143 lines
3.3 KiB
C++
143 lines
3.3 KiB
C++
// FGTileLoader - Queue scenery tiles for loading.
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//
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// Written by Bernie Bright, started March 2001.
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//
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// Copyright (C) 2001 Bernard Bright - bbright@bigpond.net.au
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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//
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// $Id$
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#ifndef FG_TILE_LOADER_HXX
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#define FG_TILE_LOADER_HXX
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#include <simgear/bucket/newbucket.hxx>
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#include <simgear/misc/sg_path.hxx>
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#ifdef ENABLE_THREADS
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# include <simgear/threads/SGThread.hxx>
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# include <simgear/threads/SGQueue.hxx>
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#endif
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// Forward reference.
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class FGTileEntry;
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/**
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* Queues tiles for loading, possibly by a separate thread.
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*/
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class FGTileLoader
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{
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public:
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/**
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* Constructor.
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*/
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FGTileLoader();
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/**
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* Destructor.
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*/
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~FGTileLoader();
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/**
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* Add a tile to the end of the load queue.
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* @param tile The tile to be loaded from disk.
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* @param vis Current visibilty (in feet?) (see FGTileMgr::vis).
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*/
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void add( FGTileEntry* tile );
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/**
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* The tile loader thread will only load one tile per call to the
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* update() method. This is a way to spread out the work of the
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* tile loader and slow it down so it is less intrusive. For
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* systems built without thead support this is a no-op.
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*/
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void update();
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/**
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* Returns whether the load queue is empty (contains no elements).
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* @return true if load queue is empty otherwise returns false.
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*/
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// bool empty() const { return tile_queue.empty(); }
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private:
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private:
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#ifdef ENABLE_THREADS
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/**
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* FIFO queue of tiles to load from data files.
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*/
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SGBlockingQueue< FGTileEntry* > tile_queue;
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#endif
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/**
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* Base name of directory containing tile data file.
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*/
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SGPath tile_path;
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#ifdef ENABLE_THREADS
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/**
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* Maximum number of threads to create for loading tiles.
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*/
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enum { MAX_THREADS = 1 };
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/**
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* This class represents the thread of execution responsible for
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* loading a tile.
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*/
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class LoaderThread : public SGThread
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{
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public:
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LoaderThread( FGTileLoader* l ) : loader(l) {}
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~LoaderThread() {}
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/**
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* Reads the tile from disk.
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*/
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void run();
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private:
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FGTileLoader* loader;
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private:
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// not implemented.
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LoaderThread();
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LoaderThread( const LoaderThread& );
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LoaderThread& operator=( const LoaderThread& );
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};
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friend class LoaderThread;
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/**
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* Array of loading threads.
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*/
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LoaderThread* threads[ MAX_THREADS ];
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/**
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* Lock and synchronize access to tile queue.
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*/
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SGMutex mutex;
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SGCondition frame_cond;
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/**
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* Thread cleanup handler.
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*/
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friend void cleanup_handler( void* );
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#endif // ENABLE_THREADS
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};
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#endif // FG_TILE_LOADER_HXX
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