PEGASUS: Fix startFaderSync

Since we're not running in multiple threads anymore, we cannot have the fader hold the main thread to itself.

engines/pegasus/fader.cpp

@@ -31,6 +31,7 @@ namespace Pegasus {
 Fader::Fader() {
 	_currentValue = 0;
 	_currentFaderMove._numKnots = 0;
+	_syncMode = false;
 }
 
 void Fader::setFaderValue(const uint32 newValue) {
@@ -85,19 +86,13 @@ void Fader::startFader(const FaderMoveSpec &spec) {
 
 void Fader::startFaderSync(const FaderMoveSpec &spec) {
 	if (initFaderMove(spec)) {
+		_syncMode = true;
+
 		setFlags(0);
 		setScale(spec._faderScale);
 		setSegment(spec._knots[0].knotTime, spec._knots[spec._numKnots - 1].knotTime);
 		setTime(spec._knots[0].knotTime);
-		start();
-
-		while (isFading())
-			useIdleTime();
-
-		// Once more, for good measure, to make sure that there are no boundary
-		// condition problems.
-		useIdleTime();
-		stopFader();
+		start();		
 	}
 }
 
@@ -144,6 +139,18 @@ void Fader::timeChanged(const TimeValue newTime) {
 	}
 }
 
+void Fader::checkCallBacks() {
+	IdlerTimeBase::checkCallBacks();
+
+	if (_syncMode && !isRunning()) {
+		// Once more, for good measure, to make sure that there are no boundary
+		// condition problems.
+		useIdleTime();
+		stopFader();
+		_syncMode = false;
+	}
+}
+
 void FaderMoveSpec::makeOneKnotFaderSpec(const uint32 knotValue) {
 	_numKnots = 1;
 	_knots[0].knotTime = 0;

engines/pegasus/fader.h

@@ -89,12 +89,15 @@ class Fader : public IdlerTimeBase {
 
 	void getCurrentFaderMove(FaderMoveSpec &spec) { spec = _currentFaderMove; }
 
+	virtual void checkCallBacks();
+
 protected:
 	bool initFaderMove(const FaderMoveSpec &);
 	virtual void timeChanged(const TimeValue);
 
 	uint32 _currentValue;
 	FaderMoveSpec _currentFaderMove;
+	bool _syncMode;
 };
 
 class FaderAnimation : public DisplayElement, public Fader {