Changed UpdateFpsValue() in vtk UI actor class to use a deque for a s…

…liding average of time between frames
f3d-app · Jan 6, 2025 · 42bc7e4 · 42bc7e4
1 parent fa483f2
commit 42bc7e4
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Showing 3 changed files with 24 additions and 22 deletions.
diff --git a/vtkext/private/module/vtkF3DRenderer.cxx b/vtkext/private/module/vtkF3DRenderer.cxx
@@ -1547,20 +1547,19 @@ void vtkF3DRenderer::Render()
 
   if (! uiOnly)
   {
-  // Get CPU frame per seconds
-  int fps = static_cast<int>(std::round(
-    1.0 / (std::chrono::duration_cast<std::chrono::microseconds>(cpuElapsed).count() * 1e-6)));
+	  // Get CPU frame time
+	  double elapsedTime = std::chrono::duration_cast<std::chrono::microseconds>(cpuElapsed).count() * 1e-6;
 
 #if !defined(__ANDROID__) && !defined(__EMSCRIPTEN__)
-  glEndQuery(GL_TIME_ELAPSED);
-  GLint elapsed;
-  glGetQueryObjectiv(this->Timer, GL_QUERY_RESULT, &elapsed);
+	  glEndQuery(GL_TIME_ELAPSED);
+	  GLint elapsed;
+	  glGetQueryObjectiv(this->Timer, GL_QUERY_RESULT, &elapsed);
 
-  // Get min between CPU frame per seconds and GPU frame per seconds
-  fps = std::min(fps, static_cast<int>(std::round(1.0 / (elapsed * 1e-9))));
+	  // Get min between CPU frame time and GPU frame time
+	  elapsedTime = std::min(elapsedTime, elapsed * 1e-9);
 #endif
 
-  this->UIActor->UpdateFpsValue(fps);
+	  this->UIActor->UpdateFpsValue(elapsedTime);
   }
 }
 

diff --git a/vtkext/private/module/vtkF3DUIActor.cxx b/vtkext/private/module/vtkF3DUIActor.cxx
@@ -4,6 +4,8 @@
 #include <vtkOpenGLRenderWindow.h>
 #include <vtkViewport.h>
 
+#include <numeric>
+
 vtkObjectFactoryNewMacro(vtkF3DUIActor);
 
 //----------------------------------------------------------------------------
@@ -67,18 +69,19 @@ void vtkF3DUIActor::SetFpsCounterVisibility(bool show)
 }
 
 //----------------------------------------------------------------------------
-void vtkF3DUIActor::UpdateFpsValue(int fps)
+void vtkF3DUIActor::UpdateFpsValue(const double elapsedMicroSeconds)
 {
-  this->AccumulatedFpsValue += fps;
-  this->FramesAccumulated++;
+	this->FrameTimes.push_back(elapsedMicroSeconds);
 
-  if (this->FramesAccumulated == vtkF3DUIActor::FramesToAverage)
-  {
-	  this->FpsValue = static_cast<int>(this->AccumulatedFpsValue / this->FramesAccumulated);
+	// add window size check here
+	if (this->FrameTimes.size() == 6)
+	{
+		this->FrameTimes.pop_front();
+	}
 
-	  this->AccumulatedFpsValue = 0;
-	  this->FramesAccumulated = 0;
-  }
+	double averageFrameTime = std::accumulate(this->FrameTimes.begin(), this->FrameTimes.end(), 0.0) / this->FrameTimes.size();
+
+	this->FpsValue = static_cast<int>(std::round(1.0 / averageFrameTime));
 }
 
 //----------------------------------------------------------------------------

diff --git a/vtkext/private/module/vtkF3DUIActor.h b/vtkext/private/module/vtkF3DUIActor.h
@@ -9,6 +9,7 @@
 #define vtkF3DUIActor_h
 
 #include <vtkProp.h>
+#include <deque>
 
 class vtkOpenGLRenderWindow;
 
@@ -84,7 +85,7 @@ class vtkF3DUIActor : public vtkProp
    * Updates the fps value
    * 0 by default
    */
-  void UpdateFpsValue(int fps);
+  void UpdateFpsValue(const double elapsedMicroSeconds);
 
   /**
    * Set the font file path
@@ -160,10 +161,9 @@ class vtkF3DUIActor : public vtkProp
 
   bool FpsCounterVisible = false;
 
-  static const int FramesToAverage = 5;
-  int FramesAccumulated = 0;
+  // deque instead of queue to allow for iteration
+  std::deque<double> FrameTimes;
 
-  int AccumulatedFpsValue = 0;
   int FpsValue = 0;
 
   std::string FontFile = "";