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https://github.com/cookiengineer/audacity
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126 lines
2.3 KiB
C++
126 lines
2.3 KiB
C++
/***************************************************/
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/*! \class Envelope
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\brief STK envelope base class.
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This class implements a simple envelope
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generator which is capable of ramping to
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a target value by a specified \e rate.
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It also responds to simple \e keyOn and
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\e keyOff messages, ramping to 1.0 on
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keyOn and to 0.0 on keyOff.
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by Perry R. Cook and Gary P. Scavone, 1995 - 2005.
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*/
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/***************************************************/
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#include "Envelope.h"
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using namespace Nyq;
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Envelope :: Envelope(void) : Generator()
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{
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target_ = 0.0;
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value_ = 0.0;
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rate_ = 0.001;
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state_ = 0;
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}
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Envelope :: Envelope ( const Envelope& e )
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{
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target_ = 0.0;
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value_ = 0.0;
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rate_ = 0.001;
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state_ = 0;
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}
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Envelope :: ~Envelope(void)
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{
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}
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Envelope& Envelope :: operator= ( const Envelope& e )
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{
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if ( this != &e ) {
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target_ = e.target_;
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value_ = e.value_;
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rate_ = e.rate_;
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state_ = e.state_;
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}
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return *this;
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}
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void Envelope :: keyOn(void)
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{
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target_ = 1.0;
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if (value_ != target_) state_ = 1;
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}
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void Envelope :: keyOff(void)
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{
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target_ = 0.0;
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if (value_ != target_) state_ = 1;
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}
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void Envelope :: setRate(StkFloat rate)
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{
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if (rate < 0.0) {
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errorString_ << "Envelope::setRate: negative rates not allowed ... correcting!";
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handleError( StkError::WARNING );
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rate_ = -rate;
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}
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else
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rate_ = rate;
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}
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void Envelope :: setTime(StkFloat time)
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{
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if (time < 0.0) {
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errorString_ << "Envelope::setTime: negative times not allowed ... correcting!";
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handleError( StkError::WARNING );
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rate_ = 1.0 / (-time * Stk::sampleRate());
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}
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else
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rate_ = 1.0 / (time * Stk::sampleRate());
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}
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void Envelope :: setTarget(StkFloat target)
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{
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target_ = target;
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if (value_ != target_) state_ = 1;
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}
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void Envelope :: setValue(StkFloat value)
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{
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state_ = 0;
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target_ = value;
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value_ = value;
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}
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int Envelope :: getState(void) const
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{
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return state_;
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}
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StkFloat Envelope :: computeSample(void )
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{
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if (state_) {
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if (target_ > value_) {
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value_ += rate_;
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if (value_ >= target_) {
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value_ = target_;
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state_ = 0;
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}
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}
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else {
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value_ -= rate_;
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if (value_ <= target_) {
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value_ = target_;
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state_ = 0;
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}
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}
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}
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lastOutput_ = value_;
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return value_;
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}
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