[vtkusers] Rendering only selected renderers

[John Biddiscombe]

Janne

If it waa a seperate renderwindow, then the back buffer would still be valid and no update would be required, but because you've got essentially renderers in their own viewports, which are part of the same render context, it all gets wiped when a new render is requested and the 3D image has to be updated too. A kludge would be to copy the screen bits for the 3D region to the new back buffer after wiping, and stop the 3D renderer from re-rendering, by checking if an update is actually required. Quite messy. Better to use seperate renderwindows instead of viewports. Your solution is basically either split into seperat renderwindows, or manually intervene in the deep delvings of the renderers : is there a third way?

JB

RPD : A drag drop front end for vtk 
www.skippingmouse.co.uk


> -----Original Message-----
> From: Hämäläinen Janne [mailto:Janne.Hamalainen at hus.fi]
> Sent: 17 July 2003 12:58
> To: vtkusers at vtk.org
> Subject: [vtkusers] Rendering only selected renderers
> 
> 
> 	Hi all,
> 
> 	I've created a rendering window with four renderers on it.
> Basically, three of the renderers show 2D medical slices of 
> 3D volume and
> the fourth renderer shows 3D rendered volume. I control all 
> the interactions
> myself and have created distinct interactions for 2D and 3D. 
> 
> 	My problem is: when I interact with 2D images and call render(),
> also the 3D volume gets the command and slows down the 
> otherwise fast 2D
> manipulation. I would like to somehow separate these 
> processes so that if
> the 3D volume wasn't updated it would not interfere the 2D 
> manipulation and
> screen updating. I've understood that the renderwindow passes 
> the render
> command to all renderers, but I haven't figured out how to 
> manipulate this
> command line. Also, I don't understand why the 3D image is 
> rendered if it is
> not updated, i.e., shouldn't it just stay static and not interfere the
> screen updating. I would appreciate if someone could clear my mind.
> 
> 	Thanks,
> 
> 	-Janne
> 
> 
> 
> --
> Janne Hämäläinen
> Research Assistant
> Helsinki University Central Hospital 
> X-ray Department				
> 
> email   janne.hamalainen at hus.fi
> 
> 
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