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Bugfix: wrong interpolation of winds aloft

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Fix a bug reported by Jacob Burbach.
Environment interpolation did not work above layer 1
A potential division by zero is also included
This commit is contained in:
Torsten Dreyer 2010-07-17 18:49:31 +02:00
parent c95a5db23d
commit 8a1223ab27
1 changed files with 29 additions and 26 deletions
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45
src/Environment/environment_ctrl.cxx
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@ -183,6 +183,14 @@ FGInterpolateEnvironmentCtrl::read_table (const SGPropertyNode * node, vector<bu
if( sort_required )
sort(table.begin(), table.end(), bucket::lessThan);
// cleanup entries with (almost)same altitude
for( vector<bucket *>::size_type n = 1; n < table.size(); n++ ) {
if( fabs(table[n]->altitude_ft - table[n-1]->altitude_ft ) < 1 ) {
SG_LOG( SG_GENERAL, SG_ALERT, "Removing duplicate altitude entry in environment config for altitude " << table[n]->altitude_ft );
table.erase( table.begin() + n );
}
}
}
void
@ -207,8 +215,8 @@ FGInterpolateEnvironmentCtrl::update (double delta_time_sec)
// both tables
do_interpolate(_boundary_table, altitude_agl_ft, &env1);
do_interpolate(_aloft_table, altitude_ft, &env2);
double fraction =
(altitude_agl_ft - boundary_limit) / boundary_transition;
double fraction = boundary_transition > SGLimitsd::min() ?
(altitude_agl_ft - boundary_limit) / boundary_transition : 1.0;
interpolate(&env1, &env2, fraction, _environment);
return;
}
@ -226,29 +234,24 @@ FGInterpolateEnvironmentCtrl::do_interpolate (vector<bucket *> &table, double al
// Boundary conditions
if ((length == 1) || (table[0]->altitude_ft >= altitude_ft)) {
environment->copy(table[0]->environment);
environment->copy(table[0]->environment); // below bottom of table
return;
} else if (table[length-1]->altitude_ft <= altitude_ft) {
environment->copy(table[length-1]->environment);
environment->copy(table[length-1]->environment); // above top of table
return;
}
// Search the interpolation table
for (int i = 0; i < length - 1; i++) {
if ((i == length - 1) || (table[i]->altitude_ft <= altitude_ft)) {
FGEnvironment * env1 = &(table[i]->environment);
FGEnvironment * env2 = &(table[i+1]->environment);
double fraction;
if (table[i]->altitude_ft == table[i+1]->altitude_ft)
fraction = 1.0;
else
fraction =
((altitude_ft - table[i]->altitude_ft) /
(table[i+1]->altitude_ft - table[i]->altitude_ft));
interpolate(env1, env2, fraction, environment);
return;
}
}
// Search the interpolation table
int layer;
for ( layer = 1; // can't be below bottom layer, handled above
layer < length && table[layer]->altitude_ft <= altitude_ft;
layer++);
FGEnvironment * env1 = &(table[layer-1]->environment);
FGEnvironment * env2 = &(table[layer]->environment);
// two layers of same altitude were sorted out in read_table
double fraction = ((altitude_ft - table[layer-1]->altitude_ft) /
(table[layer]->altitude_ft - table[layer-1]->altitude_ft));
interpolate(env1, env2, fraction, environment);
}
bool
@ -747,7 +750,7 @@ void FGMetarCtrl::set_metar( const char * metar_string )
m = new FGMetar( metar_string );
}
catch( sg_io_exception ) {
fprintf( stderr, "can't get metar: %s\n", metar_string );
SG_LOG( SG_GENERAL, SG_WARN, "Can't get metar: " << metar_string );
metar_valid = false;
return;
}