1 // FGTileLoader - Queue scenery tiles for loading.
3 // Written by Bernie Bright, started March 2001.
5 // Copyright (C) 2001 Bernard Bright - bbright@bigpond.net.au
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., 675 Mass Ave, Cambridge, MA 02139, USA.
24 #ifndef FG_TILE_LOADER_HXX
25 #define FG_TILE_LOADER_HXX
27 #include <simgear/bucket/newbucket.hxx>
28 #include <simgear/misc/sg_path.hxx>
31 # include <simgear/threads/SGThread.hxx>
32 # include <simgear/threads/SGQueue.hxx>
41 * Queues tiles for loading, possibly by a separate thread.
58 * Flush anything in pending load queue without doing the work
59 * Leave the free queue intact since that's are only record of
60 * things we need to remove.
65 * Add a tile to the end of the load queue.
66 * @param tile The tile to be loaded from disk.
68 void add( FGTileEntry* tile );
70 #ifdef WISH_PLIB_WAS_THREADED // but it isn't
72 * Remove a tile from memory.
73 * @param tile The tile to be removed from memory.
75 void remove( FGTileEntry* tile );
79 * The tile loader thread will only load one tile per call to the
80 * update() method. This is a way to spread out the work of the
81 * tile loader and slow it down so it is less intrusive. For
82 * systems built without thead support this is a no-op.
87 * Returns whether the load queue is empty (contains no elements).
88 * @return true if load queue is empty otherwise returns false.
90 // bool empty() const { return tile_load_queue.empty(); }
98 * FIFO queue of tiles to load from data files.
100 SGBlockingQueue< FGTileEntry * > tile_load_queue;
101 // SGBlockingQueue< FGTileEntry * > tile_free_queue;
103 queue< FGTileEntry * > tile_load_queue;
104 // queue< FGTileEntry * > tile_free_queue;
108 * Base name of directory containing tile data file.
112 #ifdef ENABLE_THREADS
114 * Maximum number of threads to create for loading tiles.
116 enum { MAX_THREADS = 1 };
119 * This class represents the thread of execution responsible for
122 class LoaderThread : public SGThread
125 LoaderThread( FGTileLoader* l ) : loader(l) {}
129 * Reads the tile from disk.
134 FGTileLoader* loader;
139 LoaderThread( const LoaderThread& );
140 LoaderThread& operator=( const LoaderThread& );
143 friend class LoaderThread;
146 * Array of loading threads.
148 LoaderThread* threads[ MAX_THREADS ];
151 * Lock and synchronize access to tile queue.
154 SGCondition frame_cond;
157 * Thread cleanup handler.
159 friend void cleanup_handler( void* );
160 #endif // ENABLE_THREADS
163 #endif // FG_TILE_LOADER_HXX