[vtkusers] vtkInteractorStyleTrackballCamera renders unnecessarily

[Christoph Kolb]

Thank you for your reply!
We are actually not using the level of detail rendering and I see now 
the advantage of the two rendering steps. But still, in the case of a 
mousewheel event both steps are performed directly consecutively. This 
is what makes zooming particularly slow for us, because using the 
mousewheel triggers several events with two renderings each.

Is this also fixed if we would use the level of detail rendering ? Or 
would it be best in our case to override the TrackballInteractor?

Regards
Christoph

On 04/23/2014 05:11 PM, David Cole wrote:
>> ... an additional render call
>> is issued within StopState() at the
>> end of an Interaction.
> The second-to-last rendering is done while the interactor is still in
> an interactive state, and will therefore possibly be at a lower
> resolution/level-of-detail for volume rendering, or for level of detail
> actors. (Fast, interactive speed renderings, but possibly of lower
> quality...)
>
> The last rendering, issued during the StopState call, is made after the
> interactor is taken out of its interactive state, and will therefore be
> a full rendering, at highest level of detail. (Best quality rendering
> possible, but might be much slower...)
>
> If you are not taking advantage of any fast interactive renders with
> any actors in your scene, then you will not appreciate the difference.
> But for those of us who use the level of detail functionality, with
> lower quality fast renderings when interacting, and higher quality
> slower renderings when not interacting, *both* Render calls are
> definitely required.
>
>
> HTH,
> David C.
>
>