Work on Voice state

lib/Envelope.cpp

@@ -0,0 +1,73 @@
+#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:
+    {
+        double attackFac = m_curMs / (m_curADSR->attackCoarse * 255 + m_curADSR->attackFine);
+        if (attackFac >= 1.0)
+        {
+            m_phase = State::Decay;
+            m_curMs = 0;
+            return 1.f;
+        }
+        m_releaseStartFactor = attackFac;
+        return attackFac;
+    }
+    case State::Decay:
+    {
+        double decayFac = m_curMs / (m_curADSR->decayCoarse * 255 + m_curADSR->decayFine);
+        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:
+    {
+        double releaseFac = m_curMs / (m_curADSR->releaseCoarse * 255 + m_curADSR->releaseFine);
+        if (releaseFac >= 1.0)
+            return 0.f;
+        return (1.0 - releaseFac) * m_releaseStartFactor;
+    }
+    }
+}
+
+}