[x3d-public] LOD first level_changed event

[Andreas Plesch]

https://x3d-lodlevel-test.glitch.me/LODwithDifferentShapes.x3d

tests if an initial level_changed event is generated. If it is,
'Choice 0' is displayed on front of the red cube, at first display. If
not, no text is displayed.

x marks the browser which show the text:

x3dom: x
Instant Player: x
H3DViewer: x
View3dScene: x

Octaga
BS Contact

FreeWrl
X-ITE


FreeWrl and X-ITE do not show text even after initialisation and
changing LOD levels. So they may not support level_changed.

Apparently there are differences in spec. interpretation.

-Andreas



On Fri, Apr 6, 2018 at 8:11 PM, Andreas Plesch <andreasplesch at gmail.com> wrote:
> LOD has an outputOnly level_changed field which indicates the level
> index of a child when it is activated.
>
> Should the level_changed event be generated the very first time the
> LOD activates any of its children ?
>
> It looks like it should and the spec. does not treat the
> initialization as a special case: When L(d) is activated for display,
> the LOD node generates a level_changed event with value i where the
> value of i identifies which value of L was activated for display.
>
> On the other hand, the first display may not be considered a change
> from a previous display. But it is a change from no display, and
> generally logic using the event should work for the initial case as
> well.
>
> So I think the answer is yes but thought it is worth raising the
> question before the field is added to x3dom.
>
> Perhaps it is time to put together a simple test using an existing LOD
> example by adding a route from level_changed to a switch node to see
> if it gets an initial value.
>
> Any feedback welcome,
>
> -Andreas
>
> --
> Andreas Plesch
> Waltham, MA 02453



-- 
Andreas Plesch
Waltham, MA 02453