Hi Brad, To benchmark, you can change the quality of the compression in TextureUtils.cpp. For the moment, the compression is set to nvtt::Quality_Production, using nvtt::Quality_Normal you should have much better result. As I remember from the nvtt documentation, nvtt::Quality_Normal is much faster and produces quite good result. When I have tested NVTT with VPB, I don't remember to have such difference between CPU and OpenGL, but maybe the texture compression does not take so much time compared to the rest of the VPB processing.
Cheers, Fabien -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Christiansen, Brad Sent: mardi 26 octobre 2010 13:00 To: OpenSceneGraph Users Subject: Re: [osg-users] Proposed changes to VPB re compression Hi, I have just finished some basic benchmarking of the three different compression methods I am playing with with some very surprising results (to me anyway : ) I created a small test app that used either the current GL context, NVTT with CUDA or vanilla CPU based NVTT to compress an image to a specified format. The image was compressed ten times and the total time taken is given in seconds. I ran the tests on two machines (one laptop and one desktop). Desktop Win7 3.2ghz CPU Geforce GTX275 -------------------------------------- CPU CUDA GL DXT1 17.0 1.47 0.66 DXT1a 14.22 0.47 DXT3 12.58 1.48 0.52 Laptop Win7 3.17ghz CPU ATI Mobility FireGL V5700 ------------------------------------------------- CPU GL DXT1 18.61 3.913 DXT1a 20.65 3.948 DXT3 18.13 0.977 The main surprise for me was how much faster using the current GL approach is compared to using NVTT. There is a big difference between the two video cards but both are much faster than the CPU. I was a bit disappointed at the CUDA results especially given this will only work on Nvidia cards and some formats (the DXT1a cuda score isn't given as this output format doesn't support cuda acceleration atm). Before these tests I was leaning towards defaulting to using NVTT for maximum compatibility but this doesn't look so good now. 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.or g ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
