[vtkusers] Speed/vtkImageData

[Ted Vu]

Hi David thanks very much for your response,
I already have a good graphics card on my computer.. so this shouldnt be the 
problem..
Actually the values in the vtkFloatArray which I input into my ImageData is 
changed before every render, so to update the changes I was calling
   ImageData->Modified()
before every call to Render()..
(and also
   FloatArray->SetVoidArray( array, NumXpoints*NumYpoints, 1 )
right after my 'array' is updated with new values.. this is the FloatArray 
that is used by my ImageData)

So if I insert the following functions as well, then woudnt this slow things 
down..?
ImageData->UpdateInformation();
ImageData->SetUpdateExtent(ImageData->GetWholeExtent());
ImageData->Update();

I've used ImageViewer before and this seems pretty fast, but I have 3 actors 
so this is why I'm not using this class..

Okay thank-you again for your response!
Ted


>From: David Gobbi <dgobbi at imaging.robarts.ca>
>To: Ted Vu <lost_bits1110 at hotmail.com>
>CC: vtkusers at vtk.org
>Subject: Re: [vtkusers] Speed/vtkImageData
>Date: Thu, 1 Apr 2004 14:07:10 -0500 (EST)
>
>Hi Ted,
>
>Make sure the whole of the ImageData has been updated.  I suspect
>that the reason things are slow is that it is continuously re-reading
>the data from disk, either that or it is continuously re-executing
>upstream portions of the pipeline.
>
>To update the whole ImageData:
>ImageData->UpdateInformation();
>ImageData->SetUpdateExtent(ImageData->GetWholeExtent());
>ImageData->Update();
>
>If this is the first time that the ImageData has been updated,
>you can just do ImageData->Update() and skip the rest.
>
>Also, since ImageActor renders the image via texture maps, make sure
>that you have a good 3D graphics card in your computer.
>
>  - David
>
>
>On Thu, 1 Apr 2004, Ted Vu wrote:
>
> > Hi
> > Is there any way I can speed up rendering of 2D vtkImageData?
> >
> > My pipeline is
> >
> > ImageData -> ImageMapToColors -> ImageActor
> >
> > I have 3 of these ImageData's which appear on one Renderer
> >
> > Can I somehow use LODActor do you think?
> >
> > Thanks!
> >
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