Make DMX volume model be more accurate

(thanks to NukeYKT for a hint)

2 files changed, 8 insertions, 2 deletions

diff --git a/README.md b/README.md
index db07572..2f00e5f 100644
--- a/README.md
+++ b/README.md
@@ -183,6 +183,7 @@ To build that example you will need to have installed SDL2 library.
  * Reworked rhythm-mode percussions system, WOPL banks with rhythm-mode percussions
  * Added Public Domain Opal OPL3 emulator made by Reality (a team who originally made the Reality Adlib Tracker) (Thanks to [Jean Pierre Cimalando](https://github.com/jpcima) for a work!)
  * Added LGPL licensed JavaOPL3 emulator made by Robson Cozendey in Java and later rewritten into C++ for GZDoom (Thanks to [Jean Pierre Cimalando](https://github.com/jpcima) for a work!)
+ * Fixed an accuracy of the DMX volume model
 
 ## 1.4.0   2018-10-01
  * Implemented a full support for Portamento! (Thanks to [Jean Pierre Cimalando](https://github.com/jpcima) for a work!)
diff --git a/src/adlmidi_midiplay.cpp b/src/adlmidi_midiplay.cpp
index 5b81d83..61bdf95 100644
--- a/src/adlmidi_midiplay.cpp
+++ b/src/adlmidi_midiplay.cpp
@@ -704,8 +704,13 @@ void MIDIplay::realTime_ChannelAfterTouch(uint8_t channel, uint8_t atVal)
 void MIDIplay::realTime_Controller(uint8_t channel, uint8_t type, uint8_t value)
 {
     Synth &synth = *m_synth;
+
+    if(value > 127) // Allowed values 0~127 only
+        value = 127;
+
     if(static_cast<size_t>(channel) > m_midiChannels.size())
         channel = channel % 16;
+
     switch(type)
     {
     case 1: // Adjust vibrato
@@ -1311,8 +1316,8 @@ void MIDIplay::noteUpdate(size_t midCh,
 
             case Synth::VOLUME_DMX:
             {
-                volume = 2 * (m_midiChannels[midCh].volume * m_midiChannels[midCh].expression * m_masterVolume / 16129) + 1;
-                //volume = 2 * (Ch[MidCh].volume) + 1;
+                volume = (m_midiChannels[midCh].volume * m_midiChannels[midCh].expression * m_masterVolume) / 16129;
+                volume = (DMX_volume_mapping_table[volume] + 1) << 1;
                 volume = (DMX_volume_mapping_table[(vol < 128) ? vol : 127] * volume) >> 9;
             }
             break;