AGI: Kill the timer based counter

Using the timer mechanism for just a simple counter is not just
overkill, its also inaccurate. When using a call frequency of x,
and waiting for y callbacks, the passed time will not be x*y.
The problem amplifies on slower platforms and/or fair thread
schedulers.
Use absolute times instead. Most notably, the walking speed of
the avatar is now smooth on android, but probably on all other
handhelds we support too.

3 files changed, 6 insertions, 25 deletions

diff --git a/engines/agi/agi.cpp b/engines/agi/agi.cpp
index fdc05f0ba9..c5a1f81af6 100644
--- a/engines/agi/agi.cpp
+++ b/engines/agi/agi.cpp
@@ -273,23 +273,16 @@ void AgiEngine::processEvents() {
 }
 
 void AgiEngine::pollTimer() {
-	uint32 dm;
+	_lastTick += 50;
 
-	if (_tickTimer < _lastTickTimer)
-		_lastTickTimer = 0;
-
-	while ((dm = _tickTimer - _lastTickTimer) < 5) {
+	while (_system->getMillis() < _lastTick) {
 		processEvents();
 		_console->onFrame();
 		_system->delayMillis(10);
 		_system->updateScreen();
 	}
-	_lastTickTimer = _tickTimer;
-}
 
-void AgiEngine::agiTimerFunctionLow(void *refCon) {
-	AgiEngine *self = (AgiEngine *)refCon;
-	self->_tickTimer++;
+	_lastTick = _system->getMillis();
 }
 
 void AgiEngine::pause(uint32 msec) {
@@ -532,9 +525,6 @@ AgiEngine::AgiEngine(OSystem *syst, const AGIGameDescription *gameDesc) : AgiBas
 
 	_allowSynthetic = false;
 
-	_tickTimer = 0;
-	_lastTickTimer = 0;
-
 	_intobj = NULL;
 
 	_menu = NULL;
@@ -646,11 +636,10 @@ void AgiEngine::initialize() {
 
 	_lastSaveTime = 0;
 
-	_timer->installTimerProc(agiTimerFunctionLow, 10 * 1000, this);
+	_lastTick = _system->getMillis();
 
 	debugC(2, kDebugLevelMain, "Detect game");
 
-
 	if (agiDetectGame() == errOK) {
 		_game.state = STATE_LOADED;
 		debugC(2, kDebugLevelMain, "game loaded");
@@ -662,8 +651,6 @@ void AgiEngine::initialize() {
 }
 
 AgiEngine::~AgiEngine() {
-	_timer->removeTimerProc(agiTimerFunctionLow);
-
 	// If the engine hasn't been initialized yet via AgiEngine::initialize(), don't attempt to free any resources,
 	// as they haven't been allocated. Fixes bug #1742432 - AGI: Engine crashes if no game is detected
 	if (_game.state == STATE_INIT) {
@@ -719,7 +706,7 @@ void AgiEngine::parseFeatures() {
 	/* FIXME: Seems this method doesn't really do anything. It might
 	   be a leftover that could be removed, except that some of its
 	   intended purpose may still need to be reimplemented.
-	   
+
 	[0:29] <Fingolfin> can you tell me what the point behind AgiEngine::parseFeatures() is?
 	[0:30] <_sev> when games are created with WAGI studio
 	[0:31] <_sev> it creates .wag site with game-specific features such as full game title, whether to use AGIMOUSE etc
diff --git a/engines/agi/agi.h b/engines/agi/agi.h
index 89b116daec..df19f55b52 100644
--- a/engines/agi/agi.h
+++ b/engines/agi/agi.h
@@ -810,9 +810,7 @@ public:
 	Common::Error saveGameState(int slot, const char *desc);
 
 private:
-
-	uint32 _tickTimer;
-	uint32 _lastTickTimer;
+	uint32 _lastTick;
 
 	int _keyQueue[KEY_QUEUE_SIZE];
 	int _keyQueueStart;
@@ -883,7 +881,6 @@ public:
 	virtual bool isKeypress();
 	virtual void clearKeyQueue();
 
-	static void agiTimerFunctionLow(void *refCon);
 	void initPriTable();
 
 	void newInputMode(InputMode mode);
diff --git a/engines/agi/preagi.cpp b/engines/agi/preagi.cpp
index fe864d7659..1aa6ef5cc4 100644
--- a/engines/agi/preagi.cpp
+++ b/engines/agi/preagi.cpp
@@ -122,9 +122,6 @@ void PreAgiEngine::initialize() {
 	_mixer->playStream(Audio::Mixer::kSFXSoundType, &_speakerHandle,
 							_speakerStream, -1, Audio::Mixer::kMaxChannelVolume, 0, DisposeAfterUse::NO, true);
 
-
-	//_timer->installTimerProc(agiTimerFunctionLow, 10 * 1000, NULL);
-
 	debugC(2, kDebugLevelMain, "Detect game");
 
 	// clear all resources and events