Qt: Ability to cap fast forward speed (fixes B#218)

CHANGES

@@ -17,6 +17,7 @@ Features:
  - Screensaver can now be suspended while a game is running
  - Load/save the most recent savestate slot
  - Support varible speed (PWM) rumble
+ - Ability to cap fast forward speed
 Bugfixes:
  - ARM7: Fix SWI and IRQ timings
  - GBA Audio: Force audio FIFOs to 32-bit

src/platform/qt/GameController.cpp

@@ -41,8 +41,10 @@ GameController::GameController(QObject* parent)
 	, m_audioProcessor(AudioProcessor::create())
 	, m_videoSync(VIDEO_SYNC)
 	, m_audioSync(AUDIO_SYNC)
+	, m_fpsTarget(-1)
 	, m_turbo(false)
 	, m_turboForced(false)
+	, m_turboSpeed(-1)
 	, m_inputController(nullptr)
 	, m_multiplayer(nullptr)
 	, m_stateSlot(1)
@@ -99,6 +101,7 @@ GameController::GameController(QObject* parent)
 		context->gba->rtcSource = &controller->m_rtc;
 		context->gba->rumble = controller->m_inputController->rumble();
 		context->gba->rotationSource = controller->m_inputController->rotationSource();
+		controller->m_fpsTarget = context->fpsTarget;
 		controller->gameStarted(context);
 	};
 
@@ -487,7 +490,11 @@ void GameController::setAudioBufferSamples(int samples) {
 
 void GameController::setFPSTarget(float fps) {
 	threadInterrupt();
+	m_fpsTarget = fps;
 	m_threadContext.fpsTarget = fps;
+	if (m_turbo && m_turboSpeed > 0) {
+		m_threadContext.fpsTarget *= m_turboSpeed;
+	}
 	redoSamples(m_audioProcessor->getBufferSamples());
 	threadContinue();
 	QMetaObject::invokeMethod(m_audioProcessor, "inputParametersChanged");
@@ -577,9 +584,30 @@ void GameController::setTurbo(bool set, bool forced) {
 	}
 	m_turbo = set;
 	m_turboForced = set && forced;
+	enableTurbo();
+}
+
+void GameController::setTurboSpeed(float ratio) {
+	m_turboSpeed = ratio;
+	enableTurbo();
+}
+
+void GameController::enableTurbo() {
 	threadInterrupt();
-	m_threadContext.sync.audioWait = set ? false : m_audioSync;
+	if (!m_turbo) {
-	m_threadContext.sync.videoFrameWait = set ? false : m_videoSync;
+		m_threadContext.fpsTarget = m_fpsTarget;
+		m_threadContext.sync.audioWait = m_audioSync;
+		m_threadContext.sync.videoFrameWait = m_videoSync;
+		redoSamples(m_audioProcessor->getBufferSamples());
+	} else if (m_turboSpeed <= 0) {
+		m_threadContext.sync.audioWait = false;
+		m_threadContext.sync.videoFrameWait = false;
+	} else {
+		m_threadContext.fpsTarget = m_fpsTarget * m_turboSpeed;
+		m_threadContext.sync.audioWait = true;
+		m_threadContext.sync.videoFrameWait = false;
+		redoSamples(m_audioProcessor->getBufferSamples());
+	}
 	threadContinue();
 }
 

src/platform/qt/GameController.h

@@ -121,6 +121,7 @@ public slots:
 	void setVolume(int);
 	void setMute(bool);
 	void setTurbo(bool, bool forced = true);
+	void setTurboSpeed(float ratio = -1);
 	void setAVStream(GBAAVStream*);
 	void clearAVStream();
 	void reloadAudioDriver();
@@ -151,6 +152,7 @@ private slots:
 private:
 	void updateKeys();
 	void redoSamples(int samples);
+	void enableTurbo();
 
 	uint32_t* m_drawContext;
 	GBAThread m_threadContext;
@@ -177,8 +179,10 @@ private:
 
 	bool m_videoSync;
 	bool m_audioSync;
+	float m_fpsTarget;
 	bool m_turbo;
 	bool m_turboForced;
+	float m_turboSpeed;
 
 	int m_stateSlot;
 

src/platform/qt/Window.cpp

@@ -787,6 +787,19 @@ void Window::setupMenu(QMenuBar* menubar) {
 	connect(turbo, SIGNAL(triggered(bool)), m_controller, SLOT(setTurbo(bool)));
 	addControlledAction(emulationMenu, turbo, "fastForward");
 
+	QMenu* ffspeedMenu = emulationMenu->addMenu(tr("Fast forward speed"));
+	ConfigOption* ffspeed = m_config->addOption("fastForwardRatio");
+	ffspeed->connect([this](const QVariant& value) {
+		m_controller->setTurboSpeed(value.toFloat());
+	}, this);
+	ffspeed->addValue(tr("Unbounded"), -1.0f, ffspeedMenu);
+	ffspeed->setValue(QVariant(-1.0f));
+	ffspeedMenu->addSeparator();
+	for (i = 2; i < 6; ++i) {
+		ffspeed->addValue(tr("%0x").arg(i), i, ffspeedMenu);
+	}
+	m_config->updateOption("fastForwardRatio");
+
 	QAction* rewind = new QAction(tr("Re&wind"), emulationMenu);
 	rewind->setShortcut(tr("`"));
 	connect(rewind, SIGNAL(triggered()), m_controller, SLOT(rewind()));