SHERLOCK: Make random pixel transitions more like the original

3 files changed, 39 insertions, 15 deletions

diff --git a/engines/sherlock/events.cpp b/engines/sherlock/events.cpp
index c6c013193c..b2d9fc65e8 100644
--- a/engines/sherlock/events.cpp
+++ b/engines/sherlock/events.cpp
@@ -166,18 +166,32 @@ void EventsManager::wait(int numFrames) {
 }
 
 bool EventsManager::delay(uint32 time, bool interruptable) {
-	uint32 delayEnd = g_system->getMillis() + time;
-
-	while (!_vm->shouldQuit() && g_system->getMillis() < delayEnd) {
-		pollEventsAndWait();
-
-		if (interruptable && (isKeyPressed() || _mouseClicked)) {
-			clearEvents();
-			return false;
+	// Different handling for really short versus extended times
+	if (time < 10) {
+		// For really short periods, simply delay by the desired amount
+		pollEvents();
+		g_system->delayMillis(time);
+		bool result = !(interruptable && (isKeyPressed() || _mouseClicked));
+
+		clearEvents();
+		return result;
+	} else {
+		// For long periods go into a loop where we delay by 10ms at a time and then
+		// check for events. This ensures for longer delays that responsiveness is
+		// maintained
+		uint32 delayEnd = g_system->getMillis() + time;
+
+		while (!_vm->shouldQuit() && g_system->getMillis() < delayEnd) {
+			pollEventsAndWait();
+
+			if (interruptable && (isKeyPressed() || _mouseClicked)) {
+				clearEvents();
+				return false;
+			}
 		}
-	}
 
-	return true;
+		return true;
+	}
 }
 
 /**
diff --git a/engines/sherlock/screen.cpp b/engines/sherlock/screen.cpp
index 41cf19e48c..7a4d4863ac 100644
--- a/engines/sherlock/screen.cpp
+++ b/engines/sherlock/screen.cpp
@@ -30,6 +30,7 @@ namespace Sherlock {
 Screen::Screen(SherlockEngine *vm) : Surface(SHERLOCK_SCREEN_WIDTH, SHERLOCK_SCREEN_HEIGHT), _vm(vm),
 		_backBuffer(SHERLOCK_SCREEN_WIDTH, SHERLOCK_SCREEN_HEIGHT),
 		_backBuffer2(SHERLOCK_SCREEN_WIDTH, SHERLOCK_SCREEN_HEIGHT) {
+	_transitionSeed = 1;
 	setFont(1);
 }
 
@@ -178,15 +179,23 @@ bool Screen::unionRectangle(Common::Rect &destRect, const Common::Rect &src1, co
  */
 void Screen::randomTransition() {
 	EventsManager &events = *_vm->_events;
+	const int TRANSITION_MULTIPLIER = 0x15a4e35;
+	_dirtyRects.clear();
 
 	for (int idx = 0; idx <= 65535; ++idx) {
-		int offset = _vm->getRandomNumber(this->w * this->h);
-		*((byte *)getPixels() + offset) = *((const byte *)_backBuffer.getPixels() + offset);
+		_transitionSeed = _transitionSeed * TRANSITION_MULTIPLIER + 1;
+		int offset = _transitionSeed & 65535;
+
+		if (offset < (SHERLOCK_SCREEN_WIDTH * SHERLOCK_SCREEN_HEIGHT))
+			*((byte *)getPixels() + offset) = *((const byte *)_backBuffer.getPixels() + offset);
 	
 		if (idx != 0 && (idx % 100) == 0) {
-			_dirtyRects.clear();
-			addDirtyRect(Common::Rect(0, 0, this->w, this->h));
-			events.delay(5);
+			// Ensure there's a full screen dirty rect for the next frame update
+			if (_dirtyRects.empty())
+				addDirtyRect(Common::Rect(0, 0, this->w, this->h));
+			
+			events.pollEvents();
+			events.delay(1);
 		}
 	}
 
diff --git a/engines/sherlock/screen.h b/engines/sherlock/screen.h
index 0c0175d2ed..78ccffc575 100644
--- a/engines/sherlock/screen.h
+++ b/engines/sherlock/screen.h
@@ -42,6 +42,7 @@ private:
 	SherlockEngine *_vm;
 	int _fontNumber;
 	Common::List<Common::Rect> _dirtyRects;
+	uint32 _transitionSeed;
 
 	void mergeDirtyRects();