GBA: Revamp frameskip

src/gba/context/context.c

@@ -60,7 +60,7 @@ bool GBAContextInit(struct GBAContext* context, const char* port) {
 		GBAConfigLoadDefaults(&context->config, &opts);
 	}
 
-	context->gba->sync = &context->sync;
+	context->gba->sync = 0;
 	return true;
 }
 
@@ -191,11 +191,6 @@ void GBAContextFrame(struct GBAContext* context, uint16_t keys) {
 	while (frameCounter == context->gba->video.frameCounter) {
 		ARMRunLoop(context->cpu);
 	}
-	if (context->sync.videoFrameSkip < 0) {
-		int frameskip = 0;
-		GBAConfigGetIntValue(&context->config, "frameskip", &frameskip);
-		context->sync.videoFrameSkip = frameskip;
-	}
 }
 
 static void _GBAContextLog(struct GBAThread* thread, enum GBALogLevel level, const char* format, va_list args) {

src/gba/context/context.h

@@ -24,7 +24,6 @@ struct GBAContext {
 	struct GBAConfig config;
 	struct GBAOptions opts;
 	struct GBAInputMap inputMap;
-	struct GBASync sync;
 };
 
 bool GBAContextInit(struct GBAContext* context, const char* port);

src/gba/context/sync.c

@@ -22,15 +22,12 @@ void GBASyncPostFrame(struct GBASync* sync) {
 
 	MutexLock(&sync->videoFrameMutex);
 	++sync->videoFramePending;
-	--sync->videoFrameSkip;
-	if (sync->videoFrameSkip < 0) {
 	do {
 		ConditionWake(&sync->videoFrameAvailableCond);
 		if (sync->videoFrameWait) {
 			ConditionWait(&sync->videoFrameRequiredCond, &sync->videoFrameMutex);
 		}
 	} while (sync->videoFrameWait && sync->videoFramePending);
-	}
 	MutexUnlock(&sync->videoFrameMutex);
 }
 
@@ -44,7 +41,7 @@ void GBASyncForceFrame(struct GBASync* sync) {
 	MutexUnlock(&sync->videoFrameMutex);
 }
 
-bool GBASyncWaitFrameStart(struct GBASync* sync, int frameskip) {
+bool GBASyncWaitFrameStart(struct GBASync* sync) {
 	if (!sync) {
 		return true;
 	}
@@ -60,7 +57,6 @@ bool GBASyncWaitFrameStart(struct GBASync* sync, int frameskip) {
 		}
 	}
 	sync->videoFramePending = 0;
-	sync->videoFrameSkip = frameskip;
 	return true;
 }
 
@@ -72,14 +68,6 @@ void GBASyncWaitFrameEnd(struct GBASync* sync) {
 	MutexUnlock(&sync->videoFrameMutex);
 }
 
-bool GBASyncDrawingFrame(struct GBASync* sync) {
-	if (!sync) {
-		return true;
-	}
-
-	return sync->videoFrameSkip <= 0;
-}
-
 void GBASyncSetVideoSync(struct GBASync* sync, bool wait) {
 	if (!sync) {
 		return;

src/gba/context/sync.h

@@ -13,7 +13,6 @@
 struct GBASync {
 	int videoFramePending;
 	bool videoFrameWait;
-	int videoFrameSkip;
 	bool videoFrameOn;
 	Mutex videoFrameMutex;
 	Condition videoFrameAvailableCond;
@@ -26,9 +25,8 @@ struct GBASync {
 
 void GBASyncPostFrame(struct GBASync* sync);
 void GBASyncForceFrame(struct GBASync* sync);
-bool GBASyncWaitFrameStart(struct GBASync* sync, int frameskip);
+bool GBASyncWaitFrameStart(struct GBASync* sync);
 void GBASyncWaitFrameEnd(struct GBASync* sync);
-bool GBASyncDrawingFrame(struct GBASync* sync);
 void GBASyncSetVideoSync(struct GBASync* sync, bool wait);
 
 void GBASyncProduceAudio(struct GBASync* sync, bool wait);

src/gba/gui/gui-runner.c

@@ -325,6 +325,7 @@ void GBAGUIRunloop(struct GBAGUIRunner* runner) {
 					break;
 				case RUNNER_CONFIG:
 					GBAGUIShowConfig(runner, runner->configExtra, runner->nConfigExtra);
+					GBAConfigGetIntValue(&runner->context.config, "frameskip", &runner->context.gba->video.frameskip);
 					break;
 				case RUNNER_CONTINUE:
 					break;

src/gba/supervisor/thread.c

@@ -140,6 +140,7 @@ static THREAD_ENTRY _GBAThreadRun(void* context) {
 	gba.logLevel = threadContext->logLevel;
 	gba.logHandler = threadContext->logHandler;
 	gba.stream = threadContext->stream;
+	gba.video.frameskip = threadContext->frameskip;
 
 	struct GBAThreadStop stop;
 	if (threadContext->stopCallback) {
@@ -386,7 +387,6 @@ bool GBAThreadStart(struct GBAThread* threadContext) {
 	threadContext->activeKeys = 0;
 	threadContext->state = THREAD_INITIALIZED;
 	threadContext->sync.videoFrameOn = true;
-	threadContext->sync.videoFrameSkip = 0;
 
 	threadContext->rewindBuffer = 0;
 	threadContext->rewindScreenBuffer = 0;

src/gba/video.c

@@ -59,6 +59,7 @@ static struct GBAVideoRenderer dummyRenderer = {
 void GBAVideoInit(struct GBAVideo* video) {
 	video->renderer = &dummyRenderer;
 	video->vram = 0;
+	video->frameskip = 0;
 }
 
 void GBAVideoReset(struct GBAVideo* video) {
@@ -80,6 +81,7 @@ void GBAVideoReset(struct GBAVideo* video) {
 	video->nextVcounterIRQ = 0;
 
 	video->frameCounter = 0;
+	video->frameskipCounter = 0;
 
 	if (video->vram) {
 		mappedMemoryFree(video->vram, SIZE_VRAM);
@@ -154,7 +156,7 @@ int32_t GBAVideoProcessEvents(struct GBAVideo* video, int32_t cycles) {
 				break;
 			case VIDEO_VERTICAL_PIXELS:
 				video->p->memory.io[REG_DISPSTAT >> 1] = GBARegisterDISPSTATFillInVblank(dispstat);
-				if (GBASyncDrawingFrame(video->p->sync)) {
+				if (video->frameskipCounter <= 0) {
 					video->renderer->finishFrame(video->renderer);
 				}
 				video->nextVblankIRQ = video->nextEvent + VIDEO_TOTAL_LENGTH;
@@ -163,7 +165,10 @@ int32_t GBAVideoProcessEvents(struct GBAVideo* video, int32_t cycles) {
 					GBARaiseIRQ(video->p, IRQ_VBLANK);
 				}
 				GBAFrameEnded(video->p);
-				GBASyncPostFrame(video->p->sync);
+				--video->frameskipCounter;
+				if (video->frameskipCounter < 0) {
+					video->frameskipCounter = video->frameskip;
+				}
 				++video->frameCounter;
 				break;
 			case VIDEO_VERTICAL_TOTAL_PIXELS - 1:
@@ -178,7 +183,7 @@ int32_t GBAVideoProcessEvents(struct GBAVideo* video, int32_t cycles) {
 			video->nextHblank = video->nextEvent + VIDEO_HDRAW_LENGTH;
 			video->nextHblankIRQ = video->nextHblank;
 
-			if (video->vcount < VIDEO_VERTICAL_PIXELS && GBASyncDrawingFrame(video->p->sync)) {
+			if (video->vcount < VIDEO_VERTICAL_PIXELS && video->frameskipCounter <= 0) {
 				video->renderer->drawScanline(video->renderer, video->vcount);
 			}
 

src/gba/video.h

@@ -199,6 +199,8 @@ struct GBAVideo {
 	union GBAOAM oam;
 
 	int32_t frameCounter;
+	int frameskip;
+	int frameskipCounter;
 };
 
 void GBAVideoInit(struct GBAVideo* video);

src/platform/qt/DisplayGL.cpp

@@ -208,7 +208,7 @@ void PainterGL::draw() {
 	if (m_queue.isEmpty()) {
 		return;
 	}
-	if (GBASyncWaitFrameStart(&m_context->sync, m_context->frameskip) || !m_queue.isEmpty()) {
+	if (GBASyncWaitFrameStart(&m_context->sync) || !m_queue.isEmpty()) {
 		dequeue();
 		m_painter.begin(m_gl->context()->device());
 		performDraw();

src/platform/qt/GameController.cpp

@@ -124,12 +124,8 @@ GameController::GameController(QObject* parent)
 
 	m_threadContext.frameCallback = [](GBAThread* context) {
 		GameController* controller = static_cast<GameController*>(context->userData);
-		if (GBASyncDrawingFrame(&controller->m_threadContext.sync)) {
 		memcpy(controller->m_frontBuffer, controller->m_drawContext, 256 * VIDEO_HORIZONTAL_PIXELS * BYTES_PER_PIXEL);
 		QMetaObject::invokeMethod(controller, "frameAvailable", Q_ARG(const uint32_t*, controller->m_frontBuffer));
-		} else {
-			QMetaObject::invokeMethod(controller, "frameAvailable", Q_ARG(const uint32_t*, nullptr));
-		}
 		if (controller->m_pauseAfterFrame.testAndSetAcquire(true, false)) {
 			GBAThreadPauseFromThread(context);
 			QMetaObject::invokeMethod(controller, "gamePaused", Q_ARG(GBAThread*, context));
@@ -773,7 +769,12 @@ void GameController::setAudioSync(bool set) {
 }
 
 void GameController::setFrameskip(int skip) {
+	threadInterrupt();
 	m_threadContext.frameskip = skip;
+	if (m_gameOpen) {
+		m_threadContext.gba->video.frameskip = skip;
+	}
+	threadContinue();
 }
 
 void GameController::setVolume(int volume) {

src/platform/sdl/gl-sdl.c

@@ -61,7 +61,7 @@ void GBASDLGLRunloop(struct GBAThread* context, struct SDLSoftwareRenderer* rend
 #endif
 		}
 
-		if (GBASyncWaitFrameStart(&context->sync, context->frameskip)) {
+		if (GBASyncWaitFrameStart(&context->sync)) {
 			v->postFrame(v, renderer->d.outputBuffer);
 		}
 		v->drawFrame(v);

src/platform/sdl/gles2-sdl.c

@@ -114,7 +114,7 @@ void GBASDLGLES2Runloop(struct GBAThread* context, struct SDLSoftwareRenderer* r
 			GBASDLHandleEvent(context, &renderer->player, &event);
 		}
 
-		if (GBASyncWaitFrameStart(&context->sync, context->frameskip)) {
+		if (GBASyncWaitFrameStart(&context->sync)) {
 			v->postFrame(v, renderer->d.outputBuffer);
 		}
 		v->drawFrame(v);

src/platform/sdl/pandora-sdl.c

@@ -71,7 +71,7 @@ void GBASDLRunloop(struct GBAThread* context, struct SDLSoftwareRenderer* render
 			GBASDLHandleEvent(context, &renderer->player, &event);
 		}
 
-		if (GBASyncWaitFrameStart(&context->sync, context->frameskip)) {
+		if (GBASyncWaitFrameStart(&context->sync)) {
 			int arg = 0;
 			ioctl(renderer->fb, FBIO_WAITFORVSYNC, &arg);
 

src/platform/sdl/sw-sdl.c

@@ -93,7 +93,7 @@ void GBASDLSWRunloop(struct GBAThread* context, struct SDLSoftwareRenderer* rend
 			GBASDLHandleEvent(context, &renderer->player, &event);
 		}
 
-		if (GBASyncWaitFrameStart(&context->sync, context->frameskip)) {
+		if (GBASyncWaitFrameStart(&context->sync)) {
 #if SDL_VERSION_ATLEAST(2, 0, 0)
 			SDL_UnlockTexture(renderer->sdlTex);
 			SDL_RenderCopy(renderer->sdlRenderer, renderer->sdlTex, 0, 0);

src/platform/test/perf-main.c

@@ -167,7 +167,7 @@ static void _GBAPerfRunloop(struct GBAThread* context, int* frames, bool quiet)
 	*frames = 0;
 	int lastFrames = 0;
 	while (context->state < THREAD_EXITING) {
-		if (GBASyncWaitFrameStart(&context->sync, 0)) {
+		if (GBASyncWaitFrameStart(&context->sync)) {
 			++*frames;
 			++lastFrames;
 			if (!quiet) {