Make FPS counter a little more accurate

src/display/graphics.cpp

@@ -44,6 +44,7 @@
 #include <SDL_image.h>
 #include <SDL_timer.h>
 #include <SDL_video.h>
+#include <SDL_mutex.h>
 
 #ifdef MKXPZ_STEAM
 #include "steamshim_child.h"
@@ -435,6 +436,7 @@ struct GraphicsPrivate {
     Quad screenQuad;
     
     std::vector<unsigned long long> avgFPSData;
+    SDL_mutex *avgFPSLock;
     
     /* Global list of all live Disposables
      * (disposed on reset) */
@@ -448,6 +450,7 @@ struct GraphicsPrivate {
     frameCount(0), brightness(255), fpsLimiter(frameRate),
     useFrameSkip(rtData->config.frameSkip), frozen(false), last_update() {
         avgFPSData = std::vector<unsigned long long>();
+        avgFPSLock = SDL_CreateMutex();
         
         recalculateScreenSize(rtData);
         updateScreenResoRatio(rtData);
@@ -462,7 +465,11 @@ struct GraphicsPrivate {
         fpsLimiter.resetFrameAdjust();
     }
     
-    ~GraphicsPrivate() { TEXFBO::fini(frozenScene); }
+    ~GraphicsPrivate() {
+        TEXFBO::fini(frozenScene);
+        SDL_DestroyMutex(avgFPSLock);
+        
+    }
     
     void updateScreenResoRatio(RGSSThreadData *rtData) {
         Vec2 &ratio = rtData->sizeResoRatio;
@@ -555,12 +562,13 @@ struct GraphicsPrivate {
         
         swapGLBuffer();
         
-        
-        if (avgFPSData.size() > 30)
+        SDL_LockMutex(avgFPSLock);
+        if (avgFPSData.size() > 40)
             avgFPSData.erase(avgFPSData.begin());
         
         unsigned long long time = shState->runTime();
         avgFPSData.push_back(time - last_update);
+        SDL_UnlockMutex(avgFPSLock);
         
         last_update = time;
     }
@@ -581,10 +589,13 @@ struct GraphicsPrivate {
     
     double averageFPS() {
         double ret;
+        SDL_LockMutex(avgFPSLock);
         for (unsigned long long times : avgFPSData)
             ret += times;
         
-        return 1 / (ret / avgFPSData.size() / 1000 / 1000);
+        ret = 1 / (ret / avgFPSData.size() / 1000000);
+        SDL_UnlockMutex(avgFPSLock);
+        return ret;
     }
 };
 
@@ -615,10 +626,6 @@ unsigned long long Graphics::getDelta() {
 
 void Graphics::update() {
     p->checkShutDownReset();
-    auto test = p->averageFPS();
-    if (test > 30) {
-        int a = 1;
-    }
     p->checkSyncLock();
     
 #ifdef MKXPZ_STEAM

src/eventthread.cpp

@@ -32,6 +32,7 @@
 #include <al.h>
 #include <alc.h>
 #include <alext.h>
+#include <cmath>
 
 #include "sharedstate.h"
 #include "graphics.h"
@@ -137,11 +138,6 @@ void EventThread::process(RGSSThreadData &rtData)
 	fullscreen = rtData.config.fullscreen;
 	int toggleFSMod = rtData.config.anyAltToggleFS ? KMOD_ALT : KMOD_LALT;
 
-	fps.lastFrame = SDL_GetPerformanceCounter();
-	fps.displayCounter = 0;
-	fps.acc = 0;
-	fps.accDiv = 0;
-
 	if (rtData.config.printFPS)
 		fps.sendUpdates.set();
 
@@ -314,8 +310,8 @@ void EventThread::process(RGSSThreadData &rtData)
 			{
 				if (!displayingFPS)
 				{
-					fps.immInitFlag.set();
-					fps.sendUpdates.set();
+
+                    fps.sendUpdates.set();
 					displayingFPS = true;
 				}
 				else
@@ -751,36 +747,8 @@ void EventThread::notifyFrame()
 	if (!fps.sendUpdates)
 		return;
 
-	uint64_t current = SDL_GetPerformanceCounter();
-	uint64_t diff = current - fps.lastFrame;
-	fps.lastFrame = current;
-
-	if (fps.immInitFlag)
-	{
-		fps.immInitFlag.clear();
-		fps.immFiniFlag.set();
-
-		return;
-	}
-
-	static uint64_t freq = SDL_GetPerformanceFrequency();
-
-	double currFPS = (double) freq / diff;
-	fps.acc += currFPS;
-	++fps.accDiv;
-
-	fps.displayCounter += diff;
-	if (fps.displayCounter < freq && !fps.immFiniFlag)
-		return;
-
-	fps.displayCounter = 0;
-	fps.immFiniFlag.clear();
-
-	int32_t avgFPS = fps.acc / fps.accDiv;
-	fps.acc = fps.accDiv = 0;
-
 	SDL_Event event;
-	event.user.code = avgFPS;
+	event.user.code = round(shState->graphics().averageFrameRate());
 	event.user.type = usrIdStart + UPDATE_FPS;
 	SDL_PushEvent(&event);
 }

src/eventthread.h

@@ -131,13 +131,7 @@ private:
 
 	struct
 	{
-		uint64_t lastFrame;
-		uint64_t displayCounter;
 		AtomicFlag sendUpdates;
-		AtomicFlag immInitFlag;
-		AtomicFlag immFiniFlag;
-		double acc;
-		uint32_t accDiv;
 	} fps;
 };