Ticket #8058: cd-timer.diff

scummvm/scumm/saveload.cpp

@@ -159 +159 @@
 
         initBGBuffers(_scrHeight);
 
+        _sound->resumeCDTimer();
+
         CHECK_HEAP debug(1, "State loaded from '%s'", filename);
 
 

scummvm/scumm/scummvm.cpp

@@ -331 +331 @@
 
 int Scumm::scummLoop(int delta)
 {
-        static int counter = 0;
-
 #ifndef _WIN32_WCE
         if (_debugger)
                 _debugger->on_frame();
@@ -371 +369 @@
         _vars[VAR_MOUSE_Y] = mouse.y;
         _vars[VAR_DEBUGMODE] = _debugMode;
 
-        if (_features & GF_AUDIOTRACKS) {               
-                if (delta) {
-                        if (delta == 1) {
-                                // Better sync with the Loom CD intro
-                                _vars[VAR_MI1_TIMER]++;
-                        } else if (++counter != 2)
-                                _vars[VAR_MI1_TIMER] += 5;
-                        else {
-                                counter = 0;
-                                _vars[VAR_MI1_TIMER] += 6;
-                        }                               
-                }
+        if (_features & GF_AUDIOTRACKS) {
+                _vars[VAR_MI1_TIMER] = _sound->readCDTimer();
         } else if (_features & GF_OLD256) {
 
                 if(tempMusic == 3) {

scummvm/scumm/sound.cpp

@@ -1028 +1028 @@
         return -1;
 }
 
+// We use a real timer in an attempt to get better sync with CD tracks. This is
+// necessary for games like Loom CD.
+
+static void cd_timer_handler(void *ptr)
+{
+        Scumm *scumm = (Scumm *) ptr;
+        scumm->_sound->_cd_timer_value += 5;
+}
+
+int Sound::readCDTimer()
+{
+        return _cd_timer_value;
+}
+
+void Sound::startCDTimer()
+{
+        int timer_interval;
+
+        // The timer interval has been tuned for Loom CD and the Monkey 1
+        // intro. I have to use 83 for Loom, or there will be a nasty stutter
+        // when Chaos first appears, and I have to use 84 for Monkey 1 or the
+        // intro music will be cut short.
+
+        if (_scumm->_gameId == GID_LOOM256)
+                timer_interval = 83;
+        else 
+                timer_interval = 84;
+
+        _scumm->_timer->installProcedure(&cd_timer_handler, timer_interval);
+}
+
+void Sound::stopCDTimer()
+{
+        _cd_timer_value = 0;
+        _scumm->_timer->releaseProcedure(&cd_timer_handler);
+        if (_scumm->_features & GF_AUDIOTRACKS) {
+                _scumm->_vars[_scumm->VAR_MI1_TIMER] = 0;
+        }
+}
+
+void Sound::restartCDTimer()
+{
+        stopCDTimer();
+        startCDTimer();
+}
+
+void Sound::resumeCDTimer()
+{
+        // This function will be called after a savegame has been reloaded,
+        // in case we have to get the timer running again.
+
+        if ((_scumm->_features & GF_AUDIOTRACKS) && _scumm->_vars[_scumm->VAR_MI1_TIMER] > 0) {
+                _cd_timer_value = _scumm->_vars[_scumm->VAR_MI1_TIMER];
+                startCDTimer();
+        }
+}
+
 void Sound::playCDTrack(int track, int num_loops, int start, int delay)
 {
 #ifdef COMPRESSED_SOUND_FILE
         if (playMP3CDTrack(track, num_loops, start, delay) == -1)
 #endif
                 _scumm->_system->play_cdrom(track, num_loops, start, delay);
+
+        // Start the timer after starting the track. Starting an MP3 track is
+        // almost instantaneous, but a CD player may take some time. Hopefully
+        // play_cdrom() will block during that delay.
+
+        restartCDTimer();
 }
 
 void Sound::stopCD()
 {
+        stopCDTimer();
 #ifdef COMPRESSED_SOUND_FILE
         if (stopMP3CD() == -1)
 #endif

scummvm/scumm/sound.h

@@ -23 +23 @@
 
 #include "scummsys.h"
 #include "sound/mixer.h"
+#include "common/timer.h"
 
 class Scumm;
 class File;
@@ -88 +89 @@
 
 #endif
 
+        int _cd_timer_value;
         bool _soundsPaused;
         int16 _sound_volume_master, _sound_volume_music, _sound_volume_sfx;
         byte _sfxMode;
@@ -124 +126 @@
         int playSfxSound(void *sound, uint32 size, uint rate, bool isUnsigned);
         int playSfxSound_MP3(void *sound, uint32 size);
 
+        int readCDTimer();
+        void startCDTimer();
+        void stopCDTimer();
+        void restartCDTimer();
+        void resumeCDTimer();
+
         void playCDTrack(int track, int num_loops, int start, int delay);
         void stopCD();
         int pollCD();