commit 816f94a8220b1fe3315a64faca855dcf90c44c6b
Author:     khokh2001 <alexeytf2@gmail.com>
AuthorDate: Mon Oct 5 22:06:50 2015 +0900
Commit:     khokh2001 <alexeytf2@gmail.com>
CommitDate: Mon Oct 5 22:06:50 2015 +0900

    opl: DMX MIDI channel volume calculation fix.
---
 src/i_oplmusic.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 47 insertions(+), 9 deletions(-)

diff --git a/src/i_oplmusic.c b/src/i_oplmusic.c
index 354c6a42..990f8f3f 100644
--- a/src/i_oplmusic.c
+++ b/src/i_oplmusic.c
@@ -85,6 +85,7 @@ typedef struct
     // Volume level

     int volume;
+    int volume_base;

     // Pan

@@ -311,6 +312,7 @@ static opl_driver_ver_t opl_drv_ver = opl_doom_1_9;
 static boolean music_initialized = false;

 //static boolean musicpaused = false;
+static int start_music_volume;
 static int current_music_volume;

 // GENMIDI lump instrument data:
@@ -572,8 +574,7 @@ static void SetVoiceVolume(opl_voice_t *voice, unsigned int volume)

     // Multiply note volume and channel volume to get the actual volume.

-    midi_volume = 2 * (volume_mapping_table[(voice->channel->volume
-                  * current_music_volume) / 127] + 1);
+    midi_volume = 2 * (volume_mapping_table[voice->channel->volume] + 1);

     full_volume = (volume_mapping_table[voice->note_volume] * midi_volume)
                 >> 9;
@@ -645,11 +646,19 @@ static void InitVoices(void)
     }
 }

+static void SetChannelVolume(opl_channel_data_t *channel, unsigned int volume,
+                             boolean clip_start);
+
 // Set music volume (0 - 127)

 static void I_OPL_SetMusicVolume(int volume)
 {
-    unsigned int i;
+    unsigned int i, j;
+
+    if (current_music_volume == volume)
+    {
+        return;
+    }

     // Internal state variable.

@@ -657,11 +666,20 @@ static void I_OPL_SetMusicVolume(int volume)

     // Update the volume of all voices.

-    for (i = 0; i < num_opl_voices; ++i)
+    for (i = 0; i < num_tracks; ++i)
     {
-        if (voices[i].channel != NULL)
+        for (j = 0; j < MIDI_CHANNELS_PER_TRACK; ++j)
         {
-            SetVoiceVolume(&voices[i], voices[i].note_volume);
+            if (j == 9)
+            {
+                SetChannelVolume(&tracks[i].channels[j],
+                                 volume, false);
+            }
+            else
+            {
+                SetChannelVolume(&tracks[i].channels[j],
+                                 tracks[i].channels[j].volume_base, false);
+            }
         }
     }
 }
@@ -1117,10 +1135,23 @@ static void ProgramChangeEvent(opl_track_data_t *track, midi_event_t *event)
     // channel, and change the instrument.
 }

-static void SetChannelVolume(opl_channel_data_t *channel, unsigned int volume)
+static void SetChannelVolume(opl_channel_data_t *channel, unsigned int volume,
+                             boolean clip_start)
 {
     unsigned int i;

+    channel->volume_base = volume;
+
+    if (volume > current_music_volume)
+    {
+        volume = current_music_volume;
+    }
+
+    if (clip_start && volume > start_music_volume)
+    {
+        volume = start_music_volume;
+    }
+
     channel->volume = volume;

     // Update all voices that this channel is using.
@@ -1232,7 +1263,7 @@ static void ControllerEvent(opl_track_data_t *track, midi_event_t *event)
     switch (controller)
     {
         case MIDI_CONTROLLER_MAIN_VOLUME:
-            SetChannelVolume(channel, param);
+            SetChannelVolume(channel, param, true);
             break;

         case MIDI_CONTROLLER_PAN:
@@ -1379,6 +1410,10 @@ static void RestartSong(void *unused)

     running_tracks = num_tracks;

+    start_music_volume = current_music_volume;
+
+    I_SetMusicVolume(current_music_volume);
+
     for (i = 0; i < num_tracks; ++i)
     {
         MIDI_RestartIterator(tracks[i].iter);
@@ -1453,7 +1488,8 @@ static void InitChannel(opl_track_data_t *track, opl_channel_data_t *channel)
     // TODO: Work out sensible defaults?

     channel->instrument = &main_instrs[0];
-    channel->volume = 127;
+    channel->volume = current_music_volume;
+    channel->volume_base = 127;
     channel->pan = 0x30;
     channel->bend = 0;
 }
@@ -1507,6 +1543,8 @@ static void I_OPL_PlaySong(void *handle, boolean looping)

     us_per_beat = 500 * 1000;

+    start_music_volume = current_music_volume;
+
     for (i = 0; i < num_tracks; ++i)
     {
         StartTrack(file, i);