Replace "frameSwapInterval" setting with "frameRateLimit".

include/settings.hpp

@@ -67,7 +67,8 @@ extern bool tooltips;
 extern bool cpuMeter;
 extern bool lockModules;
 extern bool squeezeModules;
-extern int frameSwapInterval;
+/** Maximum screen redraw frequency in Hz, or 0 for unlimited. */
+extern float frameRateLimit;
 extern float autosaveInterval;
 extern bool skipLoadOnLaunch;
 extern std::list<std::string> recentPatchPaths;

src/app/MenuBar.cpp

@@ -409,13 +409,12 @@ struct ViewButton : MenuButton {
 			APP->window->setFullScreen(!fullscreen);
 		}));
 
-		double frameRate = APP->window->getMonitorRefreshRate() / settings::frameSwapInterval;
-		menu->addChild(createSubmenuItem("Frame rate", string::f("%.0f Hz", frameRate), [=](ui::Menu* menu) {
+		menu->addChild(createSubmenuItem("Frame rate", string::f("%.0f Hz", settings::frameRateLimit), [=](ui::Menu* menu) {
 			for (int i = 1; i <= 6; i++) {
 				double frameRate = APP->window->getMonitorRefreshRate() / i;
 				menu->addChild(createCheckMenuItem(string::f("%.0f Hz", frameRate), "",
-					[=]() {return settings::frameSwapInterval == i;},
-					[=]() {settings::frameSwapInterval = i;}
+					[=]() {return settings::frameRateLimit == frameRate;},
+					[=]() {settings::frameRateLimit = frameRate;}
 				));
 			}
 		}));

src/settings.cpp

@@ -42,10 +42,10 @@ bool cpuMeter = false;
 bool lockModules = false;
 bool squeezeModules = true;
 #if defined ARCH_MAC
-	// Most Mac GPUs can't handle rendering the screen every frame, so use ~30 Hz by default.
-	int frameSwapInterval = 2;
+	// Most Mac GPUs can't handle rendering the screen every frame, so use 30 Hz by default.
+	float frameRateLimit = 30.f;
 #else
-	int frameSwapInterval = 1;
+	float frameRateLimit = 60.f;
 #endif
 float autosaveInterval = 15.0;
 bool skipLoadOnLaunch = false;
@@ -158,7 +158,7 @@ json_t* toJson() {
 
 	json_object_set_new(rootJ, "squeezeModules", json_boolean(squeezeModules));
 
-	json_object_set_new(rootJ, "frameSwapInterval", json_integer(frameSwapInterval));
+	json_object_set_new(rootJ, "frameRateLimit", json_real(frameRateLimit));
 
 	json_object_set_new(rootJ, "autosaveInterval", json_real(autosaveInterval));
 
@@ -347,9 +347,20 @@ void fromJson(json_t* rootJ) {
 	if (squeezeModulesJ)
 		squeezeModules = json_boolean_value(squeezeModulesJ);
 
+	// Legacy setting in Rack <2.2
 	json_t* frameSwapIntervalJ = json_object_get(rootJ, "frameSwapInterval");
-	if (frameSwapIntervalJ)
-		frameSwapInterval = json_integer_value(frameSwapIntervalJ);
+	if (frameSwapIntervalJ) {
+		// Assume 60 Hz monitor refresh rate.
+		int frameSwapInterval = json_integer_value(frameSwapIntervalJ);
+		if (frameSwapInterval > 0)
+			frameRateLimit = 60.f / frameSwapInterval;
+		else
+			frameRateLimit = 0.f;
+	}
+
+	json_t* frameRateLimitJ = json_object_get(rootJ, "frameRateLimit");
+	if (frameRateLimitJ)
+		frameRateLimit = json_number_value(frameRateLimitJ);
 
 	json_t* autosaveIntervalJ = json_object_get(rootJ, "autosaveInterval");
 	if (autosaveIntervalJ)

src/window/Window.cpp

@@ -89,8 +89,8 @@ struct Window::Internal {
 
 	int frame = 0;
 	bool ignoreNextMouseDelta = false;
-	int frameSwapInterval = -1;
 	double monitorRefreshRate = 0.0;
+	int frameSwapInterval = -1;
 	double frameTime = 0.0;
 	double lastFrameDuration = 0.0;
 
@@ -298,7 +298,6 @@ Window::Window() {
 	glfwSetInputMode(win, GLFW_LOCK_KEY_MODS, 1);
 
 	glfwMakeContextCurrent(win);
-	glfwSwapInterval(1);
 	const GLFWvidmode* monitorMode = glfwGetVideoMode(glfwGetPrimaryMonitor());
 	if (monitorMode->refreshRate > 0) {
 		internal->monitorRefreshRate = monitorMode->refreshRate;
@@ -433,9 +432,16 @@ void Window::step() {
 
 	// In case glfwPollEvents() sets another OpenGL context
 	glfwMakeContextCurrent(win);
-	if (settings::frameSwapInterval != internal->frameSwapInterval) {
-		glfwSwapInterval(settings::frameSwapInterval);
-		internal->frameSwapInterval = settings::frameSwapInterval;
+
+	// Set swap interval
+	int frameSwapInterval = 0;
+	if (settings::frameRateLimit > 0.f) {
+		frameSwapInterval = std::ceil(internal->monitorRefreshRate / settings::frameRateLimit);
+	}
+
+	if (frameSwapInterval != internal->frameSwapInterval) {
+		glfwSwapInterval(frameSwapInterval);
+		internal->frameSwapInterval = frameSwapInterval;
 	}
 
 	// Call cursorPosCallback every frame, not just when the mouse moves
@@ -711,7 +717,7 @@ double Window::getLastFrameDuration() {
 
 
 double Window::getFrameDurationRemaining() {
-	double frameDurationDesired = internal->frameSwapInterval / internal->monitorRefreshRate;
+	double frameDurationDesired = 1.f / settings::frameRateLimit;
 	return frameDurationDesired - (system::getTime() - internal->frameTime);
 }