From cfdbfaa28eb29cb17185d3d3d1ddde8c89a369c1 Mon Sep 17 00:00:00 2001
From: Filippos Karapetis
Date: Mon, 14 Jun 2010 08:36:52 +0000
Subject: SCI: Limit the screen refresh rate to 60fps

svn-id: r49647
---
 engines/sci/engine/savegame.cpp |  1 +
 engines/sci/engine/state.h      |  1 +
 engines/sci/event.cpp           | 10 ++++++++--
 engines/sci/sci.cpp             |  2 +-
 4 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/engines/sci/engine/savegame.cpp b/engines/sci/engine/savegame.cpp
index 8c743189d7..a7310d2b6a 100644
--- a/engines/sci/engine/savegame.cpp
+++ b/engines/sci/engine/savegame.cpp
@@ -877,6 +877,7 @@ void gamestate_restore(EngineState *s, Common::SeekableReadStream *fh) {
 	// Time state:
 	s->lastWaitTime = g_system->getMillis();
 	s->gameStartTime = g_system->getMillis();
+	s->_screenUpdateTime = g_system->getMillis();
 
 #ifdef USE_OLD_MUSIC_FUNCTIONS
 	s->_sound._it = NULL;
diff --git a/engines/sci/engine/state.h b/engines/sci/engine/state.h
index 1b1a1fa86c..b47b739007 100644
--- a/engines/sci/engine/state.h
+++ b/engines/sci/engine/state.h
@@ -113,6 +113,7 @@ public:
 
 	uint32 gameStartTime; /**< The time at which the interpreter was started */
 	uint32 lastWaitTime; /**< The last time the game invoked Wait() */
+	uint32 _screenUpdateTime;	/**< The last time the game updated the screen */
 
 	void wait(int16 ticks);
 
diff --git a/engines/sci/event.cpp b/engines/sci/event.cpp
index cdddb26ca4..ed9c4bfd0d 100644
--- a/engines/sci/event.cpp
+++ b/engines/sci/event.cpp
@@ -319,8 +319,14 @@ sciEvent EventManager::get(unsigned int mask) {
 	//sci_event_t error_event = { SCI_EVT_ERROR, 0, 0, 0 };
 	sciEvent event = { 0, 0, 0, 0 };
 
-	// Update the screen here, since it's called very often
-	g_system->updateScreen();
+	// Update the screen here, since it's called very often.
+	// Throttle the screen update rate to 60fps.
+	uint32 curTime = g_system->getMillis();
+	uint32 duration = curTime - g_sci->getEngineState()->_screenUpdateTime;
+	if (duration >= 1000 / 60) {
+		g_system->updateScreen();
+		g_sci->getEngineState()->_screenUpdateTime = g_system->getMillis();
+	}
 
 	// Get all queued events from graphics driver
 	do {
diff --git a/engines/sci/sci.cpp b/engines/sci/sci.cpp
index 9e928b82d9..ee2f5845a2 100644
--- a/engines/sci/sci.cpp
+++ b/engines/sci/sci.cpp
@@ -325,7 +325,7 @@ bool SciEngine::initGame() {
 		_vocabulary->parser_base = make_reg(_gamestate->_segMan->getSysStringsSegment(), SYS_STRING_PARSER_BASE);
 	}
 
-	_gamestate->gameStartTime = _gamestate->lastWaitTime = g_system->getMillis();
+	_gamestate->gameStartTime = _gamestate->lastWaitTime = _gamestate->_screenUpdateTime = g_system->getMillis();
 
 	srand(g_system->getMillis()); // Initialize random number generator
 
-- 
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