Fix stuttering animations when using high frame rate limit or vsync

client/gui/FramerateManager.cpp

@@ -12,27 +12,36 @@
 #include "FramerateManager.h"
 
 #include "../../lib/CConfigHandler.h"
+#include <SDL_video.h>
 
 FramerateManager::FramerateManager(int targetFrameRate)
-	: targetFrameTime(Duration(boost::chrono::seconds(1)) / targetFrameRate)
-	, lastFrameIndex(0)
+	: lastFrameIndex(0)
 	, lastFrameTimes({})
 	, lastTimePoint(Clock::now())
 	, vsyncEnabled(settings["video"]["vsync"].Bool())
 {
+	if(vsyncEnabled)
+	{
+		static int display_in_use = 0;
+		SDL_DisplayMode mode;
+		SDL_GetCurrentDisplayMode(display_in_use, &mode);
+		int displayRefreshRate = mode.refresh_rate;
+		logGlobal->info("Display refresh rate is %d", displayRefreshRate);
+		targetFrameTime = Duration(boost::chrono::seconds(1)) / displayRefreshRate;
+	} else
+	{
+		targetFrameTime = Duration(boost::chrono::seconds(1)) / targetFrameRate;
+	}
 	boost::range::fill(lastFrameTimes, targetFrameTime);
 }
 
 void FramerateManager::framerateDelay()
 {
-	if(!vsyncEnabled)
-	{
-		Duration timeSpentBusy = Clock::now() - lastTimePoint;
+	Duration timeSpentBusy = Clock::now() - lastTimePoint;
 
-		// FPS is higher than it should be, then wait some time
-		if(timeSpentBusy < targetFrameTime)
-			boost::this_thread::sleep_for(targetFrameTime - timeSpentBusy);
-	}
+	// FPS is higher than it should be, then wait some time
+	if(timeSpentBusy < targetFrameTime)
+		boost::this_thread::sleep_for(targetFrameTime - timeSpentBusy);
 
 	// compute actual timeElapsed taking into account actual sleep interval
 	// limit it to 100 ms to avoid breaking animation in case of huge lag (e.g. triggered breakpoint)