[Ves] Modifying actors properties before rendering them

[Pat Marion]

Hi Carlos,

Are you using the VES library alone, or are you also using the kiwi library
(and VTK)?  Kiwi provides convenience methods for using VTK to load jpg and
png images and convert them into vesImage.  See
vesKiwiViewerApp::setBackgroundTexture().

I may be misunderstanding, but I think, for the trihedron, what you are
looking for is the overlay api.  We use this to render text using textured
quads.  Overlay nodes will be excluded from the scene bounds computation,
and they will be rendered on top of other actors in the scene.  You can see
some example code of its usage in the kiwi class
vesKiwiText2DRepresentation.  I've only used it for 2d text positioning,
maybe it won't be useful for your use case.  In the future I hope we can
build an example app that does this type of orientation marker.

Pat

On Thu, Mar 21, 2013 at 6:20 PM, Carlos <ves at calculoandamios.com> wrote:

> Hi,
>
> Regarding the first question about fixing the trihedron in the screen I
> will
> try to suggestion but I ' afraid that setting the ReferenceFrame to
> Absolute
> it will change also the orientation behavior.  that is something that the
> trihedron must match to the scene, as it gives orientation information.
> The goal is to display geometric objects in the space and the trihedron
> gives the orientation but is fixed in the screen , ie, the translation is
> blocked. A similar feature can be found in CAD software.
> At this point I forgot to ask about if there is in VES a similar flag to
> SetUseBounds() in order to avoid use the bound of one specific actor to
> calculate the bounds of the scene.
> I will post the checkings with setReferenceFrame.
>
>
> Regarding the possibility to add a image (jpg for example) to the
> background
> I already checked vesBackground.h and I saw some functions that could work,
> specially setimage, that accepts a vesImage object. But in vesImage.h the
> best function I have found is setData(const void *data, unsigned int size).
> At this point I'm block as I do not know how to read a jpg file and pass it
> to this function. Does setdata accept an vtkImageData object or something
> similar?
>
> Regards,
>
> Carlos
>
>
>
> -----Mensaje original-----
> De: Aashish Chaudhary [mailto:aashish.chaudhary at kitware.com]
> Enviado el: miércoles, 20 de marzo de 2013 22:44
> Para: Carlos
> CC: ves at public.kitware.com
> Asunto: Re: [Ves] Modifying actors properties before rendering them
>
> Hi Carlos,
>
> On Wed, Mar 20, 2013 at 5:22 PM, Carlos <ves at calculoandamios.com> wrote:
> > Hi,
> >
> >
> >
> > In VTK I have derived the vtkAxesActor class in order to fix the
> > trihedron in a fixed place on the screen. For this I have override the
> > RenderOpaqueGeometry() method that is called for each actor when a
> > renderer->render() is invoked and I modify the position of the Axes to
> > display it in the desired position.
>
> Have a look at the vesTransformInteface.h. Based on your description, I am
> thinking that you can call setReferenceFrame on the actor and pass it
> vesTransformInterface::Absolute option.
>
> >
> >
> >
> > I’m aware of the limitations of this class in VES as it has been
> > discussed in a previous thread but I would like to know if there is a
> > similar way to modify the position of one actor before rendering it
> > with the camera parameters already established. My problem is that I
> > do not fully understand the workflow generated after a
> > renderer->render() call. I have checked the VES code and there are
> > some other classes involved as vesVisitor that I do not understand.
> >
> >
> >
> > In VTK I also display an image background using a second camera not
> > related with the interactor but as I understand it is not possible to
> > use a second camera in VES. I’m thinking in using the first approach
> > and modify the image position before rendering it. Does it make sense?
>
> You can grab the background object from the renderer then you can set an
> image on it. Look at the vesRenderer.h and vesBackground.h headers.
>
> Let me know if this helps.
>
> >
> >
> >
> > Regards,
> >
> >
> >
> > Carlos
> >
> >
> >
> >
> > _______________________________________________
> > Ves mailing list
> > Ves at public.kitware.com
> > http://public.kitware.com/cgi-bin/mailman/listinfo/ves
> >
>
>
>
> --
> | Aashish Chaudhary
> | R&D Engineer
> | Kitware Inc.
> | www.kitware.com
>
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