Hi Robert,

Robert Osfield wrote:
Hi J.P,

I found that the GL driver support for properly accelerating the
reading from the GPU memory using PBO to be very sensitive for pixel
format, and if you fell off the past path it would indeed be slower.
It's a while since I implemented osgscreencapture so can't remember
all the details off hand, but have a look into forcing the use of the
RGBA frame buffer.

OK, I'll have a look at the format. I was actually triggered by one of our own apps that reads GL_LUMINANCE textures back (at half the speed with pbo than without) and then saw osgscreencapture exhibit the same trend. For some reason I thought I remembered osgscreencapture being faster with pbo (dual pbo is the default e.g.), but maybe my memory is wrong.

rgds
jp


Robert.

On Mon, Dec 7, 2009 at 9:39 AM, J.P. Delport <[email protected]> wrote:
Hi all,

running with latest svn OSG, the osgscreencapture example produces the best
speed for me (tested on a few machines) when run with the --no-pbo command
line parameter. All the pbo options (--single-pbo to --triple-pbo) are
slower. Is this expected? I've thought that the pbo versions would be
faster?

regards
jp

--
This message is subject to the CSIR's copyright terms and conditions, e-mail legal notice, and implemented Open Document Format (ODF) standard. The full disclaimer details can be found at http://www.csir.co.za/disclaimer.html.

This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. MailScanner thanks Transtec Computers for their support.

_______________________________________________
osg-users mailing list
[email protected]
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org

Reply via email to