//
// Written by Curtis Olson, started January 1998.
//
-// Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
+// Copyright (C) 1997 Curtis L. Olson - http://www.flightgear.org/~curt
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
-// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
// $Id$
# include <config.h>
#endif
-#ifdef HAVE_WINDOWS_H
-# include <windows.h>
-#endif
-
-#include <GL/glut.h>
-
-#include <plib/ssg.h>
-
#include <simgear/constants.h>
#include <simgear/debug/logstream.hxx>
#include <simgear/math/point3d.hxx>
#include <simgear/math/polar3d.hxx>
#include <simgear/math/sg_geodesy.hxx>
#include <simgear/math/vector.hxx>
+#include <simgear/structure/exception.hxx>
+#include <simgear/scene/model/modellib.hxx>
#include <Main/globals.hxx>
-#include <Objects/obj.hxx>
-
-#ifndef FG_OLD_WEATHER
-# include <WeatherCM/FGLocalWeatherDatabase.h>
-#else
-# include <Weather/weather.hxx>
-#endif
+#include <Main/fg_props.hxx>
+#include <Main/viewer.hxx>
+#include <Scripting/NasalSys.hxx>
#include "newcache.hxx"
#include "scenery.hxx"
#define TEST_LAST_HIT_CACHE
-extern ssgRoot *scene;
-extern ssgBranch *terrain;
-extern ssgBranch *ground;
-
-// the tile manager
-FGTileMgr global_tile_mgr;
-
-
-// a temporary hack until we get everything rewritten with sgdVec3
-static inline Point3D operator + (const Point3D& a, const sgdVec3 b)
-{
- return Point3D(a.x()+b[0], a.y()+b[1], a.z()+b[2]);
-}
-
-#ifdef ENABLE_THREADS
+#if defined(ENABLE_THREADS)
SGLockedQueue<FGTileEntry *> FGTileMgr::attach_queue;
SGLockedQueue<FGDeferredModel *> FGTileMgr::model_queue;
#else
queue<FGTileEntry *> FGTileMgr::attach_queue;
queue<FGDeferredModel *> FGTileMgr::model_queue;
#endif // ENABLE_THREADS
+queue<FGTileEntry *> FGTileMgr::delete_queue;
+bool FGTileMgr::tile_filter = true;
// Constructor
FGTileMgr::FGTileMgr():
state( Start ),
- vis( 16000 ),
- counter_hack(0)
+ current_tile( NULL ),
+ vis( 16000 )
{
}
}
while ( ! model_queue.empty() ) {
-#ifdef ENABLE_THREADS
- FGDeferredModel* dm = model_queue.pop();
+#if defined(ENABLE_THREADS)
+ FGDeferredModel* dm = model_queue.pop();
#else
FGDeferredModel* dm = model_queue.front();
model_queue.pop();
loader.reinit();
#endif
- hit_list.clear();
-
state = Inited;
previous_bucket.make_bad();
current_bucket.make_bad();
longitude = latitude = -1000.0;
- last_longitude = last_latitude = -1000.0;
-
+
return 1;
}
// schedule a tile for loading
-void FGTileMgr::sched_tile( const SGBucket& b ) {
+void FGTileMgr::sched_tile( const SGBucket& b, const bool is_inner_ring ) {
// see if tile already exists in the cache
FGTileEntry *t = tile_cache.get_tile( b );
if ( t == NULL ) {
+ // make space in the cache
+ while ( (int)tile_cache.get_size() > tile_cache.get_max_cache_size() ) {
+ long index = tile_cache.get_oldest_tile();
+ if ( index >= 0 ) {
+ FGTileEntry *old = tile_cache.get_tile( index );
+ // OSGFIXME
+// shadows->deleteOccluderFromTile( (ssgBranch *) old->get_terra_transform() );
+ old->disconnect_ssg_nodes();
+ delete_queue.push( old );
+ tile_cache.clear_entry( index );
+ } else {
+ // nothing to free ?!? forge ahead
+ break;
+ }
+ }
+
// create a new entry
FGTileEntry *e = new FGTileEntry( b );
// insert the tile into the cache
- tile_cache.insert_tile( e );
-
- // Schedule tile for loading
- loader.add( e );
- }
-}
-
-
-static void CurrentNormalInLocalPlane(sgVec3 dst, sgVec3 src) {
- sgVec3 tmp;
- sgSetVec3(tmp, src[0], src[1], src[2] );
- sgMat4 TMP;
- sgTransposeNegateMat4 ( TMP, globals->get_current_view()->get_UP() ) ;
- sgXformVec3(tmp, tmp, TMP);
- sgSetVec3(dst, tmp[2], tmp[1], tmp[0] );
-}
-
-
-// Determine scenery altitude via ssg. Normally this just happens
-// when we render the scene, but we'd also like to be able to do this
-// explicitely. lat & lon are in radians. view_pos in current world
-// coordinate translated near (0,0,0) (in meters.) Returns result in
-// meters.
-bool FGTileMgr::current_elev_ssg( sgdVec3 abs_view_pos, double *terrain_elev ) {
- sgdVec3 view_pos;
- sgdVec3 sc;
- sgdSetVec3( sc, scenery.center.x(), scenery.center.y(), scenery.center.z());
- sgdSubVec3( view_pos, abs_view_pos, sc );
-
- sgdVec3 orig, dir;
- sgdCopyVec3(orig, view_pos );
- sgdCopyVec3(dir, abs_view_pos );
-
- hit_list.Intersect( terrain, orig, dir );
-
- int this_hit=0;
- Point3D geoc;
- double result = -9999;
-
- int hitcount = hit_list.num_hits();
- for ( int i = 0; i < hitcount; ++i ) {
- geoc = sgCartToPolar3d( scenery.center + hit_list.get_point(i) );
- double lat_geod, alt, sea_level_r;
- sgGeocToGeod(geoc.lat(), geoc.radius(), &lat_geod,
- &alt, &sea_level_r);
- if ( alt > result && alt < 10000 ) {
- result = alt;
- this_hit = i;
- }
- }
-
- if ( result > -9000 ) {
- *terrain_elev = result;
- scenery.cur_radius = geoc.radius();
- sgVec3 tmp;
- sgSetVec3(tmp, hit_list.get_normal(this_hit));
- // cout << "cur_normal: " << tmp[0] << " " << tmp[1] << " "
- // << tmp[2] << endl;
- /* ssgState *IntersectedLeafState =
- ((ssgLeaf*)hit_list.get_entity(this_hit))->getState(); */
- CurrentNormalInLocalPlane(tmp, tmp);
- sgdSetVec3( scenery.cur_normal, tmp );
- // cout << "NED: " << tmp[0] << " " << tmp[1] << " " << tmp[2] << endl;
- return true;
+ if ( tile_cache.insert_tile( e ) ) {
+ // Schedule tile for loading
+ loader.add( e );
+ } else {
+ // insert failed (cache full with no available entries to
+ // delete.) Try again later
+ delete e;
+ }
} else {
- SG_LOG( SG_TERRAIN, SG_INFO, "no terrain intersection" );
- *terrain_elev = 0.0;
- float *up = globals->get_current_view()->get_world_up();
- sgdSetVec3(scenery.cur_normal, up[0], up[1], up[2]);
- return false;
+ t->set_inner_ring( is_inner_ring );
}
}
// schedule a needed buckets for loading
-void FGTileMgr::schedule_needed() {
-#ifndef FG_OLD_WEATHER
- if ( WeatherDatabase != NULL ) {
- vis = WeatherDatabase->getWeatherVisibility();
- } else {
- vis = 16000;
+void FGTileMgr::schedule_needed( double vis, const SGBucket& curr_bucket) {
+ // sanity check (unfortunately needed!)
+ if ( longitude < -180.0 || longitude > 180.0
+ || latitude < -90.0 || latitude > 90.0 )
+ {
+ 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);
}
-#else
- vis = current_weather.get_visibility();
-#endif
- // cout << "visibility = " << vis << endl;
- double tile_width = current_bucket.get_width_m();
- double tile_height = current_bucket.get_height_m();
+ 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;
+ // << tile_height << endl;
xrange = (int)(vis / tile_width) + 1;
yrange = (int)(vis / tile_height) + 1;
if ( xrange < 1 ) { xrange = 1; }
if ( yrange < 1 ) { yrange = 1; }
+
+ // note * 2 at end doubles cache size (for fdm and viewer)
+ tile_cache.set_max_cache_size( (2*xrange + 2) * (2*yrange + 2) * 2 );
// cout << "xrange = " << xrange << " yrange = " << yrange << endl;
+ // cout << "max cache size = " << tile_cache.get_max_cache_size()
+ // << " current cache size = " << tile_cache.get_size() << endl;
- tile_cache.set_max_cache_size( (2*xrange + 2) * (2*yrange + 2) );
+ // 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();
SGBucket b;
// schedule center tile first so it can be loaded first
b = sgBucketOffset( longitude, latitude, 0, 0 );
- sched_tile( b );
+ sched_tile( b, true );
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 );
- }
- }
+ 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 );
- }
- }
+ 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 );
+ }
+ }
}
}
// First time through or we have teleported, initialize the
// system and load all relavant tiles
- SG_LOG( SG_TERRAIN, SG_INFO, "Updating Tile list for " << current_bucket );
+ 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
// start with the center tile and work out in concentric
// "rings"
- schedule_needed();
+ double visibility_meters = fgGetDouble("/environment/visibility-m");
+ schedule_needed(visibility_meters, current_bucket);
// do we really want to lose this? CLO
#if 0
#endif
}
+/**
+ * return current status of queues
+ *
+ */
-// 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 lon, double lat ) {
- SG_LOG( SG_TERRAIN, SG_DEBUG, "FGTileMgr::update()" );
+bool FGTileMgr::all_queues_empty() {
+ return attach_queue.empty() && model_queue.empty();
+}
- // FGInterface *f = current_aircraft.fdm_state;
- // lonlat for this update
- // longitude = f->get_Longitude() * SGD_RADIANS_TO_DEGREES;
- // latitude = f->get_Latitude() * SGD_RADIANS_TO_DEGREES;
- longitude = lon;
- latitude = lat;
- // SG_LOG( SG_TERRAIN, SG_DEBUG, "lon "<< lonlat[LON] <<
- // " lat " << lonlat[LAT] );
+/**
+ * Update the various queues maintained by the tilemagr (private
+ * internal function, do not call directly.)
+ */
+void FGTileMgr::update_queues()
+{
+ // load the next model in the load queue. Currently this must
+ // happen in the render thread because model loading can trigger
+ // texture loading which involves use of the opengl api. Skip any
+ // models belonging to not loaded tiles (i.e. the tile was removed
+ // before we were able to load some of the associated models.)
+ if ( !model_queue.empty() ) {
+ bool processed_one = false;
- current_bucket.set_bucket( longitude, latitude );
- // SG_LOG( SG_TERRAIN, SG_DEBUG, "Updating Tile list for " << current_bucket );
+ while ( model_queue.size() > 200 || processed_one == false ) {
+ processed_one = true;
- if ( tile_cache.exists( current_bucket ) ) {
- current_tile = tile_cache.get_tile( current_bucket );
- scenery.next_center = current_tile->center;
- } else {
- SG_LOG( SG_TERRAIN, SG_WARN, "Tile not found (Ok if initializing)" );
- }
+ if ( model_queue.size() > 200 ) {
+ SG_LOG( SG_TERRAIN, SG_INFO,
+ "Alert: catching up on model load queue" );
+ }
- if ( state == Running ) {
- if ( !(current_bucket == previous_bucket) ) {
- // We've moved to a new bucket, we need to schedule any
- // needed tiles for loading.
- schedule_needed();
- }
- } else if ( state == Start || state == Inited ) {
- initialize_queue();
- state = Running;
- }
+ // cout << "loading next model ..." << endl;
+ // load the next tile in the queue
+#if defined(ENABLE_THREADS)
+ FGDeferredModel* dm = model_queue.pop();
+#else
+ FGDeferredModel* dm = model_queue.front();
+ model_queue.pop();
+#endif
- // load the next tile in the load queue (or authorize the next
- // load in the case of the threaded tile pager)
+ // only load the model if the tile still exists in the
+ // tile cache
+ FGTileEntry *t = tile_cache.get_tile( dm->get_bucket() );
+ if ( t != NULL ) {
+ //OSGFIXME
+// ssgTexturePath( (char *)(dm->get_texture_path().c_str()) );
+ try {
+ osg::Node *obj_model =
+ globals->get_model_lib()->load_model( ".",
+ dm->get_model_path(),
+ globals->get_props(),
+ globals->get_sim_time_sec(),
+ dm->get_cache_state(),
+ new FGNasalModelData );
+ if ( obj_model != NULL ) {
+ dm->get_obj_trans()->addChild( obj_model );
+ //OSGFIXME
+// shadows->addOccluder( (ssgBranch *) obj_model->getParent(0),
+// SGShadowVolume::occluderTypeTileObject,
+// (ssgBranch *) dm->get_tile()->get_terra_transform());
+ }
+ } 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());
+ }
+
+ dm->get_tile()->dec_pending_models();
+ }
+ delete dm;
+ }
+ }
+
+ // Notify the tile loader that it can load another tile
loader.update();
- // load the next model in the load queue. Currently this must
- // happen in the render thread because model loading can trigger
- // texture loading which involves use of the opengl api.
- if ( !model_queue.empty() ) {
- cout << "loading next model ..." << endl;
- // load the next tile in the queue
-#ifdef ENABLE_THREADS
- FGDeferredModel* dm = model_queue.pop();
+ if ( !attach_queue.empty() ) {
+#if defined(ENABLE_THREADS)
+ FGTileEntry* e = attach_queue.pop();
#else
- FGDeferredModel* dm = model_queue.front();
- model_queue.pop();
+ FGTileEntry* e = attach_queue.front();
+ attach_queue.pop();
#endif
-
- ssgTexturePath( (char *)(dm->get_texture_path().c_str()) );
- ssgEntity *obj_model
- = ssgLoad( (char *)(dm->get_model_path().c_str()) );
- if ( obj_model != NULL ) {
- dm->get_obj_trans()->addKid( obj_model );
+ e->add_ssg_nodes( globals->get_scenery()->get_terrain_branch(),
+ globals->get_scenery()->get_gnd_lights_root(),
+ globals->get_scenery()->get_vasi_lights_root(),
+ globals->get_scenery()->get_rwy_lights_root(),
+ globals->get_scenery()->get_taxi_lights_root() );
+ // cout << "Adding ssg nodes for "
+ }
+
+ if ( !delete_queue.empty() ) {
+ // cout << "delete queue = " << delete_queue.size() << endl;
+ bool processed_one = false;
+
+ while ( delete_queue.size() > 30 || processed_one == false ) {
+ processed_one = true;
+
+ if ( delete_queue.size() > 30 ) {
+ // uh oh, delete queue is blowing up, we aren't clearing
+ // it fast enough. Let's just panic, well not panic, but
+ // get real serious and agressively free up some tiles so
+ // we don't explode our memory usage.
+
+ SG_LOG( SG_TERRAIN, SG_ALERT,
+ "Warning: catching up on tile delete queue" );
+ }
+
+ FGTileEntry* e = delete_queue.front();
+ if ( e->free_tile() ) {
+ delete_queue.pop();
+ delete e;
+ }
}
- dm->get_tile()->dec_pending_models();
+ }
+}
+
+
+// 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 )
+{
+ SGLocation *location = globals->get_current_view()->getSGLocation();
+ return update( location, visibility_meters );
+}
+
+
+int FGTileMgr::update( SGLocation *location, double visibility_meters )
+{
+ SG_LOG( SG_TERRAIN, SG_DEBUG, "FGTileMgr::update()" );
+
+ longitude = location->getLongitude_deg();
+ latitude = location->getLatitude_deg();
+ // add 1.0m to the max altitude to give a little leeway to the
+ // ground reaction code.
+ altitude_m = location->getAltitudeASL_ft() * SG_FEET_TO_METER + 1.0;
- delete dm;
+ // if current altitude is apparently not initialized, set max
+ // altitude to something big.
+ if ( altitude_m < -1000 ) {
+ altitude_m = 10000;
}
+ // SG_LOG( SG_TERRAIN, SG_DEBUG, "FGTileMgr::update() for "
+ // << longitude << " " << latatitude );
- if ( scenery.center == Point3D(0.0) ) {
- // initializing
- cout << "initializing scenery current elevation ... " << endl;
- sgdVec3 tmp_abs_view_pos;
- sgVec3 tmp_view_pos;
-
- Point3D geod_pos = Point3D( longitude * SGD_DEGREES_TO_RADIANS,
- latitude * SGD_DEGREES_TO_RADIANS,
- 0.0);
- Point3D tmp = sgGeodToCart( geod_pos );
- scenery.center = tmp;
- sgdSetVec3( tmp_abs_view_pos, tmp.x(), tmp.y(), tmp.z() );
-
- // cout << "abs_view_pos = " << tmp_abs_view_pos << endl;
- prep_ssg_nodes();
- sgSetVec3( tmp_view_pos, 0.0, 0.0, 0.0 );
- double tmp_elev;
- if ( current_elev_ssg(tmp_abs_view_pos, &tmp_elev) ) {
- scenery.cur_elev = tmp_elev;
- } else {
- scenery.cur_elev = 0.0;
- }
- cout << "result = " << scenery.cur_elev << endl;
- } else {
- // cout << "abs view pos = " << current_view.abs_view_pos
- // << " view pos = " << current_view.view_pos << endl;
- double tmp_elev;
- if ( current_elev_ssg(globals->get_current_view()->get_abs_view_pos(),
- &tmp_elev) )
- {
- scenery.cur_elev = tmp_elev;
- } else {
- scenery.cur_elev = 0.0;
- }
+ current_bucket.set_bucket( longitude, latitude );
+ // 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.
+ // 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 (!(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);
+ }
+ } else if ( state == Start || state == Inited ) {
+ SG_LOG( SG_TERRAIN, SG_INFO, "State == Start || Inited" );
+// initialize_queue();
+ state = Running;
+
+ // load the next tile in the load queue (or authorize the next
+ // load in the case of the threaded tile pager)
+ loader.update();
}
- // cout << "current elevation (ssg) == " << scenery.cur_elev << endl;
+ update_queues();
+ // save bucket...
previous_bucket = current_bucket;
- last_longitude = longitude;
- last_latitude = latitude;
-
- // activate loader thread one out of every 5 frames
- counter_hack = (counter_hack + 1) % 5;
- if ( !counter_hack ) {
- // Notify the tile loader that it can load another tile
- // loader.update();
-
- if ( !attach_queue.empty() ) {
-#ifdef ENABLE_THREADS
- FGTileEntry* e = attach_queue.pop();
-#else
- FGTileEntry* e = attach_queue.front();
- attach_queue.pop();
-#endif
- e->add_ssg_nodes( terrain, ground );
- // cout << "Adding ssg nodes for "
- }
- }
return 1;
}
-void FGTileMgr::prep_ssg_nodes() {
- float vis = 0.0;
-
-#ifndef FG_OLD_WEATHER
- if ( WeatherDatabase ) {
- vis = WeatherDatabase->getWeatherVisibility();
- } else {
- vis = 16000;
+// timer event driven call to scheduler for the purpose of refreshing the tile timestamps
+void FGTileMgr::refresh_view_timestamps() {
+ SG_LOG( SG_TERRAIN, SG_INFO,
+ "Refreshing timestamps for " << current_bucket.get_center_lon()
+ << " " << current_bucket.get_center_lat() );
+ if ( longitude >= -180.0 && longitude <= 180.0
+ && latitude >= -90.0 && latitude <= 90.0 )
+ {
+ schedule_needed(fgGetDouble("/environment/visibility-m"), current_bucket);
}
-#else
- vis = current_weather.get_visibility();
-#endif
- // cout << "visibility = " << vis << endl;
+}
+
+void FGTileMgr::prep_ssg_nodes( SGLocation *location, float vis ) {
// traverse the potentially viewable tile list and update range
// selector and transform
+ float *up = location->get_world_up();
+
FGTileEntry *e;
tile_cache.reset_traversal();
+ const double *vp = location->get_absolute_view_pos();
+ Point3D viewpos(vp[0], vp[1], vp[2]);
while ( ! tile_cache.at_end() ) {
// cout << "processing a tile" << endl;
if ( (e = tile_cache.get_current()) ) {
- e->prep_ssg_node( scenery.center, vis);
+ e->prep_ssg_node( viewpos, up, vis);
} else {
- cout << "warning ... empty tile in cache" << endl;
+ SG_LOG(SG_INPUT, SG_ALERT, "warning ... empty tile in cache");
}
- tile_cache.next();
- }
+ tile_cache.next();
+ }
+}
+
+bool FGTileMgr::set_tile_filter( bool f ) {
+ bool old = tile_filter;
+ tile_filter = f;
+ return old;
+}
+
+int FGTileMgr::tile_filter_cb( ssgEntity *, int )
+{
+ return tile_filter ? 1 : 0;
+}
+
+bool FGTileMgr::scenery_available(double lat, double lon, double range_m)
+{
+ // sanity check (unfortunately needed!)
+ if ( lon <= -180.0 || lon >= 180.0 || lat <= -90.0 || lat >= 90.0 )
+ return false;
+
+ SGBucket bucket(lon, lat);
+ FGTileEntry *te = tile_cache.get_tile(bucket);
+ if (!te || !te->is_loaded())
+ return false;
+
+ // 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();
+
+ 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 ) {
+ for ( int y = -yrange; y <= yrange; ++y ) {
+ // We have already checked for the center tile.
+ if ( x != 0 || y != 0 ) {
+ SGBucket b = sgBucketOffset( lon, lat, x, y );
+ FGTileEntry *te = tile_cache.get_tile(b);
+ if (!te || !te->is_loaded())
+ return false;
+ }
+ }
+ }
+
+ // Survived all tests.
+ return true;
}