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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/FaderReader.h"
#include <cstring>
AUD_NAMESPACE_BEGIN
FaderReader::FaderReader(std::shared_ptr<IReader> reader, FadeType type, double start, double length) :
EffectReader(reader),
m_type(type),
m_start(start),
m_length(length)
{
}
void FaderReader::read(int& length, bool& eos, sample_t* buffer)
{
int position = m_reader->getPosition();
Specs specs = m_reader->getSpecs();
int samplesize = AUD_SAMPLE_SIZE(specs);
m_reader->read(length, eos, buffer);
if((position + length) / specs.rate <= m_start)
{
if(m_type != FADE_OUT)
{
std::memset(buffer, 0, length * samplesize);
}
}
else if(position / specs.rate >= m_start+m_length)
{
if(m_type == FADE_OUT)
{
std::memset(buffer, 0, length * samplesize);
}
}
else
{
float volume = 1.0f;
for(int i = 0; i < length * specs.channels; i++)
{
if(i % specs.channels == 0)
{
volume = float((((position + i) / specs.rate) - m_start) / m_length);
if(volume > 1.0f)
volume = 1.0f;
else if(volume < 0.0f)
volume = 0.0f;
if(m_type == FADE_OUT)
volume = 1.0f - volume;
}
buffer[i] = buffer[i] * volume;
}
}
}
AUD_NAMESPACE_END
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