comparison stk/include/ADSR.h @ 0:4606bd505630 tip

first import

+#ifndef STK_ADSR_H
+#define STK_ADSR_H
+
+#include "Generator.h"
+
+namespace stk {
+
+/***************************************************/
+/*! \class ADSR
+    \brief STK ADSR envelope class.
+
+    This class implements a traditional ADSR (Attack, Decay, Sustain,
+    Release) envelope.  It responds to simple keyOn and keyOff
+    messages, keeping track of its state.  The \e state = ADSR::IDLE
+    before being triggered and after the envelope value reaches 0.0 in
+    the ADSR::RELEASE state.  All rate, target and level settings must
+    be non-negative.  All time settings are in seconds and must be
+    positive.
+
+    by Perry R. Cook and Gary P. Scavone, 1995--2014.
+*/
+/***************************************************/
+
+class ADSR : public Generator
+{
+ public:
+
+  //! ADSR envelope states.
+  enum {
+    ATTACK,   /*!< Attack */
+    DECAY,    /*!< Decay */
+    SUSTAIN,  /*!< Sustain */
+    RELEASE,  /*!< Release */
+    IDLE      /*!< Before attack / after release */
+  };
+
+  //! Default constructor.
+  ADSR( void );
+
+  //! Class destructor.
+  ~ADSR( void );
+
+  //! Set target = 1, state = \e ADSR::ATTACK.
+  void keyOn( void );
+
+  //! Set target = 0, state = \e ADSR::RELEASE.
+  void keyOff( void );
+
+  //! Set the attack rate (gain / sample).
+  void setAttackRate( StkFloat rate );
+
+  //! Set the target value for the attack (default = 1.0).
+  void setAttackTarget( StkFloat target );
+
+  //! Set the decay rate (gain / sample).
+  void setDecayRate( StkFloat rate );
+
+  //! Set the sustain level.
+  void setSustainLevel( StkFloat level );
+
+  //! Set the release rate (gain / sample).
+  void setReleaseRate( StkFloat rate );
+
+  //! Set the attack rate based on a time duration (seconds).
+  void setAttackTime( StkFloat time );
+
+  //! Set the decay rate based on a time duration (seconds).
+  void setDecayTime( StkFloat time );
+
+  //! Set the release rate based on a time duration (seconds).
+  void setReleaseTime( StkFloat time );
+
+  //! Set sustain level and attack, decay, and release time durations (seconds).
+  void setAllTimes( StkFloat aTime, StkFloat dTime, StkFloat sLevel, StkFloat rTime );
+
+  //! Set a sustain target value and attack or decay from current value to target.
+  void setTarget( StkFloat target );
+
+  //! Return the current envelope \e state (ATTACK, DECAY, SUSTAIN, RELEASE, IDLE).
+  int getState( void ) const { return state_; };
+
+  //! Set to state = ADSR::SUSTAIN with current and target values of \e value.
+  void setValue( StkFloat value );
+
+  //! Return the last computed output value.
+  StkFloat lastOut( void ) const { return lastFrame_[0]; };
+
+  //! Compute and return one output sample.
+  StkFloat tick( void );
+
+  //! Fill a channel of the StkFrames object with computed outputs.
+  /*!
+    The \c channel argument must be less than the number of
+    channels in the StkFrames argument (the first channel is specified
+    by 0).  However, range checking is only performed if _STK_DEBUG_
+    is defined during compilation, in which case an out-of-range value
+    will trigger an StkError exception.
+  */
+  StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
+
+ protected:  
+
+  void sampleRateChanged( StkFloat newRate, StkFloat oldRate );
+
+  int state_;
+  StkFloat value_;
+  StkFloat target_;
+  StkFloat attackRate_;
+  StkFloat decayRate_;
+  StkFloat releaseRate_;
+  StkFloat releaseTime_;
+  StkFloat sustainLevel_;
+};
+
+inline StkFloat ADSR :: tick( void )
+{
+  switch ( state_ ) {
+
+  case ATTACK:
+    value_ += attackRate_;
+    if ( value_ >= target_ ) {
+      value_ = target_;
+      target_ = sustainLevel_;
+	    state_ = DECAY;
+    }
+    lastFrame_[0] = value_;
+    break;
+
+  case DECAY:
+    if ( value_ > sustainLevel_ ) {
+      value_ -= decayRate_;
+      if ( value_ <= sustainLevel_ ) {
+        value_ = sustainLevel_;
+        state_ = SUSTAIN;
+      }
+    }
+    else {
+      value_ += decayRate_; // attack target < sustain level
+      if ( value_ >= sustainLevel_ ) {
+        value_ = sustainLevel_;
+        state_ = SUSTAIN;
+      }
+    }
+    lastFrame_[0] = value_;
+    break;
+
+  case RELEASE:
+    value_ -= releaseRate_;
+    if ( value_ <= 0.0 ) {
+      value_ = 0.0;
+      state_ = IDLE;
+    }
+    lastFrame_[0] = value_;
+
+  }
+
+  return value_;
+}
+
+inline StkFrames& ADSR :: tick( StkFrames& frames, unsigned int channel )
+{
+#if defined(_STK_DEBUG_)
+  if ( channel >= frames.channels() ) {
+    oStream_ << "ADSR::tick(): channel and StkFrames arguments are incompatible!";
+    handleError( StkError::FUNCTION_ARGUMENT );
+  }
+#endif
+
+  StkFloat *samples = &frames[channel];
+  unsigned int hop = frames.channels();
+  for ( unsigned int i=0; i<frames.frames(); i++, samples += hop )
+    *samples = ADSR::tick();
+
+  return frames;
+}
+
+} // stk namespace
+
+#endif