cache.get_max_cache_size()
     //      << " current cache size = " << tile_cache.get_size() << endl;
 
-    // clear the inner ring flags so we can set them below.  This
-    // prevents us from having "true" entries we aren't able to find
-    // to get rid of if we teleport a long ways away from the current
-    // location.
-    tile_cache.clear_inner_ring_flags();
+    // clear flags of all tiles belonging to the previous view set 
+    tile_cache.clear_current_view();
 
-    SGBucket b;
+    // update timestamps, so all tiles scheduled now are *newer* than any tile previously loaded
+    osg::FrameStamp* framestamp
+            = globals->get_renderer()->getViewer()->getFrameStamp();
+    tile_cache.set_current_time(framestamp->getReferenceTime());
 
-    // schedule center tile first so it can be loaded first
-    b = sgBucketOffset( longitude, latitude, 0, 0 );
-    sched_tile( b, true );
+    SGBucket b;
 
     int x, y;
 
-    // schedule next ring of 8 tiles
-    for ( x = -1; x <= 1; ++x ) {
-        for ( y = -1; y <= 1; ++y ) {
-            if ( x != 0 || y != 0 ) {
-                b = sgBucketOffset( longitude, latitude, x, y );
-                sched_tile( b, true );
-            }
-        }
-    }
-
-    // schedule remaining tiles
-    for ( x = -xrange; x <= xrange; ++x ) {
-        for ( y = -yrange; y <= yrange; ++y ) {
-            if ( x < -1 || x > 1 || y < -1 || y > 1 ) {
-                SGBucket b = sgBucketOffset( longitude, latitude, x, y );
-                sched_tile( b, false );
-            }
+    /* schedule all tiles, use distance-based loading priority,
+     * so tiles are loaded in innermost-to-outermost sequence. */
+    for ( x = -xrange; x <= xrange; ++x )
+    {
+        for ( y = -yrange; y <= yrange; ++y )
+        {
+            SGBucket b = sgBucketOffset( longitude, latitude, x, y );
+            float priority = (-1.0) * (x*x+y*y);
+            sched_tile( b, priority, true, 0.0 );
         }
     }
 }
 
-
-void FGTileMgr::initialize_queue()
+/**
+ * Update the various queues maintained by the tilemagr (private
+ * internal function, do not call directly.)
+ */
+void FGTileMgr::update_queues()
 {
-    // First time through or we have teleported, initialize the
-    // system and load all relavant tiles
-
-    SG_LOG( SG_TERRAIN, SG_INFO, "Initialize_queue(): Updating Tile list for "
-            << current_bucket );
-    // cout << "tile cache size = " << tile_cache.get_size() << endl;
-
-    // wipe/initialize tile cache
-    // tile_cache.init();
-    previous_bucket.make_bad();
-
-    // build the local area list and schedule tiles for loading
+    osg::FrameStamp* framestamp
+        = globals->get_renderer()->getViewer()->getFrameStamp();
+    double current_time = framestamp->getReferenceTime();
+    double vis = _visibilityMeters->getDoubleValue();
+    TileEntry *e;
+    int loading=0;
+    int sz=0;
 
-    // start with the center tile and work out in concentric
-    // "rings"
+    tile_cache.set_current_time( current_time );
+    tile_cache.reset_traversal();
 
-    double visibility_meters = fgGetDouble("/environment/visibility-m");
-    schedule_needed(visibility_meters, current_bucket);
-}
+    while ( ! tile_cache.at_end() )
+    {
+        e = tile_cache.get_current();
+        // cout << "processing a tile" << endl;
+        if ( e )
+        {
+            // Prepare the ssg nodes corresponding to each tile.
+            // Set the ssg transform and update it's range selector
+            // based on current visibilty
+            e->prep_ssg_node(vis);
 
-osg::Node*
-FGTileMgr::loadTileModel(const string& modelPath, bool cacheModel)
-{
-    SGPath fullPath;
-    if (fgGetBool("/sim/paths/use-custom-scenery-data") == true) {
-        string_list sc = globals->get_fg_scenery();
-
-        for (string_list_iterator it = sc.begin(); it != sc.end(); ++it) {
-            SGPath tmpPath(*it);
-            tmpPath.append(modelPath);
-            if (tmpPath.exists()) {
-                fullPath = tmpPath;
-                break;
-            } 
+            if (( !e->is_loaded() )&&
+                ((!e->is_expired(current_time))||
+                  e->is_current_view() ))
+            {
+                // schedule tile for loading with osg pager
+                _pager->queueRequest(e->tileFileName,
+                                     e->getNode(),
+                                     e->get_priority(),
+                                     framestamp,
+                                     e->getDatabaseRequest(),
+                                     _options.get());
+                loading++;
+            }
+        } else
+        {
+            SG_LOG(SG_TERRAIN, SG_ALERT, "Warning: empty tile in cache!");
         }
-    } else {
-         fullPath.append(modelPath);
-    }
-    osg::Node* result = 0;
-    try {
-        if(cacheModel)
-            result =
-                SGModelLib::loadModel(fullPath.str(), globals->get_props(),
-                                      new FGNasalModelData);
-        else
-            result=
-                SGModelLib::loadPagedModel(modelPath, globals->get_props(),
-                                           new FGNasalModelData);
-    } catch (const sg_io_exception& exc) {
-        string m(exc.getMessage());
-        m += " ";
-        m += exc.getLocation().asString();
-        SG_LOG( SG_ALL, SG_ALERT, m );
-    } catch (const sg_exception& exc) { // XXX may be redundant
-        SG_LOG( SG_ALL, SG_ALERT, exc.getMessage());
+        tile_cache.next();
+        sz++;
     }
-    return result;
-}
-
-// Helper class for STL fun
-class TileLoad : public std::unary_function<TileCache::tile_map::value_type,
-                                            void>
-{
-public:
-    TileLoad(SceneryPager *pager, osg::FrameStamp* framestamp,
-             osg::Group* terrainBranch, osgDB::ReaderWriter::Options* options) :
-        _pager(pager), _framestamp(framestamp), _options(options) {}
-
-    TileLoad(const TileLoad& rhs) :
-        _pager(rhs._pager), _framestamp(rhs._framestamp),
-        _options(rhs._options) {}
 
-    void operator()(TileCache::tile_map::value_type& tilePair)
+    int drop_count = sz - tile_cache.get_max_cache_size();
+    if (( drop_count > 0 )&&
+         ((loading==0)||(drop_count > 10)))
     {
-        TileEntry* entry = tilePair.second;
-        if (entry->getNode()->getNumChildren() == 0) {
-            _pager->queueRequest(entry->tileFileName,
-                                 entry->getNode(),
-                                 entry->get_inner_ring() ? 10.0f : 1.0f,
-                                 _framestamp,
-                                 entry->getDatabaseRequest(),
-                                 _options);
+        long drop_index = tile_cache.get_drop_tile();
+        while ( drop_index > -1 )
+        {
+            // schedule tile for deletion with osg pager
+            TileEntry* old = tile_cache.get_tile(drop_index);
+            tile_cache.clear_entry(drop_index);
+            
+            osg::ref_ptr<osg::Object> subgraph = old->getNode();
+            old->removeFromSceneGraph();
+            delete old;
+            // zeros out subgraph ref_ptr, so subgraph is owned by
+            // the pager and will be deleted in the pager thread.
+            _pager->queueDeleteRequest(subgraph);
+            
+            if (--drop_count > 0)
+                drop_index = tile_cache.get_drop_tile();
+            else
+                drop_index = -1;
         }
     }
-private:
-    SceneryPager* _pager;
-    osg::FrameStamp* _framestamp;
-    osgDB::ReaderWriter::Options* _options;
-};
-
-/**
- * Update the various queues maintained by the tilemagr (private
- * internal function, do not call directly.)
- */
-void FGTileMgr::update_queues()
-{
-    SceneryPager* pager = FGScenery::getPagerSingleton();
-    osg::FrameStamp* framestamp
-        = globals->get_renderer()->getViewer()->getFrameStamp();
-    tile_cache.set_current_time(framestamp->getReferenceTime());
-    for_each(tile_cache.begin(), tile_cache.end(),
-             TileLoad(pager,
-                      framestamp,
-                      globals->get_scenery()->get_terrain_branch(), _options.get()));
 }
 
-
 // given the current lon/lat (in degrees), fill in the array of local
 // chunks.  If the chunk isn't already in the cache, then read it from
 // disk.
-int FGTileMgr::update( double visibility_meters )
+void FGTileMgr::update(double)
 {
-    SGVec3d viewPos = globals->get_current_view()->get_view_pos();
-    return update(SGGeod::fromCart(viewPos), visibility_meters);
+    double vis = _visibilityMeters->getDoubleValue();
+    schedule_tiles_at(globals->get_view_position(), vis);
+
+    update_queues();
+
+    // scenery loading check, triggers after each sim (tile manager) reinit
+    if (!_scenery_loaded->getBoolValue())
+    {
+        bool fdmInited = fgGetBool("sim/fdm-initialized");
+        bool positionFinalized = fgGetBool("sim/position-finalized");
+        bool sceneryOverride = _scenery_override->getBoolValue();
+        
+    // we are done if final position is set and the scenery & FDM are done.
+    // scenery-override can ignore the last two, but not position finalization.
+        if (positionFinalized && (sceneryOverride || (isSceneryLoaded() && fdmInited)))
+        {
+            _scenery_loaded->setBoolValue(true);
+            fgSplashProgress("");
+        }
+        else
+        {
+            fgSplashProgress(positionFinalized ? "loading-scenery" : "finalize-position");
+            // be nice to loader threads while waiting for initial scenery, reduce to 20fps
+            SGTimeStamp::sleepForMSec(50);
+        }
+    }
 }
 
-int FGTileMgr::update( const SGGeod& location, double visibility_meters)
+// schedule tiles for the viewer bucket
+// (FDM/AI/groundcache/... should use "schedule_scenery" instead)
+void FGTileMgr::schedule_tiles_at(const SGGeod& location, double range_m)
 {
-    SG_LOG( SG_TERRAIN, SG_DEBUG, "FGTileMgr::update()" );
-
     longitude = location.getLongitudeDeg();
     latitude = location.getLatitudeDeg();
 
     // SG_LOG( SG_TERRAIN, SG_DEBUG, "FGTileMgr::update() for "
-    //         << longitude << " " << latatitude );
+    //         << longitude << " " << latitude );
 
     current_bucket.set_bucket( location );
+
+    // schedule more tiles when visibility increased considerably
+    // TODO Calculate tile size - instead of using fixed value (5000m)
+    if (range_m - scheduled_visibility > 5000.0)
+        previous_bucket.make_bad();
+
     // SG_LOG( SG_TERRAIN, SG_DEBUG, "Updating tile list for "
     //         << current_bucket );
     fgSetInt( "/environment/current-tile-id", current_bucket.gen_index() );
 
-    // do tile load scheduling. 
+    // do tile load scheduling.
     // Note that we need keep track of both viewer buckets and fdm buckets.
     if ( state == Running ) {
-        SG_LOG( SG_TERRAIN, SG_DEBUG, "State == Running" );
+        if (last_state != state)
+        {
+            SG_LOG( SG_TERRAIN, SG_DEBUG, "State == Running" );
+        }
         if (current_bucket != previous_bucket) {
             // We've moved to a new bucket, we need to schedule any
             // needed tiles for loading.
             SG_LOG( SG_TERRAIN, SG_INFO, "FGTileMgr::update()" );
-            schedule_needed(visibility_meters, current_bucket);
+            scheduled_visibility = range_m;
+            schedule_needed(current_bucket, range_m);
+            if (_terra_sync)
+                _terra_sync->schedulePosition(latitude,longitude);
         }
+        // save bucket
+        previous_bucket = current_bucket;
     } else if ( state == Start || state == Inited ) {
-        SG_LOG( SG_TERRAIN, SG_INFO, "State == Start || Inited" );
-//        initialize_queue();
+        SG_LOG( SG_TERRAIN, SG_DEBUG, "State == Start || Inited" );
+        // do not update bucket yet (position not valid in initial loop)
         state = Running;
-        if (current_bucket != previous_bucket
-            && current_bucket.get_chunk_lon() != -1000) {
-               SG_LOG( SG_TERRAIN, SG_INFO, "FGTileMgr::update()" );
-               schedule_needed(visibility_meters, current_bucket);
-        }
+        previous_bucket.make_bad();
     }
-
-    update_queues();
-
-    // save bucket...
-    previous_bucket = current_bucket;
-
-    return 1;
+    last_state = state;
 }
 
-void FGTileMgr::prep_ssg_nodes(float vis) {
-
-    // traverse the potentially viewable tile list and update range
-    // selector and transform
-
-    TileEntry *e;
-    tile_cache.reset_traversal();
-
-    while ( ! tile_cache.at_end() ) {
-        // cout << "processing a tile" << endl;
-        if ( (e = tile_cache.get_current()) ) {
-            e->prep_ssg_node(vis);
-        } else {
-            SG_LOG(SG_INPUT, SG_ALERT, "warning ... empty tile in cache");
-        }
-        tile_cache.next();
-    }
-}
-
-bool FGTileMgr::scenery_available(const SGGeod& position, double range_m)
+/** Schedules scenery for given position. Load request remains valid for given duration
+ * (duration=0.0 => nothing is loaded).
+ * Used for FDM/AI/groundcache/... requests. Viewer uses "schedule_tiles_at" instead.
+ * Returns true when all tiles for the given position are already loaded, false otherwise.
+ */
+bool FGTileMgr::schedule_scenery(const SGGeod& position, double range_m, double duration)
 {
-  // sanity check (unfortunately needed!)
-  if (position.getLongitudeDeg() < -180 || position.getLongitudeDeg() > 180 ||
-      position.getLatitudeDeg() < -90 || position.getLatitudeDeg() > 90)
-    return false;
-  
-  SGBucket bucket(position);
-  TileEntry *te = tile_cache.get_tile(bucket);
-  if (!te || !te->is_loaded())
-    return false;
-
-  SGVec3d cartPos = SGVec3d::fromGeod(position);
-
-  // Traverse all tiles required to be there for the given visibility.
-  // This uses exactly the same algorithm like the tile scheduler.
-  double tile_width = bucket.get_width_m();
-  double tile_height = bucket.get_height_m();
-  double tile_r = 0.5*sqrt(tile_width*tile_width + tile_height*tile_height);
-  double max_dist = tile_r + range_m;
-  double max_dist2 = max_dist*max_dist;
+    const float priority = 0.0;
+    double current_longitude = position.getLongitudeDeg();
+    double current_latitude = position.getLatitudeDeg();
+    bool available = true;
+    
+    // sanity check (unfortunately needed!)
+    if (current_longitude < -180 || current_longitude > 180 ||
+        current_latitude < -90 || current_latitude > 90)
+        return false;
   
-  int xrange = (int)fabs(range_m / tile_width) + 1;
-  int yrange = (int)fabs(range_m / tile_height) + 1;
+    SGBucket bucket(position);
+    available = sched_tile( bucket, priority, false, duration );
   
-  for ( int x = -xrange; x <= xrange; ++x ) {
-    for ( int y = -yrange; y <= yrange; ++y ) {
-      // We have already checked for the center tile.
-      if ( x != 0 || y != 0 ) {
-        SGBucket b = sgBucketOffset( position.getLongitudeDeg(),
-                                     position.getLatitudeDeg(), x, y );
-        // Do not ask if it is just the next tile but way out of range.
-        if (max_dist2 < distSqr(cartPos, SGVec3d::fromGeod(b.get_center())))
-          continue;
-        TileEntry *te = tile_cache.get_tile(b);
-        if (!te || !te->is_loaded())
-          return false;
-      }
-    }
-  }
-
-  // Survived all tests.
-  return true;
-}
-
-namespace
-{
-struct IsTileLoaded :
-        public std::unary_function<TileCache::tile_map::value_type, bool>
-{
-    bool operator()(const TileCache::tile_map::value_type& tilePair) const
+    if ((!available)&&(duration==0.0))
+        return false;
+
+    SGVec3d cartPos = SGVec3d::fromGeod(position);
+
+    // Traverse all tiles required to be there for the given visibility.
+    double tile_width = bucket.get_width_m();
+    double tile_height = bucket.get_height_m();
+    double tile_r = 0.5*sqrt(tile_width*tile_width + tile_height*tile_height);
+    double max_dist = tile_r + range_m;
+    double max_dist2 = max_dist*max_dist;
+    
+    int xrange = (int)fabs(range_m / tile_width) + 1;
+    int yrange = (int)fabs(range_m / tile_height) + 1;
+
+    for ( int x = -xrange; x <= xrange; ++x )
     {
-        return tilePair.second->is_loaded();
+        for ( int y = -yrange; y <= yrange; ++y )
+        {
+            // We have already checked for the center tile.
+            if ( x != 0 || y != 0 )
+            {
+                SGBucket b = sgBucketOffset( current_longitude,
+                                             current_latitude, x, y );
+                double distance2 = distSqr(cartPos, SGVec3d::fromGeod(b.get_center()));
+                // Do not ask if it is just the next tile but way out of range.
+                if (distance2 <= max_dist2)
+                {
+                    available &= sched_tile( b, priority, false, duration );
+                    if ((!available)&&(duration==0.0))
+                        return false;
+                }
+            }
+        }
     }
-};
+
+    return available;
 }
 
+// Returns true if tiles around current view position have been loaded
 bool FGTileMgr::isSceneryLoaded()
 {
-    return (std::find_if(tile_cache.begin(), tile_cache.end(),
-                         std::not1(IsTileLoaded()))
-            == tile_cache.end());
+    double range_m = 100.0;
+    if (scheduled_visibility < range_m)
+        range_m = scheduled_visibility;
+
+    return schedule_scenery(SGGeod::fromDeg(longitude, latitude), range_m, 0.0);
 }