1 // TileCache.cxx -- routines to handle scenery tile caching
3 // Written by Curtis Olson, started December 2000.
5 // Copyright (C) 2000 Curtis L. Olson - http://www.flightgear.org/~curt
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
27 #include <simgear/bucket/newbucket.hxx>
28 #include <simgear/debug/logstream.hxx>
29 #include <simgear/misc/sg_path.hxx>
31 #include "tileentry.hxx"
32 #include "tilecache.hxx"
34 TileCache::TileCache( void ) :
35 max_cache_size(100), current_time(0.0)
41 TileCache::~TileCache( void )
43 tile_map_iterator it = tile_cache.begin();
44 for (; it != tile_cache.end(); ++it) {
45 TileEntry* tile = it->second;
46 tile->removeFromSceneGraph();
52 // Free a tile cache entry
53 void TileCache::entry_free( long tile_index ) {
54 SG_LOG( SG_TERRAIN, SG_DEBUG, "FREEING CACHE ENTRY = " << tile_index );
55 TileEntry *tile = tile_cache[tile_index];
56 tile->removeFromSceneGraph();
57 tile_cache.erase( tile_index );
62 // Initialize the tile cache subsystem
63 void TileCache::init( void ) {
64 SG_LOG( SG_TERRAIN, SG_INFO, "Initializing the tile cache." );
66 SG_LOG( SG_TERRAIN, SG_INFO, " max cache size = "
68 SG_LOG( SG_TERRAIN, SG_INFO, " current cache size = "
69 << tile_cache.size() );
73 SG_LOG( SG_TERRAIN, SG_INFO, " done with init()" );
77 // Search for the specified "bucket" in the cache
78 bool TileCache::exists( const SGBucket& b ) const {
79 long tile_index = b.gen_index();
80 const_tile_map_iterator it = tile_cache.find( tile_index );
82 return ( it != tile_cache.end() );
86 // Return the index of a tile to be dropped from the cache, return -1 if
87 // nothing available to be removed.
88 long TileCache::get_drop_tile() {
90 double min_time = DBL_MAX;
91 float priority = FLT_MAX;
93 tile_map_iterator current = tile_cache.begin();
94 tile_map_iterator end = tile_cache.end();
96 for ( ; current != end; ++current ) {
97 long index = current->first;
98 TileEntry *e = current->second;
99 if (( !e->is_current_view() )&&
100 ( e->is_expired(current_time) ))
102 if (e->is_expired(current_time - 1.0)&&
105 /* Immediately drop "empty" tiles which are no longer used/requested, and were last requested > 1 second ago...
106 * Allow a 1 second timeout since an empty tiles may just be loaded...
108 SG_LOG( SG_TERRAIN, SG_DEBUG, " dropping an unused and empty tile");
112 if (( e->get_time_expired() < min_time )||
113 (( e->get_time_expired() == min_time)&&
114 ( priority > e->get_priority())))
116 // drop oldest tile with lowest priority
117 min_time = e->get_time_expired();
118 priority = e->get_priority();
124 SG_LOG( SG_TERRAIN, SG_DEBUG, " index = " << min_index );
125 SG_LOG( SG_TERRAIN, SG_DEBUG, " min_time = " << min_time );
130 long TileCache::get_first_invisible_tile() const
132 const_tile_map_iterator current = tile_cache.begin();
133 const_tile_map_iterator end = tile_cache.end();
135 for ( ; current != end; ++current ) {
136 TileEntry *e = current->second;
137 if (!e->is_current_view())
139 return current->first;
143 return -1; // no expired tile found
147 // Clear all flags indicating tiles belonging to the current view
148 void TileCache::clear_current_view()
150 tile_map_iterator current = tile_cache.begin();
151 tile_map_iterator end = tile_cache.end();
153 for ( ; current != end; ++current ) {
154 TileEntry *e = current->second;
155 if (e->is_current_view())
157 // update expiry time for tiles belonging to most recent position
158 e->update_time_expired( current_time );
159 e->set_current_view( false );
164 // Clear a cache entry, note that the cache only holds pointers
165 // and this does not free the object which is pointed to.
166 void TileCache::clear_entry( long tile_index ) {
167 tile_cache.erase( tile_index );
171 // Clear all completely loaded tiles (ignores partially loaded tiles)
172 void TileCache::clear_cache() {
173 std::vector<long> indexList;
174 tile_map_iterator current = tile_cache.begin();
175 tile_map_iterator end = tile_cache.end();
177 for ( ; current != end; ++current ) {
178 long index = current->first;
179 TileEntry *e = current->second;
180 if ( e->is_loaded() ) {
181 e->tile_bucket.make_bad();
182 // entry_free modifies tile_cache, so store index and call entry_free() later;
183 indexList.push_back( index);
186 for (unsigned int it = 0; it < indexList.size(); it++) {
187 entry_free( indexList[ it]);
192 * Create a new tile and schedule it for loading.
194 bool TileCache::insert_tile( TileEntry *e ) {
195 // register tile in the cache
196 long tile_index = e->get_tile_bucket().gen_index();
197 tile_cache[tile_index] = e;
198 e->update_time_expired(current_time);
203 // update tile's priority and expiry time according to current request
204 void TileCache::request_tile(TileEntry* t,float priority,bool current_view,double request_time)
206 if ((!current_view)&&(request_time<=0.0))
209 // update priority when higher - or old request has expired
210 if ((t->is_expired(current_time))||
211 (priority > t->get_priority()))
213 t->set_priority( priority );
218 t->update_time_expired( current_time );
219 t->set_current_view( true );
223 t->update_time_expired( current_time+request_time );