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flightgear/src/Scenery/tilemgr.cxx
curt e807c7f95c A long, long time ago, a bug was inadvertently introduced into the threaded
metar fetcher.  Effectively this caused the metar thread and the main
thread to both attempt to fetch weather data.  This could lead to long pauses
when the main thread decided to fetch the weather, and introduced a race
condition that could cause a segfault/crash.

Investigating this issue, I discovered that even longer ago, someone confused
#defines and #ifdef symbols with C/C++ variables.  If I #define XYZ 0 it is
defined so #ifdef XYZ is true, not false like a variable.  Our thread
detection made this mistake and there were follow up patches to work around
it.

So I fixed the configure script (ahhh, reading the autoconf manual is highly
recommended excercise for people editing the configure.ac file.)  I also
discovered that we were hardwiring with_threads=yes with no way via configure
options to disable threads from the build so I fixed that.

Then I patched up the #ifdef's scattered through the code to match the
configure script changes, oh and by the way, I stumbled upon a past typo
that led to the race condition in the metar fetching thread and fixed that.
2005-11-22 17:02:31 +00:00

522 lines
16 KiB
C++

// tilemgr.cxx -- routines to handle dynamic management of scenery tiles
//
// Written by Curtis Olson, started January 1998.
//
// 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
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// 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.
//
// $Id$
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#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 <simgear/scene/model/shadowvolume.hxx>
#include <Main/globals.hxx>
#include <Main/fg_props.hxx>
#include <Main/viewer.hxx>
#include "newcache.hxx"
#include "scenery.hxx"
#include "tilemgr.hxx"
#define TEST_LAST_HIT_CACHE
#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;
extern SGShadowVolume *shadows;
// Constructor
FGTileMgr::FGTileMgr():
state( Start ),
current_tile( NULL ),
vis( 16000 )
{
}
// Destructor
FGTileMgr::~FGTileMgr() {
}
// Initialize the Tile Manager subsystem
int FGTileMgr::init() {
SG_LOG( SG_TERRAIN, SG_INFO, "Initializing Tile Manager subsystem." );
tile_cache.init();
#if 0
// instead it's just a lot easier to let any pending work flush
// through, rather than trying to arrest the queue and nuke all
// the various work at all the various stages and get everything
// cleaned up properly.
while ( ! attach_queue.empty() ) {
attach_queue.pop();
}
while ( ! model_queue.empty() ) {
#if defined(ENABLE_THREADS)
FGDeferredModel* dm = model_queue.pop();
#else
FGDeferredModel* dm = model_queue.front();
model_queue.pop();
#endif
delete dm;
}
loader.reinit();
#endif
hit_list.clear();
state = Inited;
previous_bucket.make_bad();
current_bucket.make_bad();
longitude = latitude = -1000.0;
return 1;
}
// schedule a tile for loading
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 );
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
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 {
t->set_inner_ring( is_inner_ring );
}
}
// schedule a needed buckets for loading
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 << ")" );
SG_LOG( SG_TERRAIN, SG_ALERT,
"This is a FATAL error. Exiting!" );
exit(-1);
}
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;
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;
// 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, 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, 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 );
}
}
}
}
void FGTileMgr::initialize_queue()
{
// 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
// start with the center tile and work out in concentric
// "rings"
double visibility_meters = fgGetDouble("/environment/visibility-m");
schedule_needed(visibility_meters, current_bucket);
// do we really want to lose this? CLO
#if 0
// Now force a load of the center tile and inner ring so we
// have something to see in our first frame.
int i;
for ( i = 0; i < 9; ++i ) {
if ( load_queue.size() ) {
SG_LOG( SG_TERRAIN, SG_DEBUG,
"Load queue not empty, loading a tile" );
SGBucket pending = load_queue.front();
load_queue.pop_front();
load_tile( pending );
}
}
#endif
}
/**
* return current status of queues
*
*/
bool FGTileMgr::all_queues_empty() {
return attach_queue.empty() && model_queue.empty();
}
/**
* 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;
while ( model_queue.size() > 200 || processed_one == false ) {
processed_one = true;
if ( model_queue.size() > 200 ) {
SG_LOG( SG_TERRAIN, SG_INFO,
"Alert: catching up on model load queue" );
}
// 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
// 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 ) {
ssgTexturePath( (char *)(dm->get_texture_path().c_str()) );
try {
ssgEntity *obj_model =
globals->get_model_lib()->load_model( ".",
dm->get_model_path(),
globals->get_props(),
globals->get_sim_time_sec() );
if ( obj_model != NULL ) {
dm->get_obj_trans()->addKid( obj_model );
shadows->addOccluder( (ssgBranch *) obj_model->getParent(0),
SGShadowVolume::occluderTypeTileObject,
(ssgBranch *) dm->get_tile()->get_terra_transform());
}
} catch (const sg_exception& exc) {
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();
if ( !attach_queue.empty() ) {
#if defined(ENABLE_THREADS)
FGTileEntry* e = attach_queue.pop();
#else
FGTileEntry* e = attach_queue.front();
attach_queue.pop();
#endif
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;
}
}
}
}
// 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;
// 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 );
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();
}
update_queues();
// save bucket...
previous_bucket = current_bucket;
return 1;
}
// 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);
}
}
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( viewpos, up, vis);
} else {
SG_LOG(SG_INPUT, SG_ALERT, "warning ... empty tile in cache");
}
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;
}