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flightgear/src/Scenery/newcache.cxx

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C++

// newcache.cxx -- routines to handle scenery tile caching
//
// Written by Curtis Olson, started December 2000.
//
// Copyright (C) 2000 Curtis L. Olson - curt@flightgear.org
//
// 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
#ifdef HAVE_WINDOWS_H
# include <windows.h>
#endif
#include <GL/glut.h>
#include <GL/gl.h>
#include <plib/ssg.h> // plib include
#include <simgear/bucket/newbucket.hxx>
#include <simgear/debug/logstream.hxx>
#include <simgear/misc/sg_path.hxx>
#include <Main/globals.hxx>
#include <Main/viewer.hxx>
#include <Scenery/scenery.hxx> // for scenery.center
#include "newcache.hxx"
#include "tileentry.hxx"
SG_USING_NAMESPACE(std);
// Constructor
FGNewCache::FGNewCache( void ) :
max_cache_size(100)
{
tile_cache.clear();
}
// Destructor
FGNewCache::~FGNewCache( void ) {
}
// Free a tile cache entry
void FGNewCache::entry_free( long cache_index ) {
SG_LOG( SG_TERRAIN, SG_DEBUG, "FREEING CACHE ENTRY = " << cache_index );
FGTileEntry *tile = tile_cache[cache_index];
tile->disconnect_ssg_nodes();
#ifdef WISH_PLIB_WAS_THREADED // but it isn't
tile->sched_removal();
#else
tile->free_tile();
delete tile;
#endif
tile_cache.erase( cache_index );
}
// Initialize the tile cache subsystem
void FGNewCache::init( void ) {
SG_LOG( SG_TERRAIN, SG_INFO, "Initializing the tile cache." );
SG_LOG( SG_TERRAIN, SG_INFO, " max cache size = "
<< max_cache_size );
SG_LOG( SG_TERRAIN, SG_INFO, " current cache size = "
<< tile_cache.size() );
#if 0 // don't clear the cache
clear_cache();
#endif
SG_LOG( SG_TERRAIN, SG_INFO, " done with init()" );
}
// Search for the specified "bucket" in the cache
bool FGNewCache::exists( const SGBucket& b ) const {
long tile_index = b.gen_index();
const_tile_map_iterator it = tile_cache.find( tile_index );
return ( it != tile_cache.end() );
}
#if 0
// Ensure at least one entry is free in the cache
bool FGNewCache::make_space() {
SG_LOG( SG_TERRAIN, SG_DEBUG, "Make space in cache" );
SG_LOG( SG_TERRAIN, SG_DEBUG, "cache entries = " << tile_cache.size() );
SG_LOG( SG_TERRAIN, SG_DEBUG, "max size = " << max_cache_size );
if ( (int)tile_cache.size() < max_cache_size ) {
// space in the cache, return
return true;
}
while ( (int)tile_cache.size() >= max_cache_size ) {
sgdVec3 abs_view_pos;
float dist;
double timestamp = 0.0;
int max_index = -1;
double min_time = 2419200000.0f; // one month should be enough
double max_time = 0;
// we need to free the furthest entry
tile_map_iterator current = tile_cache.begin();
tile_map_iterator end = tile_cache.end();
for ( ; current != end; ++current ) {
long index = current->first;
FGTileEntry *e = current->second;
if ( e->is_loaded() && (e->get_pending_models() == 0) ) {
timestamp = e->get_timestamp();
if ( timestamp < min_time ) {
max_index = index;
min_time = timestamp;
}
if ( timestamp > max_time ) {
max_time = timestamp;
}
} else {
SG_LOG( SG_TERRAIN, SG_DEBUG, "loaded = " << e->is_loaded()
<< " pending models = " << e->get_pending_models()
<< " time stamp = " << e->get_timestamp() );
}
}
// If we made it this far, then there were no open cache entries.
// We will instead free the oldest cache entry and return true
SG_LOG( SG_TERRAIN, SG_DEBUG, " min_time = " << min_time );
SG_LOG( SG_TERRAIN, SG_DEBUG, " index = " << max_index );
SG_LOG( SG_TERRAIN, SG_DEBUG, " max_time = " << max_time );
if ( max_index >= 0 ) {
entry_free( max_index );
return true;
} else {
SG_LOG( SG_TERRAIN, SG_ALERT, "WHOOPS!!! can't make_space(), tile "
"cache is full, but no entries available for removal." );
return false;
}
}
SG_LOG( SG_TERRAIN, SG_ALERT, "WHOOPS!!! Hit an unhandled condition in "
"FGNewCache::make_space()." );
return false;
}
#endif
// Return the index of the oldest tile in the cache, return -1 if
// nothing available to be removed.
long FGNewCache::get_oldest_tile() {
// we need to free the furthest entry
long min_index = -1;
double timestamp = 0.0;
double min_time = 2419200000.0f; // one month should be enough
double max_time = 0;
tile_map_iterator current = tile_cache.begin();
tile_map_iterator end = tile_cache.end();
for ( ; current != end; ++current ) {
long index = current->first;
FGTileEntry *e = current->second;
if ( e->is_loaded() && (e->get_pending_models() == 0) ) {
timestamp = e->get_timestamp();
if ( timestamp < min_time ) {
min_index = index;
min_time = timestamp;
}
if ( timestamp > max_time ) {
max_time = timestamp;
}
} else {
SG_LOG( SG_TERRAIN, SG_DEBUG, "loaded = " << e->is_loaded()
<< " pending models = " << e->get_pending_models()
<< " time stamp = " << e->get_timestamp() );
}
}
SG_LOG( SG_TERRAIN, SG_DEBUG, " min_time = " << min_time );
SG_LOG( SG_TERRAIN, SG_DEBUG, " index = " << min_index );
SG_LOG( SG_TERRAIN, SG_DEBUG, " max_time = " << max_time );
return min_index;
}
// Clear a cache entry, note that the cache only holds pointers
// and this does not free the object which is pointed to.
void FGNewCache::clear_entry( long cache_index ) {
tile_cache.erase( cache_index );
}
// Clear all completely loaded tiles (ignores partially loaded tiles)
void FGNewCache::clear_cache() {
tile_map_iterator current = tile_cache.begin();
tile_map_iterator end = tile_cache.end();
for ( ; current != end; ++current ) {
long index = current->first;
SG_LOG( SG_TERRAIN, SG_DEBUG, "clearing " << index );
FGTileEntry *e = current->second;
if ( e->is_loaded() && (e->get_pending_models() == 0) ) {
e->tile_bucket.make_bad();
entry_free(index);
}
}
// and ... just in case we missed something ...
globals->get_scenery()->get_terrain_branch()->removeAllKids();
}
/**
* Create a new tile and schedule it for loading.
*/
bool FGNewCache::insert_tile( FGTileEntry *e ) {
// set time of insertion for tracking age of tiles...
e->set_timestamp(globals->get_sim_time_sec());
// register it in the cache
long tile_index = e->get_tile_bucket().gen_index();
tile_cache[tile_index] = e;
return true;
}
// Note this is the old version of FGNewCache::make_space(), currently disabled
// It uses distance from a center point to determine tiles to be discarded...
#if 0
// Ensure at least one entry is free in the cache
bool FGNewCache::make_space() {
SG_LOG( SG_TERRAIN, SG_DEBUG, "Make space in cache" );
SG_LOG( SG_TERRAIN, SG_DEBUG, "cache entries = " << tile_cache.size() );
SG_LOG( SG_TERRAIN, SG_DEBUG, "max size = " << max_cache_size );
if ( (int)tile_cache.size() < max_cache_size ) {
// space in the cache, return
return true;
}
while ( (int)tile_cache.size() >= max_cache_size ) {
sgdVec3 abs_view_pos;
float dist;
float max_dist = 0.0;
int max_index = -1;
// we need to free the furthest entry
tile_map_iterator current = tile_cache.begin();
tile_map_iterator end = tile_cache.end();
for ( ; current != end; ++current ) {
long index = current->first;
FGTileEntry *e = current->second;
if ( e->is_loaded() && (e->get_pending_models() == 0) ) {
// calculate approximate distance from view point
sgdCopyVec3( abs_view_pos,
globals->get_current_view()->get_absolute_view_pos() );
SG_LOG( SG_TERRAIN, SG_DEBUG, "DIST Abs view pos = "
<< abs_view_pos[0] << ","
<< abs_view_pos[1] << ","
<< abs_view_pos[2] );
SG_LOG( SG_TERRAIN, SG_DEBUG,
" ref point = " << e->center );
sgdVec3 center;
sgdSetVec3( center,
e->center.x(), e->center.y(), e->center.z() );
dist = sgdDistanceVec3( center, abs_view_pos );
SG_LOG( SG_TERRAIN, SG_DEBUG, " distance = " << dist );
if ( dist > max_dist ) {
max_dist = dist;
max_index = index;
}
} else {
SG_LOG( SG_TERRAIN, SG_INFO, "loaded = " << e->is_loaded()
<< " pending models = " << e->get_pending_models() );
}
}
// If we made it this far, then there were no open cache entries.
// We will instead free the furthest cache entry and return true
SG_LOG( SG_TERRAIN, SG_INFO, " max_dist = " << max_dist );
SG_LOG( SG_TERRAIN, SG_INFO, " index = " << max_index );
if ( max_index >= 0 ) {
entry_free( max_index );
return true;
} else {
SG_LOG( SG_TERRAIN, SG_ALERT, "WHOOPS!!! can't make_space(), tile "
"cache is full, but no entries available for removal." );
return false;
}
}
SG_LOG( SG_TERRAIN, SG_ALERT, "WHOOPS!!! Hit an unhandled condition in "
"FGNewCache::make_space()." );
return false;
}
#endif