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How to get output from the eye-tracker faster than Update in Unity

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So in the specs it is said that the eye-tracker data output frequency is 120Hz, however, I can not get it higher than around 90Hz, which is the rate at which my scene is rendered. I tried with FixedUpdate with a small fixed timestamp, but it just repeats the fixation values on the extra cycles.

Could you tell me please if it is possible to obtain the output from the eye-tracker faster than the Updates happen? I apologize for possibly noob questions, but also, if I will make my scene render faster, will it help, considering that the vive itself refresh rate is 90 Hz?


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  • 2 weeks later...

There is callback mode supported in 120 FPS now after check "Enable Eye Data Callback" as the figure shown below; And, then register a callback function by SRanipal_Eye_v2.WrapperRegisterEyeDataCallback(). Could refer to its usage in sample included in SDK.




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  • 8 months later...

Hi @Corvus, I'm using callback method. According to @Daniel_Y I enabled v2 and then used sample UI code to show FPS from http://wiki.unity3d.com/index.php?title=FramesPerSecond&_ga=2.258332745.253243703.1593390743-1664584608.1593097261&fbclid=IwAR2zAe7hOiiEzb822jA5lIFOlpDGXqUhf-W2WYlbf00-B4uo-Y1-IhDqYtQ

I get 30 to 45 FPS. I checked my monitor frame rate is 60Hz. Please take a look at screenshot and let me know how can I get 120 FPS. 


Thanks in advance!



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Hi @Daniel_Y and @Corvus

I have several queries and findings :

1. In vive developer page I found that, refresh rate for headset and for eyetracking output frequency are different. For headset it is 90 hz and for eyetracking output frequency its 120 hz.


2.  I am getting different refresh rate for headset on different monitor. I tested on two monitors, one is Asus ROG(default monitor fps:144hz), another one is DELL(default monitor fps:60hz). From Asus ROG I have got 90 HZ frame rate for headset but from Dell monitor I am getting less than 60 hz. I wonder what relationship between monitor refresh rate and headset refresh rate is. Can you explain? I have calculated refresh rate using the following code:


3. Can you suggest or give example code how I can measure refresh rate for headset and eye tracking output frequency?

4. The last thing is: “Gaze data output frequency (binocular):120Hz” , to my understanding this means, we can collect 120 data points per second, right ? is there any dependency between Headset refresh rate and eye tracking output frequency?


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