blender/intern/audaspace/FX/AUD_EnvelopeFactory.cpp
Joerg Mueller 52ef66da4d Audaspace:
* Created awesome filter classes :)
* Made all filter effects use the filter classes instead of having the same implementation everywhere.
* Added a Python API for LTI IIR filters.
* Fixed a warning in creator.c that was introduced when adding game autoplay.
2010-08-01 22:33:50 +00:00

79 lines
2.2 KiB
C++

/*
* $Id$
*
* ***** BEGIN LGPL LICENSE BLOCK *****
*
* Copyright 2009 Jörg Hermann Müller
*
* This file is part of AudaSpace.
*
* AudaSpace is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* AudaSpace is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with AudaSpace. If not, see <http://www.gnu.org/licenses/>.
*
* ***** END LGPL LICENSE BLOCK *****
*/
#include "AUD_EnvelopeFactory.h"
#include "AUD_CallbackIIRFilterReader.h"
#include <cmath>
struct EnvelopeParameters
{
float attack;
float release;
float threshold;
float arthreshold;
};
sample_t envelopeFilter(AUD_CallbackIIRFilterReader* reader, EnvelopeParameters* param)
{
float in = fabs(reader->x(0));
float out = reader->y(-1);
if(in < param->threshold)
in = 0.0f;
return (in > out ? param->attack : param->release) * (out - in) + in;
}
void endEnvelopeFilter(EnvelopeParameters* param)
{
delete param;
}
AUD_EnvelopeFactory::AUD_EnvelopeFactory(AUD_IFactory* factory, float attack,
float release, float threshold,
float arthreshold) :
AUD_EffectFactory(factory),
m_attack(attack),
m_release(release),
m_threshold(threshold),
m_arthreshold(arthreshold)
{
}
AUD_IReader* AUD_EnvelopeFactory::createReader() const
{
AUD_IReader* reader = getReader();
EnvelopeParameters* param = new EnvelopeParameters();
param->arthreshold = m_arthreshold;
param->attack = pow(m_arthreshold, 1.0f/(reader->getSpecs().rate * m_attack));
param->release = pow(m_arthreshold, 1.0f/(reader->getSpecs().rate * m_release));
param->threshold = m_threshold;
return new AUD_CallbackIIRFilterReader(reader, 1, 2,
(doFilterIIR) envelopeFilter,
(endFilterIIR) endEnvelopeFilter,
param);
}