[x3d-public] event utility usage, and event tracing techniques

Michael Aratow maratow at noegenesis.com
Sun Oct 30 09:34:38 PDT 2016


If we take WebVR into consideration, these types of delays are significant.

Do you anticipate problems?  End to end system delay in VR systems must 
be 20 milliseconds or less to avoid simulator sickness.


On 10/30/16 7:59 AM, Andreas Plesch wrote:
> Hello,
>
> cobweb_dom v0.7 is now available. It has full support for 
> ProtoInstance nodes and basic event tracing capability.
>
> v0.7 requires the latest development cobweb.js, eg cobweb > 2.3 .
>
> Event tracing to the console can be enabled by providing a 'trace' 
> attribute to the X3DCanvas element (with any value).
>
> All output x3d events are logged. Here is an example:
>
> 1477837418917000: Background  x3d_isBound: true
> 1477837418918000: Background  x3d_bindTime: 1477837418.9007943
> 1477837418919000: Viewpoint  x3d_isBound: true
> 1477837418920000: Viewpoint  x3d_bindTime: 1477837418.9007943
> 1477837421509000: CylinderSensor aroundX x3d_isOver: true
> ...
>
> (using 
> https://andreasplesch.github.io/cobweb_dom//tests/interactiveTransformations.xhtml 
> )
>
> The frontal time stamp is the DOM event creation time stamp in 
> microseconds produced by the web browser and available to DOM event 
> listeners.
> It is interesting to see the difference between the time stamp and say 
> the bindTime of the Background node, 18.918s - 18.901s = 17 ms
> or for Viewpoint: 18.920 - 18.901 = 19 ms.
> So it takes a bit for cobweb to call the event callback which creates 
> the DOM event.
> When a DOM event listener captures the event, it may be a little later 
> again.
> With a fps of 30, a frame lasts 33ms.
> It will be interesting to compare what time stamps and values are 
> reported with the x3d-edit trace scripts.
>
> -Andreas
>
>
>
> On Sat, Oct 29, 2016 at 8:00 PM, Andreas Plesch 
> <andreasplesch at gmail.com <mailto:andreasplesch at gmail.com>> wrote:
>
>     On Oct 29, 2016 6:20 PM, "Don Brutzman" <brutzman at nps.edu
>     <mailto:brutzman at nps.edu>> wrote:
>     >
>     > On 10/29/2016 2:21 PM, Andreas Plesch wrote:
>     >>
>     >> [...]
>     >>
>     >> Since logging all fields for all nodes becomes quickly a bit
>     overwhelming, it would be a nice touch to be able select in the
>     GUI which fields are traced (by default all).
>     >
>     >
>     > excellent idea.  not easily accomplished with current setup, but
>     will keep it in mind as a future feature in X3D-Edit.
>     >
>     > for that matter, couldn't someone someday somewhere create such
>     a widget in HTML that listened to all ROUTEs, as selected?  8)
>
>     It should be possible find all elements referenced by fromNode
>     attributes in ROUTE elements and attach event listeners with
>     handlers which just log to the console. Let me give it a try.
>
>     Andreas
>
>
>
>
> -- 
> Andreas Plesch
> 39 Barbara Rd.
> Waltham, MA 02453
>
>
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