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split out PolyphaseFilterCache::GetPolyphaseFilter

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This commit is contained in:
Glenn Maynard
2006-11-28 21:32:07 +00:00
parent 0d7f657453
commit bdffe5713e
1 changed files with 38 additions and 31 deletions
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stepmania/src/RageSoundReader_Resample_Good.cpp
+38 -31
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@@ -394,6 +394,43 @@ int PolyphaseFilter::NumInputsForOutputSamples( const State &State, int iOut, in
return iIn; return iIn;
} }
namespace PolyphaseFilterCache
{
/* Cache filter data, and reuse it without copying. All operations after creation
* are const, so this doesn't cause thread-safety problems. */
typedef map<pair<int,float>, PolyphaseFilter *> FilterMap;
static RageMutex PolyphaseFiltersLock("PolyphaseFiltersLock");
static FilterMap g_mapPolyphaseFilters;
const PolyphaseFilter *GetPolyphaseFilter( int iUpFactor, float fCutoffFrequency )
{
PolyphaseFiltersLock.Lock();
pair<int,float> params( make_pair(iUpFactor, fCutoffFrequency) );
FilterMap::const_iterator it = g_mapPolyphaseFilters.find(params);
if( it != g_mapPolyphaseFilters.end() )
{
/* We already have a filter for this upsampling factor and cutoff; use it. */
PolyphaseFilter *pPolyphase = it->second;
PolyphaseFiltersLock.Unlock();
return pPolyphase;
}
int iWinSize = L*iUpFactor;
float *pFIR = new float[iWinSize];
GenerateSincLowPassFilter( pFIR, iWinSize, fCutoffFrequency );
ApplyKaiserWindow( pFIR, iWinSize, 8 );
NormalizeVector( pFIR, iWinSize );
MultiplyVector( &pFIR[0], &pFIR[iWinSize], (float) iUpFactor );
PolyphaseFilter *pPolyphase = new PolyphaseFilter( iUpFactor );
pPolyphase->Generate( pFIR );
delete [] pFIR;
g_mapPolyphaseFilters[params] = pPolyphase;
PolyphaseFiltersLock.Unlock();
return pPolyphase;
}
}
/* /*
* Interface to PolyphaseFilter, providing a simple resampling interface. This handles * Interface to PolyphaseFilter, providing a simple resampling interface. This handles
* reuse of PolyphaseFilters. This does not handle delay, flushing, or multiple channels. * reuse of PolyphaseFilters. This does not handle delay, flushing, or multiple channels.
@@ -426,37 +463,7 @@ public:
LOG->Trace( "cutoff frequency %f -> %f, %f", fCutoffFrequency, 1.0f / (2*iUpFactor), 1.0f / (2*m_iDownFactor) ); LOG->Trace( "cutoff frequency %f -> %f, %f", fCutoffFrequency, 1.0f / (2*iUpFactor), 1.0f / (2*m_iDownFactor) );
} }
/* Cache filter data, and reuse it without copying. All operations after creation m_pPolyphase = PolyphaseFilterCache::GetPolyphaseFilter( iUpFactor, fCutoffFrequency );
* are const, so this doesn't cause thread-safety problems. */
typedef map<pair<int,float>, PolyphaseFilter *> FilterMap;
static RageMutex PolyphaseFiltersLock("PolyphaseFiltersLock");
static FilterMap g_mapPolyphaseFilters;
PolyphaseFiltersLock.Lock();
pair<int,float> params( make_pair(iUpFactor, fCutoffFrequency) );
FilterMap::const_iterator it = g_mapPolyphaseFilters.find(params);
if( it == g_mapPolyphaseFilters.end() )
{
int iWinSize = L*iUpFactor;
float *pFIR = new float[iWinSize];
GenerateSincLowPassFilter( pFIR, iWinSize, fCutoffFrequency );
ApplyKaiserWindow( pFIR, iWinSize, 8 );
NormalizeVector( pFIR, iWinSize );
MultiplyVector( &pFIR[0], &pFIR[iWinSize], (float) iUpFactor );
PolyphaseFilter *pPolyphase = new PolyphaseFilter( iUpFactor );
pPolyphase->Generate( pFIR );
delete [] pFIR;
g_mapPolyphaseFilters[params] = pPolyphase;
m_pPolyphase = pPolyphase;
}
else
{
/* We already have a filter for this upsampling factor and cutoff; use it. */
m_pPolyphase = it->second;
}
PolyphaseFiltersLock.Unlock();
m_pState = new PolyphaseFilter::State( *m_pPolyphase ); m_pState = new PolyphaseFilter::State( *m_pPolyphase );
} }