Fwd: Re: [vtkusers] on & offscreen render windows

[Michael Bonner]

>Date: Thu, 30 Sep 2004 09:43:14 -0700
>To: tom fogal <tfogal at apollo.sr.unh.edu>
>From: Michael Bonner <bonner10 at llnl.gov>
>Subject: Re: [vtkusers] on & offscreen render windows
>
>
>In my non-simplistic application the offscreen window contains data that I 
>am trying to composite over n processors. The root process contains data 
>to be composited (which the offscreen window is for) and an additional 
>render window, renderer, etc.. in which I hope to display the composite 
>image. During interaction I would only like to display the composite at 
>the users request (key press event, like 'r') or when movement stops 
>(mouse release event). While the mouse is moving I would only like a 
>bounding box or axis, to be rendered.
>
>I implemented a couple of ways to achieve this.. and nothing worked. I 
>distilled the problem down to the offscreen render on the root 
>process--this is the source of my simple example problem.
>
>So the answer to "I assume the offscreen window is getting saved to a 
>file?" is that it is being saved to a buffer... which is composited... and 
>then either shoved in to a 2d actor (which is in the on screen renderer, 
>and whose visibility is turned on/off) or into the on screen window w/ 
>SetRGBACharPixelData.
>
>I am not familiar w/ vtkWindowToImageFilter (so im going to check it out), 
>but my initial reaction is that I have separate data in each window.. one 
>of which needs to be composited offscreen among multiple processors.  My 
>only current solution is to only do on screen rendering on the root 
>process, and let the other processes do the offscreen composite.
>
>Thanks for your help
>-mike
>
>
>At 09:00 PM 9/29/2004 -0400, you wrote:
>>  <5.0.0.25.2.20040929161141.0286f220 at mail.llnl.gov>Michael Bonner writes:
>> >Hello vtk users,
>> >
>> >I am trying to use two vtkRenderWindows w/ two vtkRenderes in a single
>> >application. One of the render windows is offscreen, the other is not.  I
>> >would like to use the on screen render window for interaction, but, when a
>> >mouse key release event happens I would like the offscreen window to
>> >render.  I have included a small application that produces my problem. 
>> When
>>
>>I assume the offscreen window is getting saved to a file?
>>
>>Why not just use one vtkRenderer and use vtkWindowToImageFilter when
>>the mouse key release happens? Its likely that the simplicity of that
>>implementation would fix the weird bug you're seeing...
>>
>>Sorry if I'm misunderstanding...
>>
>>-tom
>>
>><snip>