Version 4.2.1

src/SineWave.cpp

@@ -0,0 +1,103 @@
+/***************************************************/
+/*! \class SineWave
+    \brief STK sinusoid oscillator class.
+
+    This class computes and saves a static sine "table" that can be
+    shared by multiple instances.  It has an interface similar to the
+    WaveLoop class but inherits from the Generator class.  Output
+    values are computed using linear interpolation.
+
+    The "table" length, set in SineWave.h, is 2048 samples by default.
+
+    by Perry R. Cook and Gary P. Scavone, 1995 - 2005.
+*/
+/***************************************************/
+
+#include "SineWave.h"
+#include <cmath>
+
+StkFrames SineWave :: table_;
+
+SineWave :: SineWave( void )
+  : time_(0.0), rate_(1.0), phaseOffset_(0.0)
+{
+  if ( table_.empty() ) {
+    table_.resize( TABLE_SIZE + 1, 1 );
+    StkFloat temp = 1.0 / TABLE_SIZE;
+    for ( unsigned long i=0; i<=TABLE_SIZE; i++ )
+      table_[i] = sin( TWO_PI * i * temp );
+  }
+}
+
+SineWave :: ~SineWave()
+{
+}
+
+void SineWave :: reset(void)
+{
+  time_ = 0.0;
+  lastOutput_ = 0;
+}
+
+void SineWave :: setFrequency( StkFloat frequency )
+{
+  // This is a looping frequency.
+  this->setRate( TABLE_SIZE * frequency / Stk::sampleRate() );
+}
+
+void SineWave :: addTime( StkFloat time )
+{
+  // Add an absolute time in samples.
+  time_ += time;
+
+  while ( time_ < 0.0 )
+    time_ += TABLE_SIZE;
+  while ( time_ >= TABLE_SIZE )
+    time_ -= TABLE_SIZE;
+}
+
+void SineWave :: addPhase( StkFloat angle )
+{
+  // Add a time in cycles (one cycle = TABLE_SIZE).
+  time_ += TABLE_SIZE * angle;
+
+  while ( time_ < 0.0 )
+    time_ += TABLE_SIZE;
+  while ( time_ >= TABLE_SIZE )
+    time_ -= TABLE_SIZE;
+}
+
+void SineWave :: addPhaseOffset( StkFloat angle )
+{
+  // Add a phase offset in cycles, where 1.0 = TABLE_SIZE.
+  phaseOffset_ = TABLE_SIZE * angle;
+}
+
+StkFloat SineWave :: computeSample( void )
+{
+  // Check limits of time address ... if necessary, recalculate modulo
+  // TABLE_SIZE.
+  while ( time_ < 0.0 )
+    time_ += TABLE_SIZE;
+  while ( time_ >= TABLE_SIZE )
+    time_ -= TABLE_SIZE;
+
+  StkFloat tyme;
+  if ( phaseOffset_ ) {
+    tyme = time_ + phaseOffset_;
+    while ( tyme < 0.0 )
+      tyme += TABLE_SIZE;
+    while ( tyme >= TABLE_SIZE )
+      tyme -= TABLE_SIZE;
+  }
+  else {
+    tyme = time_;
+  }
+
+  lastOutput_ = table_.interpolate( tyme );
+
+  // Increment time, which can be negative.
+  time_ += rate_;
+
+  return lastOutput_;
+}