Re: [Chromium-dev] Chromium and ParaView 2.0.1

[Brian P. <bri...@tu...>]

Joel Welling wrote:
>>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.

Hmmm, glReadPixels in the Pack SPU is pretty simple so I doubt the 
problem is there.


>>>  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.

I guess I'd talk to the ParaView folks at this point if I were you.

-Brian