implemented drawing of additional scrolling frames

svn-id: r12223

3 files changed, 38 insertions, 7 deletions

diff --git a/sword1/screen.cpp b/sword1/screen.cpp
index ce80b3298c..2f3915ba19 100644
--- a/sword1/screen.cpp
+++ b/sword1/screen.cpp
@@ -119,6 +119,21 @@ bool SwordScreen::stillFading(void) {
 	return (_fadingStep != 0);
 }
 
+bool SwordScreen::showScrollFrame(void) {
+	if ((!_fullRefresh) || SwordLogic::_scriptVars[NEW_PALETTE] || (!SwordLogic::_scriptVars[SCROLL_FLAG]))
+		return false; // don't draw an additional frame if we aren't scrolling or have to change the palette
+	if ((_oldScrollX == SwordLogic::_scriptVars[SCROLL_OFFSET_X]) &&
+		(_oldScrollY == SwordLogic::_scriptVars[SCROLL_OFFSET_Y]))
+		return false; // check again if we *really* are scrolling.
+
+	uint16 avgScrlX = (uint16)(_oldScrollX + SwordLogic::_scriptVars[SCROLL_OFFSET_X]) / 2;
+	uint16 avgScrlY = (uint16)(_oldScrollY + SwordLogic::_scriptVars[SCROLL_OFFSET_Y]) / 2;
+
+	_system->copy_rect(_screenBuf + avgScrlY * _scrnSizeX + avgScrlX, _scrnSizeX, 0, 40, SCREEN_WIDTH, SCREEN_DEPTH);
+	_system->update_screen();
+	return true;
+}
+
 void SwordScreen::updateScreen(void) {
 	if (SwordLogic::_scriptVars[NEW_PALETTE]) {
 		_fadingStep = 1;
@@ -653,7 +668,9 @@ void SwordScreen::decompressRLE0(uint8 *src, uint32 compSize, uint8 *dest) {
 void SwordScreen::fadePalette(void) {
 	if (_fadingStep == 16)
 		memcpy(_currentPalette, _targetPalette, 256 * 4);
-	else
+	else if ((_fadingStep == 1) && (_fadingDirection == FADE_DOWN)) {
+		memset(_currentPalette, 0, 4 * 256);
+	} else
 		for (uint16 cnt = 0; cnt < 256 * 4; cnt++)
 			_currentPalette[cnt] = (_targetPalette[cnt] * _fadingStep) >> 4;
 
diff --git a/sword1/screen.h b/sword1/screen.h
index 8abe94a95b..741eb4992f 100644
--- a/sword1/screen.h
+++ b/sword1/screen.h
@@ -80,6 +80,7 @@ public:
 	bool stillFading(void);
 	void fullRefresh(void);
 
+	bool showScrollFrame(void);
 	void updateScreen(void);
 	void showFrame(uint16 x, uint16 y, uint32 resId, uint32 frameNo, const byte *fadeMask = NULL, int8 fadeStatus = 0);
 
diff --git a/sword1/sword1.cpp b/sword1/sword1.cpp
index ce2d9db887..6adba5702d 100644
--- a/sword1/sword1.cpp
+++ b/sword1/sword1.cpp
@@ -1119,6 +1119,7 @@ void SwordEngine::checkCd(void) {
 
 uint8 SwordEngine::mainLoop(void) {
 	uint8 retCode = 0;
+	_keyPressed = 0;
 
 	while (retCode == 0) {
 		// do we need the section45-hack from sword.c here?
@@ -1130,6 +1131,9 @@ uint8 SwordEngine::mainLoop(void) {
 		SwordLogic::_scriptVars[SCREEN] = SwordLogic::_scriptVars[NEW_SCREEN];
 		
 		do {
+			uint32 newTime;
+			bool scrollFrameShown = false;
+
 			uint32 frameTime = _system->get_msecs();
 			_logic->engine();
 			_logic->updateScreenParams(); // sets scrolling
@@ -1138,15 +1142,24 @@ uint8 SwordEngine::mainLoop(void) {
 			_mouse->animate();
 
 			_sound->engine();
-			_screen->updateScreen();
-
 			_menu->refresh(MENU_TOP);
 			_menu->refresh(MENU_BOT);
 
-			uint32 newTime = _system->get_msecs();
+			newTime = _system->get_msecs();
+			if (newTime - frameTime < 1000 / FRAME_RATE) {
+				scrollFrameShown = _screen->showScrollFrame();
+				int32 restDelay = (1000 / (FRAME_RATE * 2)) - (_system->get_msecs() - frameTime);
+                if (restDelay > 0)
+					delay((uint)restDelay);
+			}
 
-			if (newTime - frameTime < 80)
-				delay(80 - (newTime - frameTime));
+			newTime = _system->get_msecs();
+			if ((newTime - frameTime < 1000 / FRAME_RATE) || (!scrollFrameShown))
+				_screen->updateScreen();
+
+			int32 frameDelay = (1000 / FRAME_RATE) - (_system->get_msecs() - frameTime);
+			if (frameDelay > 0)
+				delay((uint)frameDelay);
 			else
 				delay(0);
 
@@ -1160,6 +1173,7 @@ uint8 SwordEngine::mainLoop(void) {
 				if (!retCode)
 					_screen->fullRefresh();
 			}
+			_keyPressed = 0;
 
 			// do something smart here to implement pausing the game. If we even want that, that is.
 		} while ((SwordLogic::_scriptVars[SCREEN] == SwordLogic::_scriptVars[NEW_SCREEN]) && (retCode == 0));
@@ -1185,7 +1199,6 @@ void SwordEngine::delay(uint amount) { //copied and mutilated from sky.cpp
 
 	uint32 start = _system->get_msecs();
 	uint32 cur = start;
-	_keyPressed = 0;
 
 	do {
 		while (_system->poll_event(&event)) {