Attempt to closely aproximate HMI volume model

1 files changed, 19 insertions, 2 deletions

diff --git a/src/adlmidi_opl3.cpp b/src/adlmidi_opl3.cpp
index 334db43..96fa707 100644
--- a/src/adlmidi_opl3.cpp
+++ b/src/adlmidi_opl3.cpp
@@ -239,6 +239,22 @@ static const uint_fast32_t s_ail_vel_graph[16] =
     106, 109, 112, 115, 118, 121, 124, 127
 };
 
+//! a VERY APROXIMAL HMI volume model, TODO: Research accurate one!
+static const uint_fast32_t s_hmi_volume_table[128] =
+{
+    0x3f, 0x3f, 0x3a, 0x35, 0x35, 0x30, 0x30, 0x2c, 0x2c, 0x29, 0x29,
+    0x25, 0x25, 0x24, 0x24, 0x23, 0x23, 0x22, 0x21, 0x21, 0x20, 0x20,
+    0x1f, 0x1f, 0x1e, 0x1e, 0x1d, 0x1d, 0x1c, 0x1c, 0x1b, 0x1b, 0x1a,
+    0x1a, 0x1a, 0x19, 0x19, 0x19, 0x18, 0x18, 0x18, 0x17, 0x17, 0x17,
+    0x16, 0x16, 0x16, 0x15, 0x15, 0x15, 0x14, 0x14, 0x14, 0x14, 0x13,
+    0x13, 0x13, 0x13, 0x12, 0x12, 0x12, 0x12, 0x11, 0x11, 0x11, 0x10,
+    0x10, 0x10, 0x0f, 0x0f, 0x0f, 0x0e, 0x0e, 0x0e, 0x0d, 0x0d, 0x0d,
+    0x0c, 0x0c, 0x0c, 0x0b, 0x0b, 0x0b, 0x0b, 0x0a, 0x0a, 0x0a, 0x0a,
+    0x09, 0x09, 0x09, 0x09, 0x08, 0x08, 0x08, 0x08, 0x07, 0x07, 0x07,
+    0x07, 0x06, 0x06, 0x06, 0x06, 0x05, 0x05, 0x05, 0x05, 0x04, 0x04,
+    0x04, 0x04, 0x03, 0x03, 0x03, 0x03, 0x03, 0x02, 0x02, 0x02, 0x02,
+    0x02, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00
+};
 
 enum
 {
@@ -634,13 +650,14 @@ void OPL3::touchNote(size_t c,
         if(m_masterVolume < 127)
             midiVolume = (midiVolume * m_masterVolume) / 127;
     }
+    break;
 
     case Synth::VOLUME_HMI:
     {
         /* Temporarily copying DMX volume model. TODO: Reverse-engine the actual HMI volume model! */
         volume = (channelVolume * channelExpression * m_masterVolume) / 16129;
-        volume = (s_dmx_volume_model[volume] + 1) << 1;
-        volume = (s_dmx_volume_model[(velocity < 128) ? velocity : 127] * volume) >> 9;
+        volume = (((velocity < 128) ? velocity : 127) * volume) / 127;
+        volume = 63 - s_hmi_volume_table[volume];
     }
     break;
     }