FINALLY added vsync.

Defaults to on for all platforms except the RPi. Force it off with "--vsync 0".

Will try to use late swap tearing if supported on the current system.

README.md

@@ -111,6 +111,7 @@ You can use `--help` or `-h` to view a list of command-line options. Briefly out
 --no-exit		- do not display 'exit' in the ES menu.
 --debug			- print additional output to the console, primarily about input.
 --windowed	- run ES in a window, works best in conjunction with --resolution [w] [h].
+--vsync [0/1]		- turn vsync on or off (default is on), only works in fullscreen.
 --scrape	- run the interactive command-line metadata scraper.
 ```
 

es-app/src/main.cpp

@@ -57,6 +57,10 @@ bool parseArgs(int argc, char* argv[], unsigned int* width, unsigned int* height
 		}else if(strcmp(argv[i], "--windowed") == 0)
 		{
 			Settings::getInstance()->setBool("Windowed", true);
+		}else if(strcmp(argv[i], "--vsync") == 0)
+		{
+			Settings::getInstance()->setBool("VSync", atoi(argv[i + 1]));
+			i++; // skip vsync value
 		}else if(strcmp(argv[i], "--scrape") == 0)
 		{
 			scrape_cmdline = true;
@@ -75,6 +79,7 @@ bool parseArgs(int argc, char* argv[], unsigned int* width, unsigned int* height
 				"--debug				even more logging\n"
 				"--scrape			scrape using command line interface\n"
 				"--windowed			not fullscreen, should be used with --resolution\n"
+				"--vsync [0/1]		turn vsync on or off (default is on)\n"
 				"--help, -h			summon a sentient, angry tuba\n\n"
 				"More information available in README.md.\n";
 			return false; //exit after printing help

es-core/src/Renderer_init_sdlgl.cpp

@@ -49,7 +49,6 @@ namespace Renderer
 #ifdef USE_OPENGL_ES
 		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 1);
 #endif
-		//SDL_GL_SetSwapInterval(1); //0 for immediate updates, 1 for updates synchronized with the vertical retrace, -1 for late swap tearing
 
 		SDL_DisplayMode dispMode;
 		SDL_GetDesktopDisplayMode(0, &dispMode);
@@ -96,6 +95,19 @@ namespace Renderer
 
 		sdlContext = SDL_GL_CreateContext(sdlWindow);
 
+		// vsync
+		if(Settings::getInstance()->getBool("VSync"))
+		{
+			// SDL_GL_SetSwapInterval(0) for immediate updates (no vsync, default), 
+			// 1 for updates synchronized with the vertical retrace, 
+			// or -1 for late swap tearing.
+			// SDL_GL_SetSwapInterval returns 0 on success, -1 on error.
+			// if vsync is requested, try late swap tearing; if that doesn't work, try normal vsync
+			// if that doesn't work, report an error
+			if(SDL_GL_SetSwapInterval(-1) != 0 && SDL_GL_SetSwapInterval(1) != 0)
+				LOG(LogWarning) << "Tried to enable vsync, but failed! (" << SDL_GetError() << ")";
+		}
+
 		//hide mouse cursor
 		initialCursorState = SDL_ShowCursor(0) == 1;
 

es-core/src/Settings.cpp

@@ -16,6 +16,7 @@ std::vector<const char*> settings_dont_save = boost::assign::list_of
 	("ParseGamelistOnly")
 	("ShowExit")
 	("Windowed")
+	("VSync")
 	("IgnoreGamelist");
 
 Settings::Settings()
@@ -41,6 +42,15 @@ void Settings::setDefaults()
 	mBoolMap["DrawFramerate"] = false;
 	mBoolMap["ShowExit"] = true;
 	mBoolMap["Windowed"] = false;
+
+#ifdef _RPI_
+	// don't enable VSync by default on the Pi, since it already 
+	// has trouble trying to render things at 60fps in certain menus
+	mBoolMap["VSync"] = false;
+#else
+	mBoolMap["VSync"] = true;
+#endif
+
 	mBoolMap["EnableSounds"] = true;
 	mBoolMap["ShowHelpPrompts"] = true;
 	mBoolMap["ScrapeRatings"] = true;