TOLTECS: Improve the shake screen effects during movies

I don't know how often the original shook the screen (perhaps as
often as it could?), but at least we now have the opportunity to
shake the screen more than once per movie frame.

3 files changed, 17 insertions, 8 deletions

diff --git a/engines/toltecs/movie.cpp b/engines/toltecs/movie.cpp
index 44b52b113a..35accb5d93 100644
--- a/engines/toltecs/movie.cpp
+++ b/engines/toltecs/movie.cpp
@@ -125,11 +125,7 @@ void MoviePlayer::playMovie(uint resIndex) {
 		case kChunkFirstImage:
 		case kChunkSubsequentImages:
 			unpackRle(chunkBuffer, _vm->_screen->_backScreen);
-			// TODO: Rework this
-			_vm->_screen->updateShakeScreen();
 			_vm->_screen->_fullRefresh = true;
-			_vm->updateInput();
-			_vm->drawScreen();
 
 			_soundChunkFramesLeft--;
 			if (_soundChunkFramesLeft <= _framesPerSoundChunk) {
@@ -137,7 +133,12 @@ void MoviePlayer::playMovie(uint resIndex) {
 			}
 
 			while (_vm->_mixer->getSoundElapsedTime(_audioStreamHandle) < (1000 * frame) / 9) {
-				g_system->delayMillis(10);
+				if (_vm->_screen->_shakeActive && _vm->_screen->updateShakeScreen()) {
+					_vm->_screen->_fullRefresh = true;
+				}
+				_vm->updateInput();
+				_vm->drawScreen();
+				// Note: drawScreen() calls delayMillis()
 			}
 
 			frame++;
diff --git a/engines/toltecs/screen.cpp b/engines/toltecs/screen.cpp
index 32202ad13e..c8d6740b02 100644
--- a/engines/toltecs/screen.cpp
+++ b/engines/toltecs/screen.cpp
@@ -43,9 +43,11 @@ Screen::Screen(ToltecsEngine *vm) : _vm(vm) {
 
 	// Screen shaking
 	_shakeActive = false;
+	_shakeTime = 0;
 	_shakeCounterInit = 0;
 	_shakeCounter = 0;
 	_shakePos = 0;
+	_shakeTime = 0;
 
 	// Verb line
 	_verbLineNum = 0;
@@ -156,6 +158,7 @@ void Screen::drawGuiImage(int16 x, int16 y, uint resIndex) {
 
 void Screen::startShakeScreen(int16 shakeCounter) {
 	_shakeActive = true;
+	_shakeTime = 0;
 	_shakeCounterInit = shakeCounter;
 	_shakeCounter = shakeCounter;
 	_shakePos = 0;
@@ -166,15 +169,19 @@ void Screen::stopShakeScreen() {
 	_vm->_system->setShakePos(0);
 }
 
-void Screen::updateShakeScreen() {
-	if (_shakeActive) {
+bool Screen::updateShakeScreen() {
+	// Assume shaking happens no more often than 50 times per second
+	if (_shakeActive && _vm->_system->getMillis() - _shakeTime >= 20) {
+		_shakeTime = _vm->_system->getMillis();
 		_shakeCounter--;
 		if (_shakeCounter == 0) {
 			_shakeCounter = _shakeCounterInit;
 			_shakePos ^= 8;
 			_vm->_system->setShakePos(_shakePos);
+			return true;
 		}
 	}
+	return false;
 }
 
 void Screen::addStaticSprite(byte *spriteItem) {
diff --git a/engines/toltecs/screen.h b/engines/toltecs/screen.h
index 315e9a45c3..788cde50c6 100644
--- a/engines/toltecs/screen.h
+++ b/engines/toltecs/screen.h
@@ -161,7 +161,7 @@ public:
 
 	void startShakeScreen(int16 shakeCounter);
 	void stopShakeScreen();
-	void updateShakeScreen();
+	bool updateShakeScreen();
 
 	// Sprite list
 	void addStaticSprite(byte *spriteItem);
@@ -221,6 +221,7 @@ public:
 
 	// Screen shaking
 	bool _shakeActive;
+	uint32 _shakeTime;
 	int16 _shakeCounterInit, _shakeCounter;
 	int _shakePos;