H Boon, This is a driver/hardware specific issue rather than an OSG one. If you want to understand this then it would be best to approach the NVidia or Intel support forums.
Robert. On 17 March 2014 02:22, Boon Wah <[email protected]> wrote: > Hi, > > It appears that within texture.cpp in core OSG library, glTexImage2D > is faster than glCompressedTexImage2D by about 80 - 100%. > > glTexImage2D is used when the texture data is uncompressed (e.g. > RGB24) and glCompressedTexImage2D is used when the texture data is > compressed (e.g. S3DXT1). > > I have time the execution on both Nvidia GPU and Intel HD4000 > graphics. The timing difference is similar when using compressed and > uncompressed. I have only profile this on Windows platform using the latest > NVIDIA and Intel drivers. For NVIDIA driver, I have specifically enable > full graphics performance using its control panel. In addition, I have > tried to compile my texture with NVTT and it gives the same performance > close to S3DXT1. > > I will like to understand on why compressed data takes longer to load > onto GPU whereas uncompressed data performance is better. > > Will appreciate if somebody can enlighten me on this. Thanks in > advance. > > > Kind Regards, > Boon Wah > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=58616#58616 > > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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