Re: Chromium and ParaView 2.0.1

> Joel Welling wrote:
> > Hi folks;
> >   Is anyone else running ParaView 2.0.1 through Chromium?  I am trying to get 
> > this together on our vis cluster, and there are problems with the ReadPixels 
> > of the sub-images from the various render servers for compositing (by Ice-T in 
> > ParaView) to make the whole image.  The sub-images look like they are being 
> > read back at the wrong resolution, such that adjacent pixels in the rendered 
> > image are not adjacent in the read-back image.
> 
> Are you running a basic tilesort configuration or is there something 
> else going on?

It's a simpler configuration than that- just a single pack SPU sending to a 
render SPU (or a print SPU followed by a render SPU).  Brian, I'll forward the 
config file to you under separate mail.  We use it basically to give the 
calling application access to a graphics card.

> 
> 
> >   I've looked at the images rendered on the individual crservers, and they 
> > look just great.  This system did work with earlier versions of ParaView 
> > (specifically 1.6.3), so I've compared the OpenGL calls made by the two 
> > versions.  The older version reads back images starting at pixel (0,0) and 
> > including the entire rendered area, while the new version seems to try to save 
> > bytes by only reading back the parts of the image where it thinks stuff has 
> > been drawn.  This means that ReadPixels is not done with a corner at (0,0).  
> > I'm guessing that perhaps there is a problem with ReadPixels of sections of 
> > the rendered image which do not include that corner.
> 
> The tilesort SPU tracks object bounding boxes but that's not used for 
> glReadPixels.  So I'm not sure why the coordinates are funny.
> 

Note that the coordinate change is apparently due to a change in ParaView, not 
to any intervention on Chromium's part.  I think it is this change (between 
ParaView 1.something and ParaView 2.0.1) that is messing up our application.

-Joel
 
> >   Note that my Chromium is not completely up-to-date from the top of the tree. 
> >  If any corrections have been made to the ReadPixels mechanism since Feb. 21 
> > they might solve my problem.
> 
> I don't think there's been any recent changes in ReadPixels in the 
> tilesort SPU.
> 
> -Brian




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