Hi Brad, The behaviour does sounds rather surprising and odd, and don't have any immediate idea what might be wrong. To get to the bottom of it you'll likely have to do a series of tests to scope out the nature of the problem more.
One test I'd recommend is to try and different machine/OS/driver combination to see if this reveals anything of interest. Second, I'd do a test with pre compilation is off. You can switch it off by setting the env var OSG_DO_PRE_COMPILE to OFF. Personally I wouldn't expect pre compile to effect anything other than the merge time, it shouldn't effect the final frame rate. Another test would be to explore whether your hardware/drivers can actually run the texture format you've chosen. Robert. On 6 February 2012 02:14, Christiansen, Brad <[email protected]> wrote: > Hi, > > > > I am seeing some strange behaviour with the DatabasePager and compressed > textures (compressed using the nvtt image processor) and cant get my head > around what is happening. > > > > My setup is this: > > - A paged terrain very similar in nature to a VPB created terrain. > > - Images and height fields are stored in a database and read at runtime. As > the db uses aggressive mem caching, many reads of 'files' are actually read > straight from memory so images are loaded very quickly. > > > > To demonstrate the problem, I rapidly move the camera around the terrain to > generate lots of database requests. If the textures are not compressed (or > stored as jpegs etc, so they are not compressed once loaded) then the > precompilation works perfectly and I get no frame drops. If I change the > textures to use compressed dds images, I get terrible frame drops (down from > completely solid 60hz to bellow 20). > > > > I figured something was going wrong with the precompiler but after much > debugging this seems to be working as designed. If I set the max num of > objects to compile to 1 then the problem is reduced, but this is obviously > not a solution as it is just masking the problem. > > > > The only thing I can think of is that the precompiler isn't actually > uploading / compiling the textures when they are compressed, but it is when > they are not. As such, the precompilation stage races through lots of > textures and then during the draw phase the actual work is done, causing the > frame drops. However, I have no idea why this should be the case or how I > could address issue. > > > > Has anyone come across this before or have any suggestions as to what might > be going on? > > > > Cheers, > > Brad > > ------------------------------------------------------------------------- > DISCLAIMER: This e-mail transmission and any documents, files and previous > e-mail messages attached to it are private and confidential. They may > contain proprietary or copyright material or information that is subject to > legal professional privilege. They are for the use of the intended recipient > only. Any unauthorised viewing, use, disclosure, copying, alteration, > storage or distribution of, or reliance on, this message is strictly > prohibited. No part may be reproduced, adapted or transmitted without the > written permission of the owner. If you have received this transmission in > error, or are not an authorised recipient, please immediately notify the > sender by return email, delete this message and all copies from your e-mail > system, and destroy any printed copies. Receipt by anyone other than the > intended recipient should not be deemed a waiver of any privilege or > protection. Thales Australia does not warrant or represent that this e-mail > or any documents, files and previous e-mail messages attached are error or > virus free. > ------------------------------------------------------------------------- > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
