Merge branch 'fix_frame_rate_limit' into 'master'

Fix frame rate limit (#5686)

See merge request OpenMW/openmw!603

apps/openmw/engine.cpp

@@ -38,6 +38,8 @@
 
 #include <components/detournavigator/navigator.hpp>
 
+#include <components/misc/frameratelimiter.hpp>
+
 #include "mwinput/inputmanagerimp.hpp"
 
 #include "mwgui/windowmanagerimp.hpp"
@@ -918,13 +920,15 @@ void OMW::Engine::go()
     }
 
     // Start the main rendering loop
-    osg::Timer frameTimer;
     double simulationTime = 0.0;
+    Misc::FrameRateLimiter frameRateLimiter = Misc::makeFrameRateLimiter(mEnvironment.getFrameRateLimit());
+    const std::chrono::steady_clock::duration maxSimulationInterval(std::chrono::milliseconds(200));
     while (!mViewer->done() && !mEnvironment.getStateManager()->hasQuitRequest())
     {
-        double dt = frameTimer.time_s();
-        frameTimer.setStartTick();
-        dt = std::min(dt, 0.2);
+        const double dt = std::chrono::duration_cast<std::chrono::duration<double>>(std::min(
+            frameRateLimiter.getLastFrameDuration(),
+            maxSimulationInterval
+        )).count();
 
         mViewer->advance(simulationTime);
 
@@ -960,7 +964,7 @@ void OMW::Engine::go()
             }
         }
 
-        mEnvironment.limitFrameRate(frameTimer.time_s());
+        frameRateLimiter.limit();
     }
 
     // Save user settings

apps/openmw/mwbase/environment.cpp

@@ -1,8 +1,6 @@
 #include "environment.hpp"
 
 #include <cassert>
-#include <chrono>
-#include <thread>
 
 #include <components/resource/resourcesystem.hpp>
 
@@ -98,19 +96,6 @@ float MWBase::Environment::getFrameRateLimit() const
     return mFrameRateLimit;
 }
 
-void MWBase::Environment::limitFrameRate(double dt) const
-{
-    if (mFrameRateLimit > 0.f)
-    {
-        double thisFrameTime = dt;
-        double minFrameTime = 1.0 / static_cast<double>(mFrameRateLimit);
-        if (thisFrameTime < minFrameTime)
-        {
-            std::this_thread::sleep_for(std::chrono::duration<double>(minFrameTime - thisFrameTime));
-        }
-    }
-}
-
 MWBase::World *MWBase::Environment::getWorld() const
 {
     assert (mWorld);

apps/openmw/mwbase/environment.hpp

@@ -83,7 +83,6 @@ namespace MWBase
 
             void setFrameRateLimit(float frameRateLimit);
             float getFrameRateLimit() const;
-            void limitFrameRate(double dt) const;
 
             World *getWorld() const;
 

apps/openmw/mwgui/windowmanagerimp.cpp

@@ -50,6 +50,7 @@
 #include <components/widgets/tags.hpp>
 
 #include <components/misc/resourcehelpers.hpp>
+#include <components/misc/frameratelimiter.hpp>
 
 #include "../mwbase/inputmanager.hpp"
 #include "../mwbase/statemanager.hpp"
@@ -710,12 +711,11 @@ namespace MWGui
 
         if (block)
         {
-            osg::Timer frameTimer;
+            Misc::FrameRateLimiter frameRateLimiter = Misc::makeFrameRateLimiter(MWBase::Environment::get().getFrameRateLimit());
             while (mMessageBoxManager->readPressedButton(false) == -1
                    && !MWBase::Environment::get().getStateManager()->hasQuitRequest())
             {
-                double dt = frameTimer.time_s();
-                frameTimer.setStartTick();
+                const double dt = std::chrono::duration_cast<std::chrono::duration<double>>(frameRateLimiter.getLastFrameDuration()).count();
 
                 mKeyboardNavigation->onFrame();
                 mMessageBoxManager->onFrame(dt);
@@ -734,7 +734,7 @@ namespace MWGui
                 // refer to the advance() and frame() order in Engine::go()
                 mViewer->advance(mViewer->getFrameStamp()->getSimulationTime());
 
-                MWBase::Environment::get().limitFrameRate(frameTimer.time_s());
+                frameRateLimiter.limit();
             }
         }
     }
@@ -1750,11 +1750,10 @@ namespace MWGui
                 ~MWSound::Type::Movie & MWSound::Type::Mask
             );
 
-        osg::Timer frameTimer;
+        Misc::FrameRateLimiter frameRateLimiter = Misc::makeFrameRateLimiter(MWBase::Environment::get().getFrameRateLimit());
         while (mVideoWidget->update() && !MWBase::Environment::get().getStateManager()->hasQuitRequest())
         {
-            double dt = frameTimer.time_s();
-            frameTimer.setStartTick();
+            const double dt = std::chrono::duration_cast<std::chrono::duration<double>>(frameRateLimiter.getLastFrameDuration()).count();
 
             MWBase::Environment::get().getInputManager()->update(dt, true, false);
 
@@ -1777,7 +1776,7 @@ namespace MWGui
             // refer to the advance() and frame() order in Engine::go()
             mViewer->advance(mViewer->getFrameStamp()->getSimulationTime());
 
-            MWBase::Environment::get().limitFrameRate(frameTimer.time_s());
+            frameRateLimiter.limit();
         }
         mVideoWidget->stop();
 

components/misc/frameratelimiter.hpp

@@ -0,0 +1,56 @@
+#ifndef OPENMW_COMPONENTS_MISC_FRAMERATELIMITER_H
+#define OPENMW_COMPONENTS_MISC_FRAMERATELIMITER_H
+
+#include <chrono>
+#include <thread>
+
+namespace Misc
+{
+    class FrameRateLimiter
+    {
+        public:
+            template <class Rep, class Ratio>
+            explicit FrameRateLimiter(std::chrono::duration<Rep, Ratio> maxFrameDuration,
+                                      std::chrono::steady_clock::time_point now = std::chrono::steady_clock::now())
+                : mMaxFrameDuration(std::chrono::duration_cast<std::chrono::steady_clock::duration>(maxFrameDuration))
+                , mLastMeasurement(now)
+            {}
+
+            std::chrono::steady_clock::duration getLastFrameDuration() const
+            {
+                return mLastFrameDuration;
+            }
+
+            void limit(std::chrono::steady_clock::time_point now = std::chrono::steady_clock::now())
+            {
+                const auto passed = now - mLastMeasurement;
+                const auto left = mMaxFrameDuration - passed;
+                if (left > left.zero())
+                {
+                    std::this_thread::sleep_for(left);
+                    mLastMeasurement = now + left;
+                    mLastFrameDuration = mMaxFrameDuration;
+                }
+                else
+                {
+                    mLastMeasurement = now;
+                    mLastFrameDuration = passed;
+                }
+            }
+
+        private:
+            std::chrono::steady_clock::duration mMaxFrameDuration;
+            std::chrono::steady_clock::time_point mLastMeasurement;
+            std::chrono::steady_clock::duration mLastFrameDuration;
+    };
+
+    inline Misc::FrameRateLimiter makeFrameRateLimiter(float frameRateLimit)
+    {
+        if (frameRateLimit > 0.0f)
+            return Misc::FrameRateLimiter(std::chrono::duration<float>(1.0f / frameRateLimit));
+        else
+            return Misc::FrameRateLimiter(std::chrono::steady_clock::duration::zero());
+    }
+}
+
+#endif