FramerateLimitMode: add setting to improve accuracy at cost of higher CPU usage

Author: emoose

Outrun2006Tweaks.ini

@@ -4,16 +4,21 @@
 #  Set to 0 to disable this framelimiter, in case you want to use an external one instead.
 FramerateLimit = 60
 
+# FramerateLimitMode: Improve accuracy of the framerate limiter at a cost of higher CPU usage.
+#  0 = efficient mode
+#  1 = accurate mode
+FramerateLimitMode = 0
+
 # FramerateFastLoad: Unlimits framerate during load screens to help reduce load times.
 #  0 = disable
-#  1 = only unlimit framerate
-#  2 = unlimit framerate & disable vsync (fastest, but may cause screen flash)
+#  1 = unlimit framerate
+#  2 = unlimit framerate & disable vsync (fastest but may cause screen flash)
 FramerateFastLoad = 1
 
 # FramerateUnlockExperimental: Prevents game from speeding up when playing with FramerateLimit above 60FPS.
 #  Works by forcing game to only update at 60Hz, while rendering is allowed to run at a higher rate.
 #  Though since game still runs at 60Hz internally this isn't as good as a true framerate unlock, but might still be useful for some.
-#  (higher FPS also has issues with certain textures / UI elements being animated too quickly too, not too noticeable at 120/144, but can be disorientating at 3000+FPS)
+#  (certain textures/UI elements may animate faster at higher FPS, but gameplay should remain the same speed)
 #  Should be fine to leave this enabled in most cases, but if you have issues feel free to disable this here.
 FramerateUnlockExperimental = true
 

src/dllmain.cpp

@@ -84,6 +84,7 @@ namespace Settings
 		fclose(iniFile);
 
 		FramerateLimit = ini.Get("Performance", "FramerateLimit", std::move(FramerateLimit));
+		FramerateLimitMode = ini.Get("Performance", "FramerateLimitMode", std::move(FramerateLimitMode));
 		FramerateFastLoad = ini.Get("Performance", "FramerateFastLoad", std::move(FramerateFastLoad));
 		FramerateUnlockExperimental = ini.Get("Performance", "FramerateUnlockExperimental", std::move(FramerateUnlockExperimental));
 		VSync = ini.Get("Performance", "VSync", std::move(VSync));

src/hooks_framerate.cpp

@@ -83,26 +83,31 @@ class ReplaceGameUpdateLoop : public Hook
 				timeCurrent = double(counter.QuadPart) / FramelimiterFrequency;
 				timeElapsed = timeCurrent - FramelimiterPrevCounter;
 
-				if (FramelimiterTargetFrametime + FramelimiterDeviation <= timeElapsed)
+				if (Settings::FramerateLimitMode == 0) // "efficient" mode
 				{
-					FramelimiterDeviation = 0;
-					break;
+					if (FramelimiterTargetFrametime + FramelimiterDeviation <= timeElapsed)
+					{
+						FramelimiterDeviation = 0;
+						break;
+					}
+					else if ((FramelimiterTargetFrametime + FramelimiterDeviation) - timeElapsed > 2.0)
+						Sleep(1); // Sleep for ~1ms
+					else
+						Sleep(0); // Yield thread's time-slice (does not actually sleep)
 				}
-				else if ((FramelimiterTargetFrametime + FramelimiterDeviation) - timeElapsed > 2.0)
-					Sleep(1); // Sleep for ~1ms
-				else
-					Sleep(0); // Yield thread's time-slice (does not actually sleep)
 			} while (FramelimiterTargetFrametime + FramelimiterDeviation > timeElapsed);
 
 			QueryPerformanceCounter(&counter);
 			timeCurrent = double(counter.QuadPart) / FramelimiterFrequency;
 			timeElapsed = timeCurrent - FramelimiterPrevCounter;
 
+#if 0
 			// Compensate for the deviation in the next frame (based on dxvk util_fps_limiter)
 			double deviation = timeElapsed - FramelimiterTargetFrametime;
 			FramelimiterDeviation += deviation;
 			// Limit the cumulative deviation
 			FramelimiterDeviation = std::clamp(FramelimiterDeviation, -FramelimiterMaxDeviation, FramelimiterMaxDeviation);
+#endif
 
 			FramelimiterPrevCounter = timeCurrent;
 		}

src/plugin.hpp

@@ -35,6 +35,7 @@ namespace Game
 namespace Settings
 {
 	inline int FramerateLimit = 60;
+	inline bool FramerateLimitMode = 0;
 	inline int FramerateFastLoad = 1;
 	inline bool FramerateUnlockExperimental = true;
 	inline int VSync = 1;