Ticket #3542: scumm-timers.patch

engines/scumm/scumm.cpp

@@ -1700 +1700 @@
 #pragma mark --- Main loop ---
 #pragma mark -
 
-enum {
-        kTickDuration = 15      // Corresponds to a tick frequency of 1000/15 = 66.6 Hz
-};
-
 int ScummEngine::go() {
         _engineStartTime = _system->getMillis() / 1000;
 
@@ -1715 +1711 @@
                 _saveLoadFlag = 0;
         }
 
-        int delta = 0;
-        int diff = _system->getMillis();
+        int diff = 0;   // Duration of one loop iteration
 
         while (!_quit) {
 
@@ -1727 +1722 @@
                 // that it will be in a different state each time you run the program.
                 _rnd.getRandomNumber(2);
 
-                diff -= _system->getMillis();
-                waitForTimer(delta * kTickDuration + diff);
-                diff = _system->getMillis();
-                delta = scummLoop(delta);
+                // Notify the script about how much time has passed, in ticks (60 ticks per second)
+                if (VAR_TIMER != 0xFF)
+                        VAR(VAR_TIMER) = diff * 60 / 1000;
+                if (VAR_TIMER_TOTAL != 0xFF)
+                        VAR(VAR_TIMER_TOTAL) += diff * 60 / 1000;
 
+                // Determine how long to wait before the next loop iteration should start
+                int delta = (VAR_TIMER_NEXT != 0xFF) ? VAR(VAR_TIMER_NEXT) : 4;
                 if (delta < 1)  // Ensure we don't get into an endless loop
                         delta = 1;  // by not decreasing sleepers.
 
+                // Wait...
+                waitForTimer(delta * 1000 / 60 - diff);
+
+                // Start the stop watch!
+                diff = _system->getMillis();
+
+                // Run the main loop
+                scummLoop(delta);
+
+                // Halt the stop watch and compute how much time this iteration took.
+                diff = _system->getMillis() - diff;
+
+
                 if (_quit) {
                         // TODO: Maybe perform an autosave on exit?
                 }
@@ -1763 +1774 @@
         }
 }
 
-int ScummEngine::scummLoop(int delta) {
+void ScummEngine::scummLoop(int delta) {
         if (_game.version >= 3) {
                 VAR(VAR_TMR_1) += delta;
                 VAR(VAR_TMR_2) += delta;
@@ -1777 +1788 @@
                         VAR(41) += delta;
                 }
         }
-        if (VAR_TIMER_TOTAL != 0xFF)
-                VAR(VAR_TIMER_TOTAL) += delta;
 
         if (delta > 15)
                 delta = 15;
@@ -1816 +1825 @@
                         // to get it correct for all games. Without the ability to watch/listen to the
                         // original games, I can't do that myself.
                         const int MUSIC_DELAY = 350;
-                        _tempMusic += delta * kTickDuration;    // Convert delta to milliseconds
+                        _tempMusic += delta * 1000 / 60;        // Convert delta to milliseconds
                         if (_tempMusic >= MUSIC_DELAY) {
                                 _tempMusic -= MUSIC_DELAY;
                                 VAR(VAR_MUSIC_TIMER) += 1;
@@ -1879 +1888 @@
         checkAndRunSentenceScript();
 
         if (_quit)
-                return 0;
+                return;
 
         // HACK: If a load was requested, immediately perform it. This avoids
         // drawing the current room right after the load is request but before
@@ -1935 +1944 @@
 
         /* show or hide mouse */
         CursorMan.showMouse(_cursor.state > 0);
-
-        if (VAR_TIMER != 0xFF)
-                VAR(VAR_TIMER) = 0;
-        return (VAR_TIMER_NEXT != 0xFF) ? VAR(VAR_TIMER_NEXT) : 4;
-
 }
 
 #ifndef DISABLE_HE
-int ScummEngine_v90he::scummLoop(int delta) {
+void ScummEngine_v90he::scummLoop(int delta) {
         _moviePlay->handleNextFrame();
         if (_game.heversion >= 98) {
                 _logicHE->startOfFrame();
         }
 
-        int ret = ScummEngine::scummLoop(delta);
+        ScummEngine::scummLoop(delta);
 
         _sprite->updateImages();
         if (_game.heversion >= 98) {
                 _logicHE->endOfFrame();
         }
-
-        return ret;
 }
 #endif
 

engines/scumm/scumm.h

@@ -467 +467 @@
         int getTalkspeed();
 
         // Scumm main loop & helper functions.
-        virtual int scummLoop(int delta);
+        virtual void scummLoop(int delta);
         virtual void scummLoop_updateScummVars();
         virtual void scummLoop_handleSaveLoad();
         virtual void scummLoop_handleDrawing();

engines/scumm/he/intern_he.h

@@ -485 +485 @@
         virtual void setupScummVars();
         virtual void resetScummVars();
 
-        virtual int scummLoop(int delta);
+        virtual void scummLoop(int delta);
         virtual void scummLoop_handleDrawing();
         virtual void runBootscript();