Improve fps counter

[GabrielNakamoto]

Accumulate it over a few frames to give an average instead of showing the last frame performance only

• In vtkF3DUIActor I changed SetFpsValue() to UpdateFpsValue() which will automatically accumulate fps values before setting the display value to the average. The number of frames it waits to average is decided by the static member variable vtkF3DUIActor::FramesToAverage

Updating it only when the whole scene is rendered

• In the vtkF3DRenderer::Render() function I updated it to check if its information has vtkF3DRenderPass::RENDER_UI_ONLY() set to 1 If it does it calculates the fps value and calls the UI Actor's UpdateFpsValue()

Let me know what you think the number of frames to average should be (currently set to 5).

From building it and using some of the example models it seems that the render UI only is working however I may be wrong.

Seeing this is my first time contributing I'm starting a pull request to get some advice.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.67%. Comparing base (91310bd) to head (e42a67c).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1886      +/-   ##
==========================================
- Coverage   95.69%   95.67%   -0.03%     
==========================================
  Files         125      125              
  Lines        9926     9945      +19     
==========================================
+ Hits         9499     9515      +16     
- Misses        427      430       +3     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[mwestphal]

IMO it should be a slided average, wdyt ?

[GabrielNakamoto]

Yes that looks better. I can add that once I'm home from school.

[Meakk]

I think the average must be done in frame time, rather than fps.
So maybe you could pass the elapsed time in this function, average the elapsed time, and only inverse it at the end to convert to fps.
If you don't do that, the average will be biased with highest fps values.

Also, I don't like the idea of the fps value at 0 for the first 5 frames.

About the slided average, I'm afraid it will still produce large variation of fps and will still make the fps value unreadable. But maybe if we increase the window size to something larger than 5, this effect could be mitigated.

Here's a suggestion:

• Add the elapsed time in a container (std::queue but maybe another container is more adapted)
• Remove the oldest value if the number of elements is above the window size
• Average all the elements
• Inverse the value to get the fps value

Let's see if the value can be read and if changing the window size have an effect

[GabrielNakamoto]

Sounds good will try to implement this.

[GabrielNakamoto]

• Remove the oldest value if the number of elements is above the window size

How can the renderer get the window size (in it's information maybe?). And why should that affect the fps average?

[mwestphal]

This is looking good, wdyt @Meakk ?

[GabrielNakamoto]

I don't think the last commit works but I don't know why?