[vtkusers] How to capture images from ONLY the RenderWindow?

[Charles Boivin]

I believe vtkRenderWindow ends up instantiating something like a
vtkXMesaRenderWindow in the end (or whatever is more appropriate -- on
Windows, it ends up instantiating a vtkWin32OpenGLRenderWindow). 

I am relatively new to VTK, and have never used it under anything else
than Windows, so that is about as far as I know, unfortunately.
Hopefully people with more Linux/Unix experience will be able to help
here...

Good luck,

Charles

>>> "Jared Cohen" <Jared.Cohen at noaa.gov> 10/27/04 01:12pm >>>
Actually, I'm not using "Mesa"; I'm using a regular vtkRenderWindow. Do

I need to use the Mesa version before offscreen rendering will work?

Charles Boivin wrote:

>Hi Jared,
>
>Hmmm.... I am running in the evil world of Microsoft, so I would not
>know anything about the MESA business. 
>
>Documentation says:
>
>virtual void vtkWindow::SetOffScreenRendering  	(int)  
	
>[virtual]
>  	
>Create a window in memory instead of on the screen. This may not be
>supported for every type of window and on some windows you may need
to
>invoke this prior to the first render.
>
>Reimplemented in vtkWin32OpenGLRenderWindow, vtkXMesaRenderWindow,
and
>vtkXOpenGLRenderWindow. 
>
>I am assuming that you are running a vtkXMesaRenderWindow then... I
>must say that the last sentence (about invoking this before the first
>render) is a bit strange, as I am not too sure how this would work
out.
>
>
>Sorry I could not be of more help...
>
>Charles
>
>  
>
>>>>"Jared Cohen" <Jared.Cohen at noaa.gov> 10/27/04 12:14pm >>>
>>>>        
>>>>
>Hi Charles, thanx for the quick reply! :-)
>
>Yes, I tried offscreen rendering, but it didn't seem to make any 
>difference at all. Do I need to enable this "MESA" thing before 
>offscreen rendering will work?
>
>Charles Boivin wrote:
>
>  
>
>>Hey Jared,
>>
>>Have you tried using offscreen rendering? Something like this:
>>
>>this->renWin->SetOffScreenRendering(1);
>>
>>... take a snapshot of the render window here
>>
>>this->renWin->SetOffScreenRendering(0);
>>
>>I use this to output a series of snapshots (to later create an
>>animation) and it seems to work fine for me, although I do not have
>>multiple windows that overlap each other. 
>>
>>Hope this helps,
>>
>>Charles
>>
>> 
>>
>>    
>>
>>>>>"Jared Cohen" <Jared.Cohen at noaa.gov> 10/27/04 11:35am >>>
>>>>>       
>>>>>
>>>>>          
>>>>>
>> Hi all. I'm part of a team that's building a large, multi-window
>>    
>>
>GUI;
>  
>
>>one of the windows contains the VTK RenderWindow. We implemented a 
>>function to save the scene as a PNG, but there's a problem: if any
of
>>    
>>
>
>  
>
>>the other windows are in the way of the RenderWindow, they get 
>>incorporated into the resulting PNG snapshot! What I want to do is
>>    
>>
>take
>  
>
>>a snapshot of ONLY the contents of the RenderWindow, regardless of 
>>whether or not there are other windows in front of the RenderWindow.
>>    
>>
>Is
>  
>
>>there a way to do this?
>>
>> 
>>
>>    
>>
>
>  
>