I use vtkRenderLargeImage (which renders large images by succesively rendering small portions of it) that connects to a vtkRenderer and produce a vtkImageData as an output, that can then be saved to a file using something like vtkPNGWriter.<br>
<br>I have 2 problems with that method though. <br><br>1 - With volume rendering, I get 1 pixel wide lines at the separation of the blocks (I suspect it is a bug in vtkRayCastImageDisplayHelper)<br>2 - When rendering animation, I need to create a new vtkRenderLargeImage everytime I change frame otherwise, it vtkRenderLargeImage always outputs the same frame even though the scene is changing.<br>
3 - There doesn't seem to be a way to avoid displaying a render window on the screen (at least it is the case on OSX with VTK built on COCOA). I have tried to set OffScreenRenderingOn on the window right after it is constructed (before any render occurs) and it is still showing the window.<br>
<br>s.<br><br><div class="gmail_quote">On Wed, Apr 15, 2009 at 3:51 PM, Kevin H. Hobbs <span dir="ltr"><<a href="mailto:hobbsk@ohiou.edu">hobbsk@ohiou.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
On Wed, 2009-03-25 at 21:57 -0400, Shari Rolnick wrote:<br>
> I’ve been using VTK with mangled Mesa to create offscreen<br>
> visualizations for some time, but from glancing through the more<br>
> recent documentation and mailing list archives, it looks like that is<br>
> no longer the preferred method, but I couldn’t figure out how to make<br>
> offscreen rendering work otherwise. In addition, it looks like (for<br>
> example) the vtkAxesActor does not work with mangled Mesa. (The<br>
> actors don’t show up in images that are generated offscreen.) Could<br>
> someone either direct me to an example or instructions for the “right”<br>
> way to do offscreen rendering now, or tell me how I might get the<br>
> vtkAxesActor working with mangled Mesa?<br>
><br>
><br>
><br>
> Thanks,<br>
> Shari<br>
<br>
The right way is to just build mesa and mesa's offscreen library osmesa.<br>
<br>
Then tell cmake to link VTK with mesa and osmesa.<br>
<br>
My CMakeCache.txt has these settings:<br>
<br>
VTK_OPENGL_HAS_OSMESA:BOOL=ON<br>
OPENGL_INCLUDE_DIR:PATH=/home/kevin/mesa/include<br>
OPENGL_gl_LIBRARY:FILEPATH=/home/kevin/mesa/lib64/libGL.so<br>
OPENGL_glu_LIBRARY:FILEPATH=/home/kevin/mesa/lib64/libGLU.so<br>
OSMESA_INCLUDE_DIR:PATH=/home/kevin/mesa/include<br>
OSMESA_LIBRARY:FILEPATH=/home/kevin/mesa/lib64/libOSMesa.so<br>
<br>
You can set them in ccmake to point to your own mesa build or set only<br>
VTK_OPENGL_HAS_OSMESA and set the environment variables<br>
CMAKE_LIBRARY_PATH and CMAKE_INCLUDE_PATH such that cmake finds files<br>
from mesa before system files and graphics libraries from ati or nvidia.<br>
<br>
Your operating system may provide mesa and osmesa.<br>
<br>
You may have to build two copies of VTK, one to use libraries from ati<br>
or nvidia and one to do offscreen rendering.<br>
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<br></blockquote></div><br>