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/*******************************************************************************
* Copyright 2009-2016 Jörg Müller
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
******************************************************************************/
#include "fx/ADSRReader.h"
AUD_NAMESPACE_BEGIN
ADSRReader::ADSRReader(std::shared_ptr<IReader> reader, float attack, float decay, float sustain, float release) :
EffectReader(reader),
m_attack(attack), m_decay(decay), m_sustain(sustain), m_release(release)
{
nextState(ADSR_STATE_ATTACK);
}
ADSRReader::~ADSRReader()
{
}
void ADSRReader::nextState(ADSRState state)
{
m_state = state;
switch(m_state)
{
case ADSR_STATE_ATTACK:
m_level = 0;
if(m_attack <= 0)
{
nextState(ADSR_STATE_DECAY);
return;
}
return;
case ADSR_STATE_DECAY:
if(m_decay <= 0)
{
nextState(ADSR_STATE_SUSTAIN);
return;
}
if(m_level > 1.0)
m_level = 1 - (m_level - 1) * m_attack / m_decay * (1 - m_sustain);
if(m_level <= m_sustain)
nextState(ADSR_STATE_SUSTAIN);
break;
case ADSR_STATE_SUSTAIN:
m_level = m_sustain;
break;
case ADSR_STATE_RELEASE:
if(m_release <= 0)
{
nextState(ADSR_STATE_INVALID);
return;
}
break;
case ADSR_STATE_INVALID:
break;
}
}
void ADSRReader::read(int & length, bool &eos, sample_t* buffer)
{
Specs specs = m_reader->getSpecs();
m_reader->read(length, eos, buffer);
for(int i = 0; i < length; i++)
{
for(int channel = 0; channel < specs.channels; channel++)
{
buffer[i * specs.channels + channel] *= m_level;
}
switch(m_state)
{
case ADSR_STATE_ATTACK:
m_level += 1 / m_attack / specs.rate;
if(m_level >= 1)
nextState(ADSR_STATE_DECAY);
break;
case ADSR_STATE_DECAY:
m_level -= (1 - m_sustain) / m_decay / specs.rate;
if(m_level <= m_sustain)
nextState(ADSR_STATE_SUSTAIN);
break;
case ADSR_STATE_SUSTAIN:
break;
case ADSR_STATE_RELEASE:
m_level -= m_sustain / m_release / specs.rate ;
if(m_level <= 0)
nextState(ADSR_STATE_INVALID);
break;
case ADSR_STATE_INVALID:
length = i;
return;
}
}
}
void ADSRReader::release()
{
nextState(ADSR_STATE_RELEASE);
}
AUD_NAMESPACE_END
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