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Version 4.4.0

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This commit is contained in:
Gary Scavone
2013-09-29 23:11:39 +02:00
committed by Stephen Sinclair
parent d199342e86
commit eccd8c9981
287 changed files with 11712 additions and 7676 deletions
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48
src/BlitSquare.cpp
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@@ -25,14 +25,14 @@
Blit waveforms. This class is not guaranteed to be well behaved
in the presence of significant aliasing.
Based on initial code of Robin Davies, 2005.
Modified algorithm code by Gary Scavone, 2005 - 2006.
Based on initial code of Robin Davies, 2005
Modified algorithm code by Gary Scavone, 2005 - 2009.
*/
/***************************************************/
#include "BlitSquare.h"
#include <cmath>
#include <limits>
namespace stk {
BlitSquare:: BlitSquare( StkFloat frequency )
{
@@ -48,7 +48,7 @@ BlitSquare :: ~BlitSquare()
void BlitSquare :: reset()
{
phase_ = 0.0;
lastOutput_ = 0;
lastFrame_[0] = 0.0;
dcbState_ = 0.0;
lastBlitOutput_ = 0;
}
@@ -92,40 +92,4 @@ void BlitSquare :: updateHarmonics( void )
#endif
}
StkFloat BlitSquare :: computeSample( void )
{
StkFloat temp = lastBlitOutput_;
// A fully optimized version of this would replace the two sin calls
// with a pair of fast sin oscillators, for which stable fast
// two-multiply algorithms are well known. In the spirit of STK,
// which favors clarity over performance, the optimization has
// not been made here.
// Avoid a divide by zero, or use of a denomralized divisor
// at the sinc peak, which has a limiting value of 1.0.
StkFloat denominator = sin( phase_ );
if ( fabs( denominator ) < std::numeric_limits<StkFloat>::epsilon() ) {
// Inexact comparison safely distinguishes betwen *close to zero*, and *close to PI*.
if ( phase_ < 0.1f || phase_ > TWO_PI - 0.1f )
lastBlitOutput_ = a_;
else
lastBlitOutput_ = -a_;
}
else {
lastBlitOutput_ = sin( m_ * phase_ );
lastBlitOutput_ /= p_ * denominator;
}
lastBlitOutput_ += temp;
// Now apply DC blocker.
lastOutput_ = lastBlitOutput_ - dcbState_ + 0.999 * lastOutput_;
dcbState_ = lastBlitOutput_;
phase_ += rate_;
if ( phase_ >= TWO_PI ) phase_ -= TWO_PI;
return lastOutput_;
}
} // stk namespace