From fbafa397fe9faadfc6f6c8b434e4f385bea4eac8 Mon Sep 17 00:00:00 2001
From: Jack Andersen <jackoalan@gmail.com>
Date: Sat, 21 May 2016 13:41:45 -1000
Subject: [PATCH] Use -10dB RMS formula for amplitude computation

---
 driver/main.cpp            | 2 +-
 include/amuse/Envelope.hpp | 4 ++--
 lib/SongState.cpp          | 8 ++++----
 lib/Voice.cpp              | 3 ++-
 4 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/driver/main.cpp b/driver/main.cpp
index 8af02f5..d09be62 100644
--- a/driver/main.cpp
+++ b/driver/main.cpp
@@ -191,7 +191,7 @@ struct AppCallback : boo::IApplicationCallback
     int8_t m_lastChanProg = -1;
 
     /* Control state */
-    float m_volume = 0.5f;
+    float m_volume = 0.8f;
     float m_modulation = 0.f;
     float m_pitchBend = 0.f;
     bool m_updateDisp = false;
diff --git a/include/amuse/Envelope.hpp b/include/amuse/Envelope.hpp
index aa71862..4c26b6e 100644
--- a/include/amuse/Envelope.hpp
+++ b/include/amuse/Envelope.hpp
@@ -20,10 +20,10 @@ public:
     };
 private:
     State m_phase = State::Attack; /**< Current envelope state */
-    double m_attackTime = 0.01; /**< Time of attack in seconds */
+    double m_attackTime = 0.005; /**< Time of attack in seconds */
     double m_decayTime = 0.0; /**< Time of decay in seconds */
     double m_sustainFactor = 1.0; /**< Evaluated sustain percentage */
-    double m_releaseTime = 0.01; /**< Time of release in seconds */
+    double m_releaseTime = 0.005; /**< Time of release in seconds */
     double m_releaseStartFactor = 0.0; /**< Level at whenever release event occurs */
     double m_curTime = 0.0; /**< Current time of envelope stage in seconds */
 public:
diff --git a/lib/SongState.cpp b/lib/SongState.cpp
index 0f4f823..69dd309 100644
--- a/lib/SongState.cpp
+++ b/lib/SongState.cpp
@@ -179,9 +179,9 @@ bool SongState::Channel::advance(Sequencer& seq, int32_t ticks)
             /* See if there's an upcoming pitch change in this interval */
             const unsigned char* ptr = m_pitchWheelData;
             uint32_t deltaTicks = DecodeRLE(ptr);
-            if (deltaTicks != -1)
+            if (deltaTicks != 0xffffffff)
             {
-                uint32_t nextTick = m_lastPitchTick + deltaTicks;
+                int32_t nextTick = m_lastPitchTick + deltaTicks;
                 if (pitchTick + remPitchTicks > nextTick)
                 {
                     /* Update pitch */
@@ -212,9 +212,9 @@ bool SongState::Channel::advance(Sequencer& seq, int32_t ticks)
             /* See if there's an upcoming modulation change in this interval */
             const unsigned char* ptr = m_modWheelData;
             uint32_t deltaTicks = DecodeRLE(ptr);
-            if (deltaTicks != -1)
+            if (deltaTicks != 0xffffffff)
             {
-                uint32_t nextTick = m_lastModTick + deltaTicks;
+                int32_t nextTick = m_lastModTick + deltaTicks;
                 if (modTick + remModTicks > nextTick)
                 {
                     /* Update modulation */
diff --git a/lib/Voice.cpp b/lib/Voice.cpp
index 9a265f8..7bc87e9 100644
--- a/lib/Voice.cpp
+++ b/lib/Voice.cpp
@@ -201,7 +201,8 @@ std::list<std::shared_ptr<Voice>>::iterator Voice::_destroyVoice(Voice* voice)
 static void ApplyVolume(float vol, int16_t& samp)
 {
     /* -10dB to 0dB mapped to full volume range */
-    float factor = (std::pow(10.f, vol - 1.f) - 0.1f) * (1.f / 0.9f);
+    float factor = std::sqrt(std::pow(10.f, (vol - 1.f))) - 0.317f;
+    if (factor < 0.f) factor = 0.f;
     samp *= factor;
 }