FLTK: Better frame timing

source/fltkui/fltkui.cpp

@@ -55,6 +55,7 @@ static Fl_Menu_Bar *menubar;
 static NstGlArea *glarea;
 static NstChtWindow *chtwin;
 static NstConfWindow *confwin;
+static int fps = 60;
 
 extern int loaded;
 
@@ -69,6 +70,22 @@ extern nstpaths_t nstpaths;
 
 extern bool (*nst_archive_select)(const char*, char*, size_t);
 
+static int fltkui_refreshrate(void) {
+	// Get the screen refresh rate using an SDL window
+	int refresh = 60;
+	SDL_Window *sdlwin;
+	sdlwin = SDL_CreateWindow(
+		"refreshrate",
+		SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
+		1, 1, SDL_WINDOW_HIDDEN
+	);
+	SDL_DisplayMode dm;
+	SDL_GetCurrentDisplayMode(SDL_GetWindowDisplayIndex(sdlwin), &dm);
+	refresh = dm.refresh_rate;
+	SDL_DestroyWindow(sdlwin);
+	return refresh;
+}
+
 static void fltkui_cheats(Fl_Widget* w, void* userdata) {
 	if (!loaded) { return; }
 	chtwin->refresh();
@@ -94,7 +111,10 @@ static void fltkui_rom_open(Fl_Widget* w, void* userdata) {
 			if (fc.filename()) {
 				loaded = nst_load(fc.filename());
 				nstwin->label(nstpaths.gamename);
-				if (loaded) { nst_play(); }
+				if (loaded) {
+					nst_play();
+					fps = nst_pal() ? 50 : 60;
+				}
 			}
 			break;
 	}
@@ -463,11 +483,13 @@ int main(int argc, char *argv[]) {
 	nst_set_callbacks();
 
 	// Initialize SDL Audio and Joystick
-	if (SDL_Init(SDL_INIT_AUDIO | SDL_INIT_JOYSTICK) < 0) {
+	if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_JOYSTICK) < 0) {
 		fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError());
 		return 1;
 	}
 
+	int refreshrate = fltkui_refreshrate();
+
 	// Set archive handler function pointer
 	nst_archive_select = &fltkui_archive_select;
 
@@ -507,6 +529,10 @@ int main(int argc, char *argv[]) {
 
 	video_init();
 
+	int frames = 0;
+	int framefrags = 0;
+	fps = nst_pal() ? 50 : 60;
+
 	while (true) {
 		Fl::check();
 		if (!nstwin->shown()) {
@@ -528,7 +554,15 @@ int main(int argc, char *argv[]) {
 			}
 		}
 
-		nst_emuloop();
+		frames = (fps / refreshrate);
+		framefrags += fps % refreshrate;
+
+		if (framefrags >= refreshrate) {
+			frames++;
+			framefrags -= refreshrate;
+		}
+
+		for (int i = 0; i < frames; i++) { nst_emuloop(); }
 		glarea->redraw();
 	}
 

source/fltkui/nstcommon.cpp

@@ -806,12 +806,6 @@ void nst_state_quickload(int slot) {
 	nst_state_load(slotpath);
 }
 
-int nst_timing_runframes() {
-	// Calculate how many emulation frames to run
-	if (ffspeed) { return conf.timing_ffspeed; }
-	return 1;
-}
-
 void nst_timing_set_ffspeed() {
 	// Set the framerate to the fast-forward speed
 	ffspeed = true;
@@ -847,7 +841,7 @@ void nst_emuloop() {
 		nst_input_turbo_pulse(cNstPads);
 
 		// Execute frames
-		for (int i = 0; i < nst_timing_runframes(); i++) {
+		for (int i = 0; i < (ffspeed ? conf.timing_ffspeed : 1); i++) {
 			emulator.Execute(cNstVideo, cNstSound, cNstPads);
 		}
 	}

source/fltkui/nstcommon.h

@@ -93,7 +93,6 @@ void nst_state_quicksave(int isvst);
 void nst_state_quickload(int isvst);
 
 // Timing
-int nst_timing_runframes();
 void nst_timing_set_ffspeed();
 void nst_timing_set_default();