[Scummvm-git-logs] scummvm master -> 996938b891a07834887e386e0a972aea3f4f47ad

[AndywinXp]

This automated email contains information about 1 new commit which have been
pushed to the 'scummvm' repo located at https://github.com/scummvm/scummvm .

Summary:
996938b891 SCUMM: ZAK (FM-Towns): Insert workaround for intro timing


Commit: 996938b891a07834887e386e0a972aea3f4f47ad
    https://github.com/scummvm/scummvm/commit/996938b891a07834887e386e0a972aea3f4f47ad
Author: AndywinXp (andywinxp at gmail.com)
Date: 2024-08-19T15:45:40+02:00

Commit Message:
SCUMM: ZAK (FM-Towns): Insert workaround for intro timing

This fixes and closes #9591:
"SCUMM: ZAK (FM-Towns): Intro animation runs faster than intro music"

Also, make sure that the timer frequency is always used by calling
getTimerFrequency()...

Changed paths:
    engines/scumm/input.cpp
    engines/scumm/scumm.cpp


diff --git a/engines/scumm/input.cpp b/engines/scumm/input.cpp
index 6aeb9dc3a0f..4da6a1803bf 100644
--- a/engines/scumm/input.cpp
+++ b/engines/scumm/input.cpp
@@ -604,7 +604,7 @@ void ScummEngine::waitForBannerInput(int32 waitTime, Common::KeyState &ks, bool
 
 	if (waitTime && waitTime != -1) {
 		uint32 millis = _system->getMillis();
-		while (((_system->getMillis() - millis) * (_timerFrequency / 4) / 1000) < waitTime) {
+		while (((_system->getMillis() - millis) * (getTimerFrequency() / 4) / 1000) < waitTime) {
 			waitForTimer(1); // Allow the engine to update the screen and fetch new inputs...
 
 			if (_game.version < 7 && (_guiCursorAnimCounter++ & 16)) {
diff --git a/engines/scumm/scumm.cpp b/engines/scumm/scumm.cpp
index 44320acd202..03859d598f0 100644
--- a/engines/scumm/scumm.cpp
+++ b/engines/scumm/scumm.cpp
@@ -2506,7 +2506,7 @@ Common::Error ScummEngine::go() {
 
 void ScummEngine::waitForTimer(int quarterFrames, bool freezeMacGui) {
 	uint32 endTime, cur;
-	uint32 msecDelay = getIntegralTime(quarterFrames * (1000 / _timerFrequency));
+	uint32 msecDelay = getIntegralTime(quarterFrames * (1000 / getTimerFrequency()));
 
 	if (_fastMode & 2)
 		msecDelay = 0;
@@ -2613,6 +2613,32 @@ void ScummEngine::setTimerAndShakeFrequency() {
 }
 
 double ScummEngine::getTimerFrequency() {
+	// HACK for bug #9591:
+	// "SCUMM: ZAK (FM-Towns): Intro animation runs faster than intro music".
+	//
+	// There is no way around it: the original game relied on the (low) speed of the hardware
+	// for keeping the intro song in sync with the visuals. And by "sync" I mean just having
+	// the song end when the visuals are done. Just two checks are being done on VAR_MUSIC_TIMER
+	// within the relevant scripts at the beginning of the intro, and then in the end there is
+	// this check which fails because at that point Var[151 Bit 8] seems to be deactivated:
+	// 
+	// if (Var[151 Bit 8]) {
+	//   breakHere();
+	//   VAR_RESULT = isSoundRunning(93);
+	//   unless (!VAR_RESULT) goto 0441;
+	// } else {
+	//   delay(240);
+	// }
+	//
+	// Even if the check above worked, we would end up with the visual finishing about 14 seconds
+	// earlier than the audio, and stalling until the audio is done, which is not pretty.
+	//
+	// The best fit for the simulated slowdown seems to a quarter-frame rate of 200.0 Hz (50 Hz),
+	// while the CD audio timer continues to operate at 60.0 Hz, as it should.
+
+	if (_game.id == GID_ZAK && _game.platform == Common::kPlatformFMTowns && _sound->getCurrentCDSound() == 93)
+		return 200.0;
+
 	return _timerFrequency;
 }
 
@@ -2620,7 +2646,7 @@ double ScummEngine::getAmigaMusicTimerFrequency() {
 	// Similarly to MI1, LOOM in PAL mode operates at 50Hz but the audio engine
 	// compensates the speed factor to play music at the correct speed.
 	// We simply feed the NTSC speed to the Paula audio engine to account for that.
-	return _game.id == GID_LOOM ? AMIGA_NTSC_VBLANK_RATE : _timerFrequency;
+	return _game.id == GID_LOOM ? AMIGA_NTSC_VBLANK_RATE : getTimerFrequency();
 }
 
 void ScummEngine_v0::scummLoop(int delta) {
@@ -2711,7 +2737,7 @@ void ScummEngine::scummLoop(int delta) {
 			VAR(VAR_MUSIC_TIMER) = _sound->getMusicTimer();
 		} else if (_musicEngine) {
 			// The music engine generates the timer data for us.
-			VAR(VAR_MUSIC_TIMER) = _musicEngine->getMusicTimer() * _timerFrequency / 240.0;
+			VAR(VAR_MUSIC_TIMER) = _musicEngine->getMusicTimer() * getTimerFrequency() / 240.0;
 		}
 	}