make the fps counter more stable

src/Gui/Quarter/QuarterWidget.cpp

@@ -297,7 +297,7 @@ QuarterWidget::constructor(const QtGLFormat & format, const QtGLWidget * sharewi
 
   this->installEventFilter(PRIVATE(this)->eventfilter);
   this->installEventFilter(PRIVATE(this)->interactionmode);
-  
+
   initialized = false;
 }
 
@@ -844,8 +844,6 @@ void QuarterWidget::paintEvent(QPaintEvent* event)
         PRIVATE(this)->soeventmanager->setViewportRegion(vp);
     }
 
-    std::clock_t begin = std::clock();
-
     if(!initialized) {
 #if !defined(HAVE_QT5_OPENGL)
         glEnable(GL_DEPTH_TEST);
@@ -917,9 +915,6 @@ void QuarterWidget::paintEvent(QPaintEvent* event)
     // process the delay queue the next time we enter this function,
     // unless we get here after a call to redraw().
     PRIVATE(this)->processdelayqueue = true;
-
-    std::clock_t end = std::clock();
-    renderTime = double(double(end-begin)/CLOCKS_PER_SEC)*1000.0;
 }
 
 bool QuarterWidget::viewportEvent(QEvent* event)

src/Gui/Quarter/QuarterWidget.h

@@ -199,13 +199,11 @@ protected:
   virtual void actualRedraw(void);
   virtual bool updateDevicePixelRatio(void);
 
-  double renderTime;
-
 private:
   void constructor(const QtGLFormat& format, const QtGLWidget* sharewidget);
   friend class QuarterWidgetP;
   class QuarterWidgetP * pimpl;
-  bool initialized;  
+  bool initialized;
 };
 
 }}} // namespace

src/Gui/Quarter/SoQTQuarterAdaptor.cpp

@@ -168,6 +168,8 @@ void SIM::Coin3D::Quarter::SoQTQuarterAdaptor::init()
 
     m_seeksensor = new SoTimerSensor(SoQTQuarterAdaptor::seeksensorCB, (void*)this);
     getSoEventManager()->setNavigationState(SoEventManager::NO_NAVIGATION);
+
+    resetFrameCounter();
 }
 
 
@@ -701,3 +703,38 @@ bool SIM::Coin3D::Quarter::SoQTQuarterAdaptor::processSoEvent(const SoEvent* eve
 
     return SIM::Coin3D::Quarter::QuarterWidget::processSoEvent(event);
 }
+
+/*!
+  Overridden from QuarterWidget to render the scenegraph
+*/
+void SIM::Coin3D::Quarter::SoQTQuarterAdaptor::paintEvent(QPaintEvent* event)
+{
+    QuarterWidget::paintEvent(event);
+
+    this->framesPerSecond = addFrametime(SbTime::getTimeOfDay().getValue());
+}
+
+void SIM::Coin3D::Quarter::SoQTQuarterAdaptor::resetFrameCounter(void)
+{
+    this->framecount = 0;
+    this->frames.assign(100, 0.0f);
+    this->totaldraw = 0.0f;
+    this->starttime = SbTime::getTimeOfDay().getValue();
+    this->framesPerSecond = SbVec2f(0, 0);
+}
+
+SbVec2f SIM::Coin3D::Quarter::SoQTQuarterAdaptor::addFrametime(double timeofday)
+{
+    int framearray_size = 100;
+    this->framecount++;
+
+    int arrayptr = (this->framecount - 1) % framearray_size;
+
+    double renderTime = timeofday - this->starttime;
+    this->totaldraw += (float(renderTime) - this->frames[arrayptr]);
+    float drawfps = this->totaldraw / std::min<int>(this->framecount, framearray_size);
+
+    this->frames[arrayptr] = static_cast<float>(renderTime);
+    this->starttime = timeofday;
+    return SbVec2f(1000 * drawfps, 1.0f / drawfps);
+}

src/Gui/Quarter/SoQTQuarterAdaptor.h

@@ -30,6 +30,7 @@
 #include <Inventor/sensors/SoTimerSensor.h>
 #include <Inventor/actions/SoGetMatrixAction.h>
 #include <Inventor/actions/SoSearchAction.h>
+#include <vector>
 
 class SbViewportRegion;
 class SoCamera;
@@ -96,7 +97,8 @@ public:
     }
     
     virtual bool processSoEvent(const SoEvent* event);
-          
+    virtual void paintEvent(QPaintEvent*);
+
     //this functions still need to be ported
     virtual void afterRealizeHook(void) {} //enables spacenav and joystick in soqt, dunno if this is needed
 
@@ -107,12 +109,20 @@ private:
     void getCameraCoordinateSystem(SoCamera * camera, SoNode * root, SbMatrix & matrix, SbMatrix & inverse);
     static void seeksensorCB(void * data, SoSensor * s);
     void moveCameraScreen(const SbVec2f & screenpos);
+    void resetFrameCounter(void);
+    SbVec2f addFrametime(double ft);
 
     bool m_viewingflag;
     int  m_interactionnesting;
     SoCallbackList m_interactionStartCallback;
     SoCallbackList m_interactionEndCallback;
 
+    // Keep track of the frames-per-second counter.
+    std::vector<float> frames;
+    float totaldraw;
+    double starttime;
+    int framecount;
+
     // Seek functionality
     SoTimerSensor* m_seeksensor;
     float m_seekperiod;
@@ -130,6 +140,7 @@ private:
 protected:
     void draw2DString(const char * str, SbVec2s glsize, SbVec2f position);
     void printString(const char * s);
+    SbVec2f framesPerSecond;
 };
 
 } //Quarter

src/Gui/View3DInventorViewer.cpp

@@ -1642,7 +1642,7 @@ void View3DInventorViewer::renderScene(void)
         std::stringstream stream;
         stream.precision(1);
         stream.setf(std::ios::fixed | std::ios::showpoint);
-        stream << renderTime << " ms / " << 1000./renderTime << " fps";
+        stream << framesPerSecond[0] << " ms / " << framesPerSecond[1] << " fps";
         draw2DString(stream.str().c_str(), SbVec2s(10,10), SbVec2f(0.1f,0.1f));
     }