opl: Change library to use us instead of ms.

Multi-track MIDI files are played back using separate callback chains
for each track, and this introduces the possibility of one track
becoming out of sync with the others. This was noticeable in WADs
that use multi-track MIDIs, such as Alien Vendetta. Increase the
timing resolution to microsecond precision to fix this.

1 files changed, 2 insertions, 2 deletions

diff --git a/opl/examples/droplay.c b/opl/examples/droplay.c
index 99456050..7b20e03d 100644
--- a/opl/examples/droplay.c
+++ b/opl/examples/droplay.c
@@ -139,7 +139,7 @@ void TimerCallback(void *data)
 
     // Schedule the next timer callback.
 
-    OPL_SetCallback(delay, TimerCallback, timer_data);
+    OPL_SetCallback(delay * OPL_MS, TimerCallback, timer_data);
 }
 
 void PlayFile(char *filename)
@@ -183,7 +183,7 @@ void PlayFile(char *filename)
         running = timer_data.running;
         OPL_Unlock();
 
-        SDL_Delay(100);
+        SDL_Delay(100 * OPL_MS);
     } while (running);
 
     fclose(timer_data.fstream);