[PATCH] Fix frame rate counter

[historic_bruno]

The frame rate counter (Shift+F) jumps around too much, the implementation should be filtering the time between frames to produce a smooth average, but it's obviously not working as intended.

[sbte]

100 frames average FPS patch

[sbte]

I added a patch that keeps an average over 100 frames and shows that as the FPS. This is certainly a lot smoother. It also checks for huge spikes, to compensate for instance for going from the loading screen to the game.

What the previous method did was only changing the FPS if there was a spike over an average of 3 frames. This is why you experienced it as jumping around a lot.

I hope you like the patch.

[historic_bruno]

Thanks for the patch. I've tested and it's somewhat of an improvement. If I understand the code, it's taking the "smoothed" frequency from an IIR filter and doing a moving average over 100 frames. This average/stable frequency is only used for FPS display.

The only problem I see is that 100 frames doesn't always seem to be appropriate. For example, on the main menu, I'm getting over 800 fps right now, so 100 frames is only 1/8 of a second, which causes lots of fluctuation. Using a larger number of samples seems to work well, like 500-100 frames. It will respond more slowly to relatively small changes in frequency, but I don't think that is necessarily undesirable for a fps counter. If someone wants more accurate performance info they should use the profiler or some other tool anyway. Or maybe there's a way to adjust the sample size on the fly?

Any thoughts?

[fabio]

What about updateing the display every second, counting the frames in it?

[sbte]

Patch to take an average over the last 2 seconds

[sbte]

You indeed understood my patch correctly. I now modified the patch to take an average over the last two seconds instead of the last 100 frames. Is that better?

I don't think we can ever get a stable amount of FPS in the menu, unless we only change the FPS that are displayed at a certain interval (say one second). But I don't think that's needed either. For me at least, the stability of the FPS in the game seems quite reasonable.

[ben]

In 13204:

Improves frame rate counter to give smoother results, patch by sbte. Fixes #1016

[historic_bruno]

Looks good to me, thanks!