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>
39 * Queues tiles for loading, possibly by a separate thread.
56 * Add a tile to the end of the load queue.
57 * @param tile The tile to be loaded from disk.
58 * @param vis Current visibilty (in feet?) (see FGTileMgr::vis).
60 void add( FGTileEntry* tile );
63 * The tile loader thread will only load one tile per call to the
64 * update() method. This is a way to spread out the work of the
65 * tile loader and slow it down so it is less intrusive. For
66 * systems built without thead support this is a no-op.
71 * Returns whether the load queue is empty (contains no elements).
72 * @return true if load queue is empty otherwise returns false.
74 // bool empty() const { return tile_queue.empty(); }
82 * FIFO queue of tiles to load from data files.
84 SGBlockingQueue< FGTileEntry* > tile_queue;
88 * Base name of directory containing tile data file.
94 * Maximum number of threads to create for loading tiles.
96 enum { MAX_THREADS = 1 };
99 * This class represents the thread of execution responsible for
102 class LoaderThread : public SGThread
105 LoaderThread( FGTileLoader* l ) : loader(l) {}
109 * Reads the tile from disk.
114 FGTileLoader* loader;
119 LoaderThread( const LoaderThread& );
120 LoaderThread& operator=( const LoaderThread& );
123 friend class LoaderThread;
126 * Array of loading threads.
128 LoaderThread* threads[ MAX_THREADS ];
131 * Lock and synchronize access to tile queue.
134 SGCondition frame_cond;
137 * Thread cleanup handler.
139 friend void cleanup_handler( void* );
140 #endif // ENABLE_THREADS
143 #endif // FG_TILE_LOADER_HXX