[x3d-public] PlaneSensor behavior, was: [x3dom-users] port this example to X3DOM?

Andreas Plesch andreasplesch at gmail.com
Thu Jun 1 18:56:42 PDT 2017


Thanks, Michalis, for testing.
This prompted me to go back and check again the original scene (without the
offset) in cobweb available here:

https://gist.githubusercontent.com/andreasplesch/83771ec5959935d309db417387397952/raw/e98fc7bb39ff04b982add3b08e730da009c4119f/x3dconnector.x3d

And it turns out that cobweb actually also shows the initial jump, unlike
what I thought I had observed before.

So all browser behave the same, and the only question is if the original
scene just had missed this small issue.

Cheers, Andreas





On Thu, Jun 1, 2017 at 5:43 PM, Michalis Kamburelis <
michalis.kambi at gmail.com> wrote:

> 2017-06-01 21:40 GMT+02:00 Andreas Plesch <andreasplesch at gmail.com>:
> > Cobweb and perhaps other x3d browser do not require this offset value for
> > expected behaviour. This now raises the question which interpretation of
> > PlaneSensor is correct, eg. should the offset here be necessary ?
> >
> > http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/
> components/pointingsensor.html#PlaneSensor
> >
> > says:
> >
> > '..a translation_changed event is output which corresponds to the sum of
> the
> > relative translation from the original intersection point to the
> > intersection point of the new bearing in the plane plus the offset
> value.'
> >
> > As a relative translation I would interprete this language to mean that
> > translation_changed starts out with '0 0 0' and then accumulates from
> there.
> > In the example, translation_changed is routed to an transform with an
> > initial translation value of '1 -1 .01' which means that a '0 0 0'
> > translation would lead to the previously observed initial jump. Adding an
> > offset therefore seems necessary. So x3dom behaviour seems correct ?
> > Generally cobweb is more strict in following the spec, so I am little
> > surprised.
> >
>
> At least view3dscene also requires this offset, as I understood the
> specification in the same way as you. Without the offset, the green
> ball indeed will "jump" at the first drag to (0,0,0). With the offset,
> it's OK.
>
> I tested on x3d extracted from your
> https://glitch.com/edit/#!/jade-aluminum?path=views/index.html:34:0 .
>
> Regards,
> Michalis
>



-- 
Andreas Plesch
39 Barbara Rd.
Waltham, MA 02453
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