PEGASUS: Implement dirty rect erase code (as used by the space chase)

engines/pegasus/graphics.cpp

@@ -45,6 +45,7 @@ GraphicsManager::GraphicsManager(PegasusEngine *vm) : _vm(vm) {
 	_workArea.create(640, 480, _vm->_system->getScreenFormat());
 	_modifiedScreen = false;
 	_curSurface = &_workArea;
+	_erase = false;
 }
 
 GraphicsManager::~GraphicsManager() {
@@ -150,6 +151,10 @@ void GraphicsManager::updateDisplay() {
 	bool screenDirty = false;
 
 	if (!_dirtyRect.isEmpty()) {
+		// Fill the dirty area with black if erase mode is enabled
+		if (_erase)
+			_workArea.fillRect(_dirtyRect, _workArea.format.RGBToColor(0, 0, 0));
+
 		for (DisplayElement *runner = _firstDisplayElement; runner != 0; runner = runner->_nextElement) {
 			Common::Rect bounds;
 			runner->getBounds(bounds);
@@ -320,5 +325,13 @@ void GraphicsManager::shakeTheWorld(TimeValue duration, TimeScale scale) {
 
 	oldScreen.free();
 }
+
+void GraphicsManager::enableErase() {
+	_erase = true;
+}
+
+void GraphicsManager::disableErase() {
+	_erase = false;
+}
 
 } // End of namespace Pegasus

engines/pegasus/graphics.h

@@ -60,6 +60,8 @@ friend class Cursor;
 	void clearScreen();
 	DisplayElement *findDisplayElement(const tDisplayElementID id);
 	void shakeTheWorld(TimeValue time, TimeScale scale);
+	void enableErase();
+	void disableErase();
 
 	// These default to black
 	void doFadeOutSync(const TimeValue = kOneSecondPerThirtyTicks, const TimeScale = kThirtyTicksPerSecond, uint32 color = 0);
@@ -71,7 +73,7 @@ friend class Cursor;
 private:		
 	PegasusEngine *_vm;
 
-	bool _modifiedScreen;
+	bool _modifiedScreen, _erase;
 	Common::Rect _dirtyRect;
 	tDisplayOrder _backLayer, _frontLayer;
 	DisplayElement *_firstDisplayElement, *_lastDisplayElement;

engines/pegasus/neighborhood/mars/mars.cpp

@@ -2822,6 +2822,8 @@ void Mars::marsTimerExpired(MarsTimerEvent &event) {
 		_canyonChaseMovie.stopDisplaying();
 		_canyonChaseMovie.releaseMovie();
 
+		_vm->_gfx->enableErase();
+
 		loadLoopSound1("Sounds/Mars/Space Ambient.22K.8.AIFF");
 
 		playSpotSoundSync(kShuttleConfiguringIn, kShuttleConfiguringOut);