shithub: choc

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ref: b2e5952c454dd46b29ca6c64e742b4505c20d5b7
parent: f102dc1c7d5e83c59b87afaf16c16a64c89db0c5
author: Simon Howard <fraggle@gmail.com>
date: Tue May 6 18:03:00 EDT 2014

oplmusic: Handle key-on with volume 0 as key-off.

Some MIDI files, such as the music tracks in AV.wad, use a second
"key on" event with a volume of zero to mean "key off". Handle this
case correctly.

--- a/src/i_oplmusic.c
+++ b/src/i_oplmusic.c
@@ -881,11 +881,20 @@
            event->data.channel.param2);
 */
 
-    // The channel.
-
-    channel = &track->channels[event->data.channel.channel];
     key = event->data.channel.param1;
     volume = event->data.channel.param2;
+
+    // A volume of zero means key off. Some MIDI tracks, eg. the ones
+    // in AV.wad, use a second key on with a volume of zero to mean
+    // key off.
+    if (volume <= 0)
+    {
+        KeyOffEvent(track, event);
+        return;
+    }
+
+    // The channel.
+    channel = &track->channels[event->data.channel.channel];
 
     // Percussion channel (10) is treated differently.