amuse/lib/Envelope.cpp

92 lines
2.1 KiB
C++

#include "amuse/Envelope.hpp"
namespace amuse
{
void Envelope::reset(const ADSR* adsr)
{
m_phase = State::Attack;
m_curADSR = adsr;
m_curMs = 0;
m_sustainFactor = (adsr->sustainCoarse * 6.25 + adsr->sustainFine * 0.0244) / 100.0;
m_releaseStartFactor = 0.0;
}
void Envelope::keyOff()
{
m_phase = State::Release;
m_curMs = 0;
}
float Envelope::nextSample(double sampleRate)
{
if (!m_curADSR)
{
if (m_phase == State::Release)
return 0.f;
return 1.f;
}
m_curMs += 1.0 / (sampleRate / 1000.0);
switch (m_phase)
{
case State::Attack:
{
uint16_t attack = m_curADSR->attackCoarse * 255 + m_curADSR->attackFine;
if (attack == 0)
{
m_phase = State::Decay;
m_curMs = 0;
return 1.f;
}
double attackFac = m_curMs / double(attack);
if (attackFac >= 1.0)
{
m_phase = State::Decay;
m_curMs = 0;
return 1.f;
}
m_releaseStartFactor = attackFac;
return attackFac;
}
case State::Decay:
{
uint16_t decay = m_curADSR->decayCoarse * 255 + m_curADSR->decayFine;
if (decay == 0)
{
m_phase = State::Sustain;
m_curMs = 0;
m_releaseStartFactor = m_sustainFactor;
return m_sustainFactor;
}
double decayFac = m_curMs / double(decay);
if (decayFac >= 1.0)
{
m_phase = State::Sustain;
m_curMs = 0;
m_releaseStartFactor = m_sustainFactor;
return m_sustainFactor;
}
m_releaseStartFactor = (1.0 - decayFac) + decayFac * m_sustainFactor;
return m_releaseStartFactor;
}
case State::Sustain:
{
return m_sustainFactor;
}
case State::Release:
{
uint16_t release = m_curADSR->releaseCoarse * 255 + m_curADSR->releaseFine;
if (release == 0)
return 0.f;
double releaseFac = m_curMs / double(release);
if (releaseFac >= 1.0)
return 0.f;
return (1.0 - releaseFac) * m_releaseStartFactor;
}
}
}
}